/* jk intepreter, by @txlyre,www:txlyre.website, in the public domain */
#include<ctype.h>
#include<limits.h>
#include<math.h>
#include<setjmp.h>
#include<stdbool.h>
#include<stdint.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<time.h>
#include<unistd.h>
#include<sys/wait.h>
#include<errno.h>
#include<gc.h>
#include<ffi.h>
#include<dlfcn.h>
#define VER "0.1alep"
#define R return
#define BR break
#define CN continue
#define WH while
#define SW switch
#define CS case
#define T true
#define F false
#define N NULL
#define LOOP for(;;)
#define elif else if
#define FR(p) GC_FREE(p)
#define xt ((x)->tag)
#define yt ((y)->tag)
#define xa ((x)->val.array)
#define ya ((y)->val.array)
#define xad ((x)->val.array->data)
#define yad ((y)->val.array->data)
#define xal ((x)->val.array->length)
#define yal ((y)->val.array->length)
#define xn ((x)->val.number)
#define yn ((y)->val.number)
#define vn ((v)->val.number)
#define xV ((x)->val.verb)
#define yV ((y)->val.verb)
#define xY ((x)->val.symbol)
#define yY ((y)->val.symbol)
#define Vnc(c) (CHARS[(unsigned char)(c)])
typedef uint32_t U32;
typedef uint64_t U64;
typedef double D;
typedef unsigned char UC;
typedef char C;
typedef char *S;
typedef ssize_t SZ;
typedef size_t Z;
typedef bool B;
typedef unsigned int UI;
typedef int I;
typedef void *P;
typedef void V;
typedef const char *cS;
typedef const void *cP;
#define SO(t) (sizeof(t))
#define AE(x)(SO(x)/SO((x)[0]))
#define ROTL32(x, r) ((x << r) | (x >> (32 - r)))
#define FMIX32(h)                                                              \
  h ^= h >> 16;                                                                \
  h *= 0x85ebca6b;                                                             \
  h ^= h >> 13;                                                                \
  h *= 0xc2b2ae35;                                                             \
  h ^= h >> 16;
#define TABLE_MIN_SIZE 32
#define CV(s) (Srun(st,s)->val.verb)
jmp_buf Icp;
B Iin;
P ma(Z size){P p;
  if(!(p=GC_MALLOC(size)))abort();R p;}
P maa(Z size){P p;
  if(!(p=GC_malloc_atomic(size)))abort();
  memset(p,0,size);R p;}
P mau(Z size){P p;
  if(!(p=GC_malloc_uncollectable(size)))abort();
  memset(p,0,size);R p;}
P mrea(P p,Z size){if(!(p=GC_REALLOC(p,size)))abort();R p;}
S sdup(S s){S p=GC_strdup(s);
  if(!p)abort();R p;}
typedef struct{P*data;
  Z length;}Ar;
Ar*An(void){Ar*arr=ma(SO(Ar));
  arr->data=N;
  arr->length=0;R arr;}
Ar*Ank(Z k){Ar*arr=ma(SO(Ar));
  arr->data=ma(k*SO(P ));
  arr->length=k;R arr;}
Ar*Ac(Ar*l){Ar*arr=Ank(l->length);
  for(Z i=0;i<l->length;i++)arr->data[i]=l->data[i];R arr;}
V Ap(Ar*l,P v){Z i=l->length++;
  l->data=mrea(l->data,l->length*SO(P ));
  l->data[i]=v;}
P AP(Ar*l){if(!l->data)R N;
  Z i=--l->length;
  P v=l->data[i];
  l->data[i]=N;
  if(!l->length){FR(l->data);
    l->data=N;}else l->data=mrea(l->data,l->length*SO(P ));R v;}
P Ai(Ar*l,SZ index){if(!l->data)R N;
  if(index<0)index+=((SZ)l->length);
  if(index<0||index>=l->length)R N;R l->data[index];}
V As(Ar*l,SZ index,P v){if(!l->data)R;
  if(index<0)index+=((SZ)l->length);
  if(index<0||index>=l->length)R;
  l->data[index]=v;}
typedef struct{S str;
  Z used;
  Z allocated;}Bt;
Bt*Bnew(void){Bt*buf=ma(SO(Bt));
  buf->str=N;
  buf->used=buf->allocated=0;R buf;}
V Bappend(Bt*buf,C c){buf->used++;
  if(buf->used>buf->allocated){buf->allocated++;
    buf->str=mrea(buf->str,SO(char)*buf->allocated);}
  buf->str[buf->used-1]=c;}
S Bread(Bt*buf){if(buf->used==0||buf->str[buf->used-1])Bappend(buf,0);
  S str=buf->str;
  FR(buf);R str;}
V BappendS(Bt*buf,S s){WH(*s)Bappend(buf,*s++);}
typedef struct{enum Tkt{T_PUNCT,T_LPAR,T_RPAR,T_NAME,T_NUM,T_BNUM,T_QUOTE}tag;
  S text;}Tkt;
typedef struct{S source;
  Z len;
  Z pos;
  Ar*tokens;}Lt;
Lt*Lnew(void){Lt*lexer=ma(SO(Lt));R lexer;}
C Llook(Lt*lexer,Z offset){Z pos=lexer->pos+offset;
  if(pos>=lexer->len)R 0;R lexer->source[pos];}
C Leat(Lt*lexer){if(lexer->pos>=lexer->len)R 0;R lexer->source[lexer->pos++];}
V LpT(Lt*lexer,enum Tkt tag,S text){Tkt*token=ma(SO(Tkt));
  token->tag=tag;
  token->text=text;
  Ap(lexer->tokens,token);}
Ar*guards;
jmp_buf*guard(){jmp_buf*lb=maa(SO(jmp_buf));
  Ap(guards,lb);R lb;}
jmp_buf*guarding(){R Ai(guards,-1);}
V unguard(){jmp_buf*lb=AP(guards);
  FR(lb);}
V fatal(S s){jmp_buf*lb;
  if((lb=guarding()))longjmp(*lb,1);
  fprintf(stderr,"|%s error\n",s);
  if(Iin)longjmp(Icp,1);
  exit(1);}
V Lerror(Lt*lexer,S s){fatal(s);}
V Llnum(Lt*lexer,B is_negative){Bt*buf=Bnew();
  if(is_negative)Bappend(buf,'-');
  if(Llook(lexer,0)=='.'){Bappend(buf,Leat(lexer));
    if(!(isdigit(Llook(lexer,0))))Lerror(lexer,"trailing-dot");}
  do{Bappend(buf,Leat(lexer));
    if(Llook(lexer,0)=='`'&&isdigit(Llook(lexer,1)))Leat(lexer);}WH(isdigit(Llook(lexer,0)));
  if(Llook(lexer,0)=='.'){Bappend(buf,Leat(lexer));
    if(!(isdigit(Llook(lexer,0))))Lerror(lexer,"trailing-dot");
    do{Bappend(buf,Leat(lexer));}WH(isdigit(Llook(lexer,0)));}
  LpT(lexer,T_NUM,Bread(buf));}
V Llex(Lt*lexer,S s){lexer->source=s;
  lexer->len=strlen(s);
  lexer->pos=0;
  lexer->tokens=An();
  WH(lexer->pos<lexer->len){C c=Llook(lexer,0);
    if(c=='/'&&!lexer->tokens->data)BR;
    if(isspace(c)){Leat(lexer);
      if(Llook(lexer,0)=='/')BR;}elif(c=='0'&&(Llook(lexer,1)=='x'||Llook(lexer,1)=='b'||Llook(lexer,1)=='o')){Leat(lexer);
      Bt*buf=Bnew();
      C b=Leat(lexer);
      Bappend(buf,b);
      cS base=b=='x'?"0123456789abcdefABCDEF":b=='b'?"01":"01234567";
      WH(strchr(base,Llook(lexer,0))!=N)Bappend(buf,Leat(lexer));
      LpT(lexer,T_BNUM,Bread(buf));}elif(isdigit(c)||c=='.'){Llnum(lexer,F);}elif(isalpha(c)){Bt*buf=Bnew();
      do{Bappend(buf,Leat(lexer));}WH(isalpha(Llook(lexer,0)));
      if(buf->used==1&&Llook(lexer,0)=='.'){Bappend(buf,Leat(lexer));
        LpT(lexer,T_PUNCT,Bread(buf));}else LpT(lexer,T_NAME,Bread(buf));}elif(c=='('||c==')'){Leat(lexer);
      LpT(lexer,c=='('?T_LPAR:T_RPAR,N);}elif(c=='\''){Bt*buf=Bnew();
      Leat(lexer);
      LOOP{if(lexer->pos>=lexer->len)Lerror(lexer,"unmatched-quote");
        if(Llook(lexer,0)=='\''){if(Llook(lexer,1)=='\''){Bappend(buf,Leat(lexer));
            Leat(lexer);CN;}
          Leat(lexer);BR;}
        Bappend(buf,Leat(lexer));}
      LpT(lexer,T_QUOTE,Bread(buf));}elif(ispunct(c)){C buf[3];
      buf[0]=Leat(lexer);
      buf[1]=0;
      if(Llook(lexer,0)=='.'||Llook(lexer,0)==':'){buf[1]=Leat(lexer);
        buf[2]=0;}
      if(strcmp(buf,"-")==0&&isdigit(Llook(lexer,0))){Llnum(lexer,T);CN;}
      LpT(lexer,T_PUNCT,sdup(buf));}else Lerror(lexer,"lex");}}
typedef struct _Tt Tt;
typedef struct _Tentry_t Tentry_t;
struct _Tentry_t{S key;
  P value;
  B is_deleted;};
struct _Tt{Tentry_t*entries;
  Z used;
  Z capacity;};
Tt*Tnew(void){Tt*table=ma(SO(Tt));
  table->used=0;
  table->capacity=TABLE_MIN_SIZE;
  table->entries=ma(table->capacity*SO(Tentry_t));R table;}
Z Tlength(Tt*table){R table->used;}
B Tempty(Tt*table){R table->used==0;}
static U64 MM86128(P key,const I len,U32 seed){const uint8_t*data=(const uint8_t*)key;
  const I nblocks=len/16;
  U32 h1=seed;
  U32 h2=seed;
  U32 h3=seed;
  U32 h4=seed;
  U32 c1=0x239b961b;
  U32 c2=0xab0e9789;
  U32 c3=0x38b34ae5;
  U32 c4=0xa1e38b93;
  const uint32_t*blocks=(const uint32_t*)(data+nblocks*16);
  for(I i=-nblocks;i;i++){U32 k1=blocks[i*4+0];
    U32 k2=blocks[i*4+1];
    U32 k3=blocks[i*4+2];
    U32 k4=blocks[i*4+3];
    k1*=c1;
    k1=ROTL32(k1,15);
    k1*=c2;
    h1^=k1;
    h1=ROTL32(h1,19);
    h1+=h2;
    h1=h1*5+0x561ccd1b;
    k2*=c2;
    k2=ROTL32(k2,16);
    k2*=c3;
    h2^=k2;
    h2=ROTL32(h2,17);
    h2+=h3;
    h2=h2*5+0x0bcaa747;
    k3*=c3;
    k3=ROTL32(k3,17);
    k3*=c4;
    h3^=k3;
    h3=ROTL32(h3,15);
    h3+=h4;
    h3=h3*5+0x96cd1c35;
    k4*=c4;
    k4=ROTL32(k4,18);
    k4*=c1;
    h4^=k4;
    h4=ROTL32(h4,13);
    h4+=h1;
    h4=h4*5+0x32ac3b17;}
  const uint8_t*tail=(const uint8_t*)(data+nblocks*16);
  U32 k1=0;
  U32 k2=0;
  U32 k3=0;
  U32 k4=0;
  SW(len & 15){CS 15:k4^=tail[14]<<16;
  CS 14:k4^=tail[13]<<8;
  CS 13:k4^=tail[12]<<0;
    k4*=c4;
    k4=ROTL32(k4,18);
    k4*=c1;
    h4^=k4;
  CS 12:k3^=tail[11]<<24;
  CS 11:k3^=tail[10]<<16;
  CS 10:k3^=tail[9]<<8;
  CS 9:k3^=tail[8]<<0;
    k3*=c3;
    k3=ROTL32(k3,17);
    k3*=c4;
    h3^=k3;
  CS 8:k2^=tail[7]<<24;
  CS 7:k2^=tail[6]<<16;
  CS 6:k2^=tail[5]<<8;
  CS 5:k2^=tail[4]<<0;
    k2*=c2;
    k2=ROTL32(k2,16);
    k2*=c3;
    h2^=k2;
  CS 4:k1^=tail[3]<<24;
  CS 3:k1^=tail[2]<<16;
  CS 2:k1^=tail[1]<<8;
  CS 1:k1^=tail[0]<<0;
    k1*=c1;
    k1=ROTL32(k1,15);
    k1*=c2;
    h1^=k1;}
  h1^=len;
  h2^=len;
  h3^=len;
  h4^=len;
  h1+=h2;
  h1+=h3;
  h1+=h4;
  h2+=h1;
  h3+=h1;
  h4+=h1;
  FMIX32(h1);
  FMIX32(h2);
  FMIX32(h3);
  FMIX32(h4);
  h1+=h2;
  h1+=h3;
  h1+=h4;
  h2+=h1;
  h3+=h1;
  h4+=h1;R(((U64)h2)<<32)| h1;}
static U32 HASH_SEED=0;
P Tget(Tt*table,S key){if(Tempty(table))R N;
  U64 hash=MM86128(key,strlen(key),HASH_SEED);
  Z index=hash%table->capacity;
  Z i=index;
  WH(table->entries[i].key){if(!table->entries[i].is_deleted&&strcmp(table->entries[i].key,key)==0)R table->entries[i].value;
    i++;
    if(i>=table->capacity)i=0;
    if(i==index)BR;}
  R N;}
B Thas(Tt*table,S key){if(Tempty(table))R F;
  U64 hash=MM86128(key,strlen(key),HASH_SEED);
  Z index=hash%table->capacity;
  Z i=index;
  WH(table->entries[i].key){if(!table->entries[i].is_deleted&&strcmp(table->entries[i].key,key)==0)R T;
    i++;
    if(i>=table->capacity)i=0;
    if(i==index)BR;}
  R F;}
static V Tentry_set(Tentry_t*entries,S key,P value,Z capacity,Z*used){U64 hash=MM86128(key,strlen(key),HASH_SEED);
  Z index=hash%capacity;
  Z i=index;
  WH(entries[i].key){if(strcmp(entries[i].key,key)==0){entries[i].value=value;
      if(entries[i].is_deleted){if(used)(*used)++;
        entries[i].is_deleted=F;}
      R;}elif(entries[i].is_deleted)BR;
    i++;
    if(i>=capacity)i=0;
    if(i==index)BR;}
  if(used)(*used)++;
  entries[i].key=key;
  entries[i].value=value;
  entries[i].is_deleted=F;}
Tt*Tset(Tt*table,S key,P value){if(table->used>=table->capacity){Z capacity=table->capacity+TABLE_MIN_SIZE;
    Tentry_t*entries=ma(capacity*SO(Tentry_t));
    for(Z i=0;i<table->capacity;i++){Tentry_t entry=table->entries[i];
      if(entry.key&&!entry.is_deleted)Tentry_set(entries,entry.key,entry.value,capacity,N);}
    FR(table->entries);
    table->entries=entries;
    table->capacity=capacity;}
  Tentry_set(table->entries,key,value,table->capacity,&table->used);R table;}
B Tdelete(Tt*table,S key){U64 hash=MM86128(key,strlen(key),HASH_SEED);
  Z index=hash%table->capacity;
  Z i=index;
  WH(table->entries[i].key){if(!table->entries[i].is_deleted&&strcmp(table->entries[i].key,key)==0){table->entries[i].value=N;
      table->entries[i].is_deleted=T;
      table->used--;
      if(table->capacity>TABLE_MIN_SIZE&&table->used<=table->capacity-TABLE_MIN_SIZE){Z capacity=table->capacity-TABLE_MIN_SIZE;
        Tentry_t*entries=ma(capacity*SO(Tentry_t));
        for(Z i=0;i<table->capacity;i++){Tentry_t entry=table->entries[i];
          if(entry.key&&!entry.is_deleted)Tentry_set(entries,entry.key,entry.value,capacity,N);}
        FR(table->entries);
        table->entries=entries;
        table->capacity=capacity;}
      R T;}
    i++;
    if(i>=table->capacity)i=0;
    if(i==index)BR;}
  R F;}
typedef struct _Vt Vt;
typedef struct _St St;
typedef struct _vt vt;
struct _St{Tt*env;
  Ar*args;
  Ar*selfrefs;
  Vt*nil;
  Vt*udf;
  Vt*unit;
  vt*at;
  B bn;};
struct _vt{S name;
  UI rank[3];
  Ar*bonds;
  B mark;
  B is_fun;
  Vt*(*monad)(St*,vt*,Vt*);
  Vt*(*dyad)(St*,vt*,Vt*,Vt*);};
typedef struct{S name;
  vt*(*adverb)(St*,Vt*);
  vt*(*conjunction)(St*,Vt*,Vt*);}advt;
struct _Vt{enum Vtag_t{ARRAY,VERB,SYM,NUM,CHAR,NIL,UDF}tag;
  union{Ar*array;
    vt*verb;
    S symbol;
    D number;
    UC _char;}val;};
vt*vnew(){vt*verb=ma(SO(vt));R verb;}
Vt*Vnew(enum Vtag_t tag){Vt*val;
  if(tag>SYM)val=maa(SO(Vt));
  else val=ma(SO(Vt));
  val->tag=tag;R val;}
Vt*VnC(enum Vtag_t tag){Vt*val=mau(SO(Vt));
  val->tag=tag;R val;}
Vt*_UNIT;
Vt*Vna(Ar*array){if(!array->data){FR(array);R _UNIT;}
  Vt*val=Vnew(ARRAY);
  val->val.array=array;R val;}
Tt*VCACHE;
Vt*Vnv(vt*verb){Vt*val;
  if((val=Tget(VCACHE,verb->name)))R val;
  val=Vnew(VERB);
  val->val.verb=verb;R val;}
Tt*SCACHE;
Vt*Vny(S symbol){Vt*val;
  if((val=Tget(SCACHE,symbol)))R val;
  val=VnC(SYM);
  val->val.symbol=symbol;
  Tset(SCACHE,symbol,val);R val;}
Vt*_NAN,*INF,*NINF;
Vt*NNUMS[8];
Vt*NUMS[256];
Vt*CHARS[256];
Vt*Vnn(D number){if(isnan(number))R _NAN;
  elif(number==INFINITY)R INF;
  elif(number==-INFINITY)R NINF;
  elif(number>=0&&number<256&&number==(D)((Z)number))R NUMS[(Z)number];
  elif(number<0&&number>=-8&&fabs(number)==(D)((Z)fabs(number)))R NNUMS[((Z)fabs(number))-1];
  Vt*val=Vnew(NUM);
  val->val.number=number;R val;}
B Veq(Vt*x,Vt*y){if(xt!=yt)R F;
  SW(xt){CS ARRAY:{Ar*tx=xa;
    Ar*ty=ya;
    if(tx->length==0&&ty->length==0)BR;
    if(tx->length!=ty->length)R F;
    for(Z i=0;i<tx->length;i++)if(!Veq(tx->data[i],ty->data[i]))R F;}
  CS VERB:R strcmp(xV->name,xV->name)==0;
  CS SYM:R strcmp(xY,yY)==0;
  CS NUM:if(isnan(xn)&&isnan(yn))BR;R xn==yn;
  CS CHAR:R x==y;
  CS NIL:CS UDF:BR;}
  R T;}
B Cap(Ar*a){for(Z i=0;i<a->length;i++){Vt*v=a->data[i];
    if(v->tag!=CHAR||!isprint(v->val._char))R F;}
  R T;}
B Aap(Ar*a){for(Z i=0;i<a->length;i++){Vt*v=a->data[i];
    if(v->tag!=ARRAY)R F;}
  R T;}
B nonar(Ar*a){if(!a->data)R T;
  for(Z i=1;i<a->length;i++){Vt*v=a->data[i];
    if(v->tag==ARRAY)R F;}
  R T;}
B matp(Ar*a){if(a->length<2)R F;
  Z rwl=((Vt*)a->data[0])->val.array->length;
  if(rwl<1)R F;
  for(Z i=0;i<a->length;i++){Vt*v=a->data[i];
    if(v->tag!=ARRAY||v->val.array->length!=rwl||!nonar(v->val.array)||Cap(v->val.array))R F;}
  R T;}
S Vshow(Vt*v);
S show_array(Vt*v){if(v->tag!=ARRAY)R Vshow(v);
  Ar*t=v->val.array;
  if(!t->data)R sdup("()");
  Bt*buf=Bnew();
  if(t->length==1){Bappend(buf,',');
    S ts=Vshow(t->data[0]);
    BappendS(buf,ts);
    FR(ts);R Bread(buf);}
  if(Cap(t)){for(Z i=0;i<t->length;i++)Bappend(buf,((Vt*)t->data[i])->val._char);R Bread(buf);}
  if(!Aap(t))for(Z i=0;i<t->length;i++){S ts=Vshow(t->data[i]);
      BappendS(buf,ts);
      FR(ts);
      if(i!=t->length-1)Bappend(buf,' ');}
  elif(matp(t)){Z rwl=0;
    Z pad=0;
    Z padl=0;
    Ar*ss=An();
    for(Z i=0;i<t->length;i++){Vt*rw=t->data[i];
      Ar*rwt=rw->val.array;
      if(rwl<1)rwl=rwt->length;
      for(Z j=0;j<rwt->length;j++){S s=Vshow(rwt->data[j]);
        Z z=strlen(s);
        if(z>pad)pad=z;
        if(j==0&&z>padl)padl=z;
        Ap(ss,s);}}
    Z k=0;
    for(Z i=0;i<ss->length;i++){S s=ss->data[i];
      Z mp=(k==0?padl:pad)-strlen(s);
      WH(mp--)Bappend(buf,' ');
      BappendS(buf,s); 
      FR(s);
      if(i!=ss->length-1){if(k==rwl-1){k=0;
          Bappend(buf,'\n');}else{Bappend(buf,' ');
          k++;}}}
    FR(ss->data);
    FR(ss);}
  else for(Z i=0;i<t->length;i++){Vt*rw=t->data[i];
      S ts=show_array(rw);
      BappendS(buf,ts);
      FR(ts);
      if(i!=t->length-1)Bappend(buf,'\n');}
  R Bread(buf);}
S Vshow(Vt*v){SW(v->tag){CS ARRAY:R show_array(v);
  CS VERB:R sdup(v->val.verb->name);
  CS SYM:R sdup(v->val.symbol);
  CS NUM:{C buf[128];
    snprintf(buf,SO(buf),"%.15g",vn);R sdup(buf);}
  CS CHAR:{if(!isprint(v->val._char)){C buf[16];
      snprintf(buf,SO(buf),"4t.%d",v->val._char);R sdup(buf);}
    C buf[2];
    buf[0]=v->val._char;
    buf[1]=0;R sdup(buf);}
  CS NIL:R sdup("nil");
  CS UDF:R sdup("udf");}
  R sdup("<?>");}
S Vstr(Vt*v){if(v->tag==ARRAY&&v->val.array->length==1&&((Vt*)v->val.array->data[0])->tag==CHAR)R Vshow(v->val.array->data[0]);R Vshow(v);}
D Vnum(Vt*v){if(v->tag==CHAR)R v->val._char;R vn;}
B VTp(Vt*x){SW(xt){CS ARRAY:R xal!=0;
  CS NUM:CS CHAR:R Vnum(x)!=0;
  CS NIL:CS UDF:R F;
  default:R T;}}
vt*Gv(S s);
St*Sn(void){St*st=ma(SO(St));
  st->env=Tnew();
  st->args=An();
  st->selfrefs=An();
  st->nil=Vnew(NIL);
  st->udf=Vnew(UDF);
  st->unit=_UNIT;
  st->at=Gv("@");R st;}
V Serror(St*st,S e){fprintf(stderr,"%s error\n",e);
  exit(1);}
Vt*eR(St*st,vt*f,Vt*x,UI d,UI rm){if(!f->monad)R st->udf;
  if(d>=rm||xt!=ARRAY){if(f->mark)Ap(st->selfrefs,f);
    Vt*r=f->monad(st,f,x);
    if(f->mark)AP(st->selfrefs);R r;}
  Ar*t=xa;
  if(!t->data)R x;
  Ar*l=Ank(t->length);
  for(Z i=0;i<t->length;i++)l->data[i]=eR(st,f,t->data[i],d+1,rm);R Vna(l);}
Vt*apM(St*st,Vt*f,Vt*x){if(f->tag!=VERB)R st->udf;
  if(!f->val.verb->monad)R st->udf;R eR(st,f->val.verb,x,0,f->val.verb->rank[0]);}
Vt*tgth(St*st,vt*f,Vt*x,Vt*y,UI dl,UI dr,UI rl,UI rr){if(!f->dyad)R st->udf;
  if(dl>=rl&&dr>=rr){if(f->mark)Ap(st->selfrefs,f);
    Vt*r=f->dyad(st,f,x,y);
    if(f->mark)AP(st->selfrefs);R r;}
  if(dl<rl&&dr<rr&&xt==ARRAY&&yt==ARRAY){Ar*tx=xa;
    Ar*ty=ya;
    if(!tx->data||!ty->data)R !tx->data?x:y;
    Ar*t=Ank(ty->length<tx->length?ty->length:tx->length);
    for(Z i=0;i<tx->length;i++){if(i>=ty->length)BR;
      t->data[i]=tgth(st,f,tx->data[i],ty->data[i],dl+1,dr+1,rl,rr);}
    R Vna(t);}elif((xt!=ARRAY||dl>=rl)&&yt==ARRAY&&dr<rr){Ar*ty=ya;
    if(!ty->data)R y;
    Ar*t=Ank(ty->length);
    for(Z i=0;i<ty->length;i++)t->data[i]=tgth(st,f,x,ty->data[i],dl,dr+1,rl,rr);R Vna(t);}elif((yt!=ARRAY||dr>=rr)&&xt==ARRAY&&dl<rl){Ar*tx=xa;
    if(!tx->data)R x;
    Ar*t=Ank(tx->length);
    for(Z i=0;i<tx->length;i++)t->data[i]=tgth(st,f,tx->data[i],y,dl+1,dr,rl,rr);R Vna(t);}
  if(f->mark)Ap(st->selfrefs,f);
  Vt*r=f->dyad(st,f,x,y);
  if(f->mark)AP(st->selfrefs);R r;}
Vt*apD(St*st,Vt*f,Vt*x,Vt*y){if(f->tag!=VERB)R st->nil;R tgth(st,f->val.verb,x,y,0,0,f->val.verb->rank[1],f->val.verb->rank[2]);}
typedef struct _Nt Nt;
struct _Nt{enum Ntag_t{N_STRAND,N_LITERAL,N_INDEX1,N_INDEX2,N_FUN,N_MONAD,N_DYAD,N_ADV,N_CONJ,N_PARTIAL_CONJ,N_FORK,N_HOOK,N_BOND,N_OVER,N_BIND}tag;
  advt*av;
  Vt*v;
  Ar*l;
  Nt*a;
  Nt*b;
  Nt*c;
  Z dp;};
S Nshow(Nt*n){SW(n->tag){CS N_STRAND:{Bt*buf=Bnew();
      for(Z i=0;i<n->l->length;i++){if(i!=0)BappendS(buf,",:");
        S s=Nshow(n->l->data[i]);
        BappendS(buf,s);
        FR(s);}
      R Bread(buf);}
    CS N_LITERAL:R Vshow(n->v);
    CS N_INDEX1:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      Bappend(buf,' ');
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_INDEX2:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      Bappend(buf,' ');
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);
      Bappend(buf,' ');
      s=Nshow(n->c);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_FUN:{Bt*buf=Bnew();
      Bappend(buf,':');
      S s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_MONAD:CS N_HOOK:CS N_BOND:CS N_OVER:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_DYAD:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      s=Nshow(n->c);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_ADV:CS N_PARTIAL_CONJ:{Bt*buf=Bnew();
      S s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      BappendS(buf,n->av->name);R Bread(buf);}
    CS N_CONJ:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      BappendS(buf,n->av->name);
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_FORK:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);
      s=Nshow(n->c);
      BappendS(buf,s);
      FR(s);R Bread(buf);}
    CS N_BIND:{S s;
      Bt*buf=Bnew();
      s=Nshow(n->a);
      BappendS(buf,s);
      FR(s);
      Bappend(buf,':');
      s=Nshow(n->b);
      BappendS(buf,s);
      FR(s);R Bread(buf);}}
  R sdup("<?>");}
Vt*_fork_m(St*st,vt*self,Vt*x){vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  vt*h=Ai(self->bonds,2);
  Vt*l=eR(st,f,x,0,f->rank[0]);
  Vt*r=eR(st,h,x,0,f->rank[0]);R tgth(st,g,l,r,0,0,g->rank[1],g->rank[2]);}
Vt*_fork_d(St*st,vt*self,Vt*x,Vt*y){vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  vt*h=Ai(self->bonds,2);
  Vt*l=eR(st,f,x,0,f->rank[0]);
  Vt*r=eR(st,h,y,0,f->rank[0]);R tgth(st,g,l,r,0,0,g->rank[1],g->rank[2]);}
Vt*_hook_m(St*st,vt*self,Vt*x){vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  Vt*r=eR(st,g,x,0,g->rank[0]);R eR(st,f,r,0,f->rank[0]);}
Vt*_hook_d(St*st,vt*self,Vt*x,Vt*y){vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  Vt*r=tgth(st,g,x,y,0,0,g->rank[1],g->rank[2]);R eR(st,f,r,0,f->rank[0]);}
Vt*_bond_m(St*st,vt*self,Vt*x){vt*f=Ai(self->bonds,0);
  Vt*g=Ai(self->bonds,1);R tgth(st,f,g,x,0,0,f->rank[1],f->rank[2]);}
Vt*_bond_d(St*st,vt*self,Vt*x,Vt*y){vt*f=Ai(self->bonds,0);
  Vt*g=Ai(self->bonds,1);
  Vt*r=tgth(st,f,x,y,0,0,f->rank[1],f->rank[2]);R tgth(st,f,x,r,0,0,f->rank[1],f->rank[2]);}
Vt*_over_m(St*st,vt*self,Vt*x){Vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  vt*h=Ai(self->bonds,2);
  Vt*l=eR(st,h,x,0,h->rank[0]);R tgth(st,g,f,l,0,0,g->rank[1],g->rank[2]);}
Vt*_over_d(St*st,vt*self,Vt*x,Vt*y){Vt*f=Ai(self->bonds,0);
  vt*g=Ai(self->bonds,1);
  vt*h=Ai(self->bonds,2);
  Vt*l=tgth(st,h,x,y,0,0,h->rank[1],h->rank[2]);R tgth(st,g,f,l,0,0,g->rank[1],g->rank[2]);}
B nca(Nt*node,unsigned int*argc){if(!node)R F;
  if(node->tag==N_LITERAL&&node->v->tag==SYM&&strcmp(node->v->val.symbol,"y")==0){*argc=2;R T;}elif(node->tag==N_LITERAL&&node->v->tag==SYM&&strcmp(node->v->val.symbol,"x")==0){if(*argc<2)*argc=1;}elif(node->tag==N_MONAD||node->tag==N_CONJ||node->tag==N_HOOK||node->tag==N_BOND||node->tag==N_INDEX1){if(nca(node->a,argc))R T;
    if(nca(node->b,argc))R T;}elif(node->tag==N_DYAD||node->tag==N_FORK||node->tag==N_OVER||node->tag==N_INDEX2){if(nca(node->a,argc))R T;
    if(nca(node->b,argc))R T;
    if(nca(node->c,argc))R T;}elif(node->tag==N_ADV){if(nca(node->a,argc))R T;}elif(node->tag==N_STRAND){Ar*t=node->l;
    for(Z i=0;i<t->length;i++)if(nca(t->data[i],argc))R T;}elif(node->tag==N_BIND){if(nca(node->b,argc))R T;}
  R F;}
Vt*Swalk(St*st,Nt*node);
Vt*_const_m(St*st,vt*self,Vt*x){R Swalk(st,self->bonds->data[0]);}
Vt*_const_d(St*st,vt*self,Vt*x,Vt*y){R Swalk(st,self->bonds->data[0]);}
Vt*_constv_m(St*st,vt*self,Vt*x){R self->bonds->data[0];}
Vt*_constv_d(St*st,vt*self,Vt*x,Vt*y){R self->bonds->data[0];}
Vt*_fun_m(St*st,vt*self,Vt*x){Ar*args=An();
  Ap(args,x);
  Ap(args,self);
  Ap(st->args,args);
  Vt*r=Swalk(st,self->bonds->data[0]);
  AP(st->args);
  FR(args);R r;}
Vt*_fun_d(St*st,vt*self,Vt*x,Vt*y){Ar*args=An();
  Ap(args,x);
  Ap(args,y);
  Ap(args,self);
  Ap(st->args,args);
  Vt*r=Swalk(st,self->bonds->data[1]);
  AP(st->args);
  FR(args);R r;}
Vt*_partial_conjunction(St*st,vt*self,Vt*x){advt*av=self->bonds->data[0];
  Vt*a=self->bonds->data[1];R Vnv(av->conjunction(st,a,x));}
Nt*Nn1(enum Ntag_t tag,Nt*a);
Vt*Swalk(St*st,Nt*node){if(!node)R st->nil;
  SW(node->tag){CS N_STRAND:{Ar*t=Ac(node->l);
    for(Z i=0;i<t->length;i++)t->data[i]=Swalk(st,t->data[i]);R Vna(t);}
  CS N_LITERAL:{Vt*v=node->v;
    Vt*t=N;
    if(v->tag==SYM){S n=v->val.symbol;
      if(st->args->data){Ar*args=Ai(st->args,-1);
        Z argc=args->length-1;
        if(argc==2&&strcmp(n,"y")==0)R args->data[1];
        elif(strcmp(n,"x")==0)R args->data[0];}
      if((t=Tget(st->env,n)))R t;
      if(strcmp(n,"T")==0)R Vnn(time(N));}
    R v;}
  CS N_INDEX1:R tgth(st,st->at,Swalk(st,node->a),Swalk(st,node->b),0,0,st->at->rank[1],st->at->rank[2]);
  CS N_INDEX2:R tgth(st,st->at,tgth(st,st->at,Swalk(st,node->a),Swalk(st,node->b),0,0,st->at->rank[1],st->at->rank[2]),Swalk(st,node->c),0,0,st->at->rank[1],st->at->rank[2]);
  CS N_FUN:{UI argc=0;
    nca(node->a,&argc);
    vt*nv=vnew();
    if(argc>0)nv->is_fun=T;
    nv->bonds=An();
    S s=Nshow(node->a);
    Z z=strlen(s)+2;
    nv->name=ma(z);
    snprintf(nv->name,z,":%s",s);
    FR(s);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    if(argc==0){Ap(nv->bonds,node->a);
      nv->monad=_const_m;
      nv->dyad=_const_d;}elif(argc==1){Ap(nv->bonds,node->a);
      nv->monad=_fun_m;
      nv->dyad=N;}else{nv->monad=N;
      Ap(nv->bonds,st->udf);
      Ap(nv->bonds,node->a);
      nv->dyad=_fun_d;}
    R Vnv(nv);}
  CS N_MONAD:R apM(st,Swalk(st,node->a),Swalk(st,node->b));
  CS N_DYAD:R apD(st,Swalk(st,node->a),Swalk(st,node->b),Swalk(st,node->c));
  CS N_ADV:{Vt*v=Swalk(st,node->a);
    vt*nv=node->av->adverb(st,v);
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_CONJ:{Vt*v1=Swalk(st,node->a);
    Vt*v2=Swalk(st,node->b);
    vt*nv=node->av->conjunction(st,v1,v2);
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_PARTIAL_CONJ:{vt*nv=vnew();
    Vt*a=Swalk(st,node->a);
    S r=Vshow(a);
    Z l=strlen(r)+strlen(node->av->name)+1;
    nv->name=ma(l);
    snprintf(nv->name,l,"%s%s",r,node->av->name);
    FR(r);
    nv->bonds=An();
    Ap(nv->bonds,node->av);
    Ap(nv->bonds,a);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_partial_conjunction;
    nv->dyad=N;
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_FORK:{Vt*_f=Swalk(st,node->a);
    if(_f->tag!=VERB)R st->udf;
    Vt*_g=Swalk(st,node->b);
    if(_g->tag!=VERB)R st->udf;
    Vt*_h=Swalk(st,node->c);
    if(_h->tag!=VERB)R st->udf;
    vt*f=_f->val.verb;
    vt*g=_g->val.verb;
    vt*h=_h->val.verb;
    vt*nv=vnew();
    nv->bonds=Ank(3);
    nv->bonds->data[0]=f;
    nv->bonds->data[1]=g;
    nv->bonds->data[2]=h;
    Z l=strlen(f->name)+strlen(g->name)+strlen(h->name)+1;
    nv->name=ma(l);
    snprintf(nv->name,l,"%s%s%s",f->name,g->name,h->name);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_fork_m;
    nv->dyad=_fork_d;
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_HOOK:{Vt*_f=Swalk(st,node->a);
    if(_f->tag!=VERB)R st->udf;
    Vt*_g=Swalk(st,node->b);
    if(_g->tag!=VERB)R st->udf;
    vt*f=_f->val.verb;
    vt*g=_g->val.verb;
    vt*nv=vnew();
    nv->bonds=Ank(2);
    nv->bonds->data[0]=f;
    nv->bonds->data[1]=g;
    Z l=strlen(f->name)+strlen(g->name)+1;
    nv->name=ma(l);
    snprintf(nv->name,l,"%s%s",f->name,g->name);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_hook_m;
    nv->dyad=_hook_d;
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_BOND:{Vt*_f=Swalk(st,node->a);
    if(_f->tag!=VERB)R st->udf;
    Vt*g=Swalk(st,node->b);
    vt*f=_f->val.verb;
    vt*nv=vnew();
    nv->bonds=Ank(2);
    nv->bonds->data[0]=f;
    nv->bonds->data[1]=g;
    S r=Vshow(g);
    Z l=strlen(r)+strlen(f->name)+1;
    nv->name=ma(l);
    snprintf(nv->name,l,"%s%s",r,f->name);
    FR(r);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_bond_m;
    nv->dyad=_bond_d;
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_OVER:{Vt*f=Swalk(st,node->a);
    Vt*_g=Swalk(st,node->b);
    if(_g->tag!=VERB)R st->udf;
    Vt*_h=Swalk(st,node->c);
    if(_h->tag!=VERB)R st->udf;
    vt*g=_g->val.verb;
    vt*h=_h->val.verb;
    vt*nv=vnew();
    nv->bonds=Ank(3);
    nv->bonds->data[0]=f;
    nv->bonds->data[1]=g;
    nv->bonds->data[2]=h;
    S r=Vshow(f);
    Z l=strlen(r)+strlen(g->name)+strlen(h->name)+1;
    nv->name=ma(l);
    snprintf(nv->name,l,"%s%s%s",r,g->name,h->name);
    FR(r);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_over_m;
    nv->dyad=_over_d;
    if(node->dp<2)nv->mark=T;R Vnv(nv);}
  CS N_BIND:{Vt*l=node->a->v;
    Nt*b=node->b;
    if(st->bn||st->args->data||node->dp!=0){Tset(st->env,l->val.symbol,Swalk(st,b));BR;}
    UI argc=0;
    nca(b,&argc);
    if(argc!=0)b=Nn1(N_FUN,b);
    B t=st->bn;
    st->bn=T;
    Vt*r=Swalk(st,b);
    st->bn=F;
    if(argc!=0){FR(r->val.verb->name);
      r->val.verb->name=l->val.symbol;}
    if(r->tag==VERB&&argc==0)r->val.verb->mark=T;
    Vt*ov=Tget(st->env,l->val.symbol);
    if(ov&&ov->tag==VERB&&ov->val.verb->is_fun&&r->tag==VERB&&r->val.verb->is_fun){if(!ov->val.verb->monad&&r->val.verb->monad){As(ov->val.verb->bonds,0,r->val.verb->bonds->data[0]);
        ov->val.verb->monad=r->val.verb->monad;BR;}
      if(!ov->val.verb->dyad&&r->val.verb->dyad){Ap(ov->val.verb->bonds,r->val.verb->bonds->data[1]);
        ov->val.verb->dyad=r->val.verb->dyad;BR;}}
    Tset(st->env,l->val.symbol,r);}BR;}
  R st->nil;}
Vt*vconst(St*st,vt*self,Vt*x){vt*nv=vnew();
  nv->bonds=Ank(1);
  nv->bonds->data[0]=x;
  S r=Vshow(x);
  Z l=strlen(r)+2;
  nv->name=ma(l);
  snprintf(nv->name,l,":%s",r);
  nv->rank[0]=0;
  nv->rank[1]=0;
  nv->rank[2]=0;
  nv->monad=_constv_m;
  nv->dyad=_constv_d;R Vnv(nv);}
Vt*vbind(St*st,vt*self,Vt*x,Vt*y){if(xt==SYM){if(yt==VERB)yV->mark=T;
    Tset(st->env,xY,y);}
  R st->udf;}
Tt*Inverses;
Vt*vunbind(St*st,vt*self,Vt*x){if(xt==SYM){Tdelete(st->env,xY);R st->nil;}
  R st->udf;}
Vt*vobverse(St*st,vt*self,Vt*x,Vt*y){if(xt==VERB&&yt==VERB){vt*vx=xV;
    if(!yV->monad)
      R st->udf;
    if(vx->is_fun)R st->udf;
    if(Thas(Inverses,vx->name))R st->udf;  
    Tset(Inverses,vx->name,yV);R st->nil;}
  R st->udf;}
Vt*vflip(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R st->udf;
  if(!Aap(xa))R st->udf;
  Ar*r=An();
  Vt*c0=xad[0];
  Ar*c0t=c0->val.array;
  Z c0l=c0t->length;
  for(Z i=0;i<c0l;i++){Ar*nc=An();
    for(Z j=0;j<xal;j++){Vt*rw=xad[j];
      Ar*rwt=rw->val.array;
      if(!rwt->data)R st->udf;
      Vt*v=Ai(rwt,i);
      if(!v)v=rwt->data[0];
      Ap(nc,v);}
    Ap(r,Vna(nc));}
  R Vna(r);}
Vt*vplus(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(xt==CHAR||yt==CHAR)R Vnc(Vnum(x)+Vnum(y));R Vnn(Vnum(x)+Vnum(y));}
  R _NAN;}
Vt*vsign(St*st,vt*self,Vt*x){if(xt==NUM)R xn<0?NNUMS[0]:xn>0?NUMS[1]:NUMS[0];R _NAN;}
D gcd(D a,D b){if(b!=0)R gcd(b,fmod(a,b));
  else R fabs(a);}
Vt*vgcd(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(gcd(xn,yn));R _NAN;}
Vt*vsin(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(sin(xn));R _NAN;}
Vt*vsquare(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(xn*xn);R _NAN;}
Vt*vnegate(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(-xn);R _NAN;}
Vt*vminus(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(xt==CHAR||yt==CHAR)R Vnc(Vnum(x)-Vnum(y));R Vnn(Vnum(x)-Vnum(y));}
  R _NAN;}
Vt*vatan(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(atan(xn));R _NAN;}
Vt*vatan2(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(atan2(xn,yn));R _NAN;}
Vt*vfirst(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  if(!xad)R st->udf;R xad[0];}
Vt*vtimes(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(xt==CHAR||yt==CHAR)R Vnc(Vnum(x)*Vnum(y));R Vnn(Vnum(x)*Vnum(y));}
  R _NAN;}
D lcm(D a,D b){R(a*b)/gcd(a,b);}
U64 factorial(U64 n){U64 r=1;
  WH(n>0)r*=n--;R r;}
Vt*vfactorial(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(factorial((U64)fabs(xn)));R _NAN;}
Vt*vlcm(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(lcm(xn,yn));R _NAN;}
Vt*vdouble(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(xn*2);R _NAN;}
Vt*vreplicate(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM){Z k=fabs(xn);
    Ar*r=An();
    WH(k--)Ap(r,y);R Vna(r);}
  R st->udf;}
Vt*vreciprocal(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(1/xn);R _NAN;}
Vt*vdivide(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){D ny=yn;
    if(ny==0)R INF;R Vnn(xn/ny);}
  R _NAN;}
D npower(D base,I n){if(n<0)R npower(1/base,-n);
  elif(n==0)R 1.0;
  elif(n==1)R base;
  elif(n%2)R base*npower(base*base,n/2);
  else R npower(base*base,n/2);}
D nroot(D base,I n){if(n==1)R base;
  elif(n<=0||base<0)R NAN;
  else{D delta,x=base/n;
    do{delta=(base/npower(x,n-1)-x)/n;
      x+=delta;}WH(fabs(delta)>=1e-8);R x;}}
Vt*vsqrt(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(sqrt(xn));R _NAN;}
Vt*vroot(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(nroot(yn,xn));R _NAN;}
Vt*vhalve(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(xn/2);R _NAN;}
Vt*vidivide(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){D ny=yn;
    if(ny==0)R INF;R Vnn(trunc(xn/ny));}
  R _NAN;}
Vt*venlist(St*st,vt*self,Vt*x);
Vt*vpred(St*st,vt*self,Vt*x);
Vt*vrange(St*st,vt*self,Vt*x,Vt*y);
Vt*venum(St*st,vt*self,Vt*x){if(Veq(x,NUMS[1]))R venlist(st,N,NUMS[0]);
  elif(Veq(x,NUMS[0]))R st->unit;R vrange(st,self,NUMS[0],vpred(st,self,x));}
Vt*vmod(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){D ny=yn;
    if(ny==0)R _NAN;R Vnn(fmod(xn,ny));}
  R _NAN;}
Vt*vtake(St*st,vt*self,Vt*x,Vt*y);
Vt*vdrop(St*st,vt*self,Vt*x,Vt*y);
B spnp(D v){R isnan(v)||v==INFINITY||v==-INFINITY;}
Vt*vodometer(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(xal<2)R st->udf;
  Z p=1;
  Z xl=xal;
  for(Z i=0;i<xl;i++){Vt*it=xad[i];
    if(it->tag!=NUM||spnp(it->val.number))R st->udf;
    p*=(Z)(it->val.number);}
  if(p<1)R st->unit;
  uint64_t*lims=maa(SO(U64)*xl);
  for(Z i=0;i<xl;i++)lims[i]=(Z)(((Vt*)xad[i])->val.number);
  uint64_t**z=ma(SO(uint64_t*)*p);
  for(Z i=0;i<p;i++)z[i]=maa(SO(U64)*xl);
  for(Z i=0;i<p-1;i++){uint64_t*r=z[i];
    uint64_t*s=z[i+1];
    B carry=T;
    for(Z j=0;j<xl;j++){U64 a=xl-1-j;
      s[a]=r[a];
      if(carry){s[a]++;carry=F;}
      if(s[a]>=lims[a]){s[a]=0;carry=T;}}}
  FR(lims);
  Ar*r=Ank(p);
  for(Z i=0;i<p;i++){Ar*rw=Ank(xl);
    for(Z j=0;j<xl;j++)rw->data[j]=Vnn(z[i][j]);
    r->data[i]=Vna(rw);
    FR(z[i]);}
  FR(z);R Vna(r);}
Vt*vchunks(St*st,vt*self,Vt*x,Vt*y){if(xt!=NUM)R st->udf;
  if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R y;
  Ar*r=An();
  Z cl=fabs(xn);
  for(Z i=0;i<yal;i+=cl)Ap(r,vtake(st,N,Vnn(cl),vdrop(st,N,Vnn(i),y)));R Vna(r);}
Vt*vexp(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(exp(xn));R _NAN;}
Vt*vpower(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(pow(xn,yn));R _NAN;}
Vt*vnlog(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(log(xn));R _NAN;}
Vt*vlog(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(log(yn)/log(xn));R _NAN;}
I bits_needed(U32 value){I bits=0;
  for(I bit_test=16;bit_test>0;bit_test>>=1){if(value>>bit_test!=0){bits+=bit_test;
      value>>=bit_test;}}
  R bits+value;}
Vt*vbits(St*st,vt*self,Vt*x){if(xt==NUM){I n=xn;
    I bk=bits_needed(n);
    Ar*r=Ank(bk);
    for(I i=0;i<bk;i++)if((n &(1<<i))>>i)r->data[i]=NUMS[1];
      else r->data[i]=NUMS[0];R Vna(r);}
  R st->udf;}
Vt*vreverse(St*st,vt*self,Vt*x);
Vt*vbase(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){Z v=fabs(yn);
    Z b=fabs(xn);
    if(b<2)R st->udf;
    Ar*r=An();
    WH(v>0){Ap(r,Vnn(v%b));
      v/=b;}
    R vreverse(st,N,Vna(r));}
  R st->udf;}
SZ indexOf(Ar*l,Vt*x){if(!l->data)return-1;
  for(Z i=0;i<l->length;i++)if(Veq(l->data[i],x))R i;
  return-1;}
Vt*vgroup(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  Ar*r=An();
  Ar*is=An();
  for(Z i=0;i<xal;i++){Vt*v=xad[i];
    SZ n=indexOf(is,v);
    if(n<0){Ap(r,venlist(st,N,Vnn(i)));
      Ap(is,v);}else{Vt*tmp=Ai(r,n);
      Ap(tmp->val.array,Vnn(i));}}
  FR(is->data);
  FR(is);R Vna(r);}
Vt*vbuckets(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R y;
  if(yt!=ARRAY)y=venlist(st,N,x);
  elif(!yad)R y;
  Ar*r=An();
  Z mx=0;
  for(Z i=0;i<xal;i++){Vt*v=xad[i];
    if(v->tag!=NUM)BR;
    SZ j=vn;
    if(j>=0&&j>mx)mx=j;}
  for(Z i=0;i<mx+1;i++)Ap(r,An());
  if(!r->data){FR(r);R st->unit;}
  for(Z i=0;i<xal;i++){if(i>=yal)BR;
    Vt*v=xad[i];
    if(v->tag!=NUM)BR;
    SZ j=vn;
    if(j>=0){Ar*b=Ai(r,j);
      if(b)Ap(b,yad[i]);}}
  if(xal<yal){Ar*lb=An();
    for(Z i=xal;i<yal;i++)Ap(lb,yad[i]);
    Ap(r,lb);}
  for(Z i=0;i<r->length;i++)r->data[i]=Vna(r->data[i]);R Vna(r);}
Vt*vequals(St*st,vt*self,Vt*x,Vt*y){R Veq(x,y)?NUMS[1]:NUMS[0];}
Vt*vpermute(St*st,vt*self,Vt*x){if(xt!=ARRAY||xal<2)R x;
  Ar*permutation=Ac(xa);
  Z length=permutation->length;
  Ar*result=An();
  Ap(result,Ac(permutation));
  Ar*c=An();
  for(Z i=0;i<length;i++){Z*n=maa(SO(Z));
    Ap(c,n);}
  Z k;
  Ar*p;
  Z i=0;
  WH(i<length){Z*n=Ai(c,i);
    if((*n)<i){k=i%2&&(*n);
      p=Ai(permutation,i);
      As(permutation,i,Ai(permutation,k));
      As(permutation,k,p);
      *n=(*n)+1;
      i=1;
      Ap(result,Ac(permutation));}else{*n=0;
      i++;}}
  for(Z i=0;i<c->length;i++)FR(c->data[i]);
  FR(c->data);
  FR(c);
  
  FR(permutation->data);
  FR(permutation);
  for(Z i=0;i<result->length;i++)result->data[i]=Vna(result->data[i]);R Vna(result);}
Vt*voccurences(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  Ar*table=An();
  Ar*r=An();
  for(Z i=0;i<xal;i++){B f=F;
    Vt*it=xad[i];
    for(Z j=0;j<table->length;j++){Ar*p=table->data[j];
      if(Veq(p->data[0],it)){Z*n=p->data[1];
          *n=(*n)+1;
          Ap(r,Vnn(*n));
          f=T;BR;}}
    if(!f){Ar*p=Ank(2);
      p->data[0]=it;
      Z*n=maa(SO(Z));
      p->data[1]=n;
      Ap(table,p);
      Ap(r,NUMS[0]);}}
  for(Z i=0;i<table->length;i++){Ar*p=table->data[i];
    FR(p->data[1]);
    FR(p->data);
    FR(p);}
  FR(table->data);
  FR(table);R Vna(r);}
Vt*vmask(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*r=An();
  Vt*l=Vnn(yal);
  Z n=0;
  Z k=xal;
  for(Z i=0;i<k;i++){Vt*s=vtake(st,N,l,vdrop(st,N,Vnn(i),x));
    if(Veq(s,y)){n++;
      for(Z j=0;j<l->val.number;j++,i++)Ap(r,Vnn(n));
      i--;}else Ap(r,NUMS[0]);}
  R Vna(r);}
Vt*vclassify(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  Ar*table=An();
  Ar*r=An();
  for(Z i=0;i<xal;i++){B f=F;
    Vt*it=xad[i];
    for(Z j=0;j<table->length;j++){Ar*p=table->data[j];
      if(Veq(p->data[0],it)){Z*n=p->data[1];
        Ap(r,Vnn(*n));
        f=T;BR;}}
    if(!f){Ar*p=Ank(2);
      p->data[0]=it;
      Z*n=maa(SO(Z));
      *n=i++;
      p->data[1]=n;
      Ap(table,p);
      Ap(r,Vnn(*n));}}
  for(Z i=0;i<table->length;i++){Ar*p=table->data[i];
    FR(p->data[1]);
    FR(p->data);
    FR(p);}
  FR(table->data);
  FR(table);R Vna(r);}
Vt*vunbits(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  I n=0;
  for(Z i=0;i<xal;i++){if(VTp(xad[i]))n|=(int)1<<(int)i;
    else n &=~((int)1<<(int)i);}
  R Vnn(n);}
Vt*vunbase(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM){Z b=fabs(xn);
    if(b<2)R st->udf;
    if(yt!=ARRAY)y=venlist(st,N,y);
    Z n=0;
    if(!yad)R st->udf;
    for(Z i=0;i<yal;i++){Vt*v=yad[i];
      if(v->tag!=NUM)BR;
      Z k=fabs(vn);
      n=n*b+k;}
    R Vnn(n);}
  R st->udf;}
Vt*vnot(St*st,vt*self,Vt*x){R VTp(x)?NUMS[0]:NUMS[1];}
Vt*vnot_equals(St*st,vt*self,Vt*x,Vt*y){R !Veq(x,y)?NUMS[1]:NUMS[0];}
Vt*vpred(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(xn-1);
  elif(xt==CHAR)R Vnc(x->val._char-1);R _NAN;}
Vt*vless(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)<Vnum(y))R NUMS[1];R NUMS[0];}
  R _NAN;}
Vt*vfloor(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(floor(xn));R _NAN;}
I _compare_up(cP a,cP b){Vt*x=(*(Ar**)a)->data[0];
  Vt*y=(*(Ar**)b)->data[0];
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))R 1;
    elif(Vnum(x)<Vnum(y))return-1;R 0;}
  R 0;}
I _compare_down(cP a,cP b){Vt*x=(*(Ar**)a)->data[0];
  Vt*y=(*(Ar**)b)->data[0];
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))return-1;
    elif(Vnum(x)<Vnum(y))R 1;R 0;}
  R 0;}
Vt*_grade(Vt*x,B down){if(xt!=ARRAY||xal<2)R x;
  Ar*ps=Ank(xal);
  for(Z i=0;i<xal;i++){Ar*p=Ank(2);
    p->data[0]=xad[i];
    p->data[1]=Vnn(i);
    ps->data[i]=p;}
  qsort(ps->data,ps->length,SO(P ),down?_compare_down:_compare_up);
  for(Z i=0;i<ps->length;i++){Ar*p=ps->data[i];
    ps->data[i]=p->data[1];
    FR(p->data);
    FR(p);}
  R Vna(ps);}
Vt*vgradedown(St*st,vt*self,Vt*x){R _grade(x,T);}
Vt*vnudge_left(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)R venlist(st,N,x);
  elif(!yad)R y;
  elif(yal<2)R venlist(st,N,x);
  Ar*r=An();
  for(Z i=1;i<yal;i++)Ap(r,yad[i]);
  Ap(r,x);R Vna(r);}
Vt*vlesseq(St*st,vt*self,Vt*x,Vt*y){if(Veq(x,y))R NUMS[1];
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)<Vnum(y))R NUMS[1];R NUMS[0];}
  R _NAN;}
Vt*vsucc(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(xn+1);
  elif(xt==CHAR)R Vnc(x->val._char+1);R _NAN;}
Vt*vceil(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(ceil(xn));R _NAN;}
Vt*vgreater(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))R NUMS[1];R NUMS[0];}
  R _NAN;}
Vt*vgreatereq(St*st,vt*self,Vt*x,Vt*y){if(Veq(x,y))R NUMS[1];
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))R NUMS[1];R NUMS[0];}
  R _NAN;}
Vt*vgradeup(St*st,vt*self,Vt*x){R _grade(x,F);}
Vt*vnudge_right(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)R venlist(st,N,x);
  elif(!yad)R y;
  elif(yal<2)R venlist(st,N,x);
  Ar*r=An();
  Ap(r,x);
  for(Z i=0;i<yal-1;i++)Ap(r,yad[i]);R Vna(r);}
Vt*venlist(St*st,vt*self,Vt*x){Ar*l=An();
  Ap(l,x);R Vna(l);}
Vt*venpair(St*st,vt*self,Vt*x,Vt*y);
Vt*vjoin(St*st,vt*self,Vt*x,Vt*y){Ar*l;
  if(xt==ARRAY&&yt==ARRAY){if(!xad&&!yad)R st->unit;
    elif(!xad)R y;
    elif(!yad)R x;
    l=Ank(xal+yal);
    Z lp=0;
    for(Z i=0;i<xal;i++)l->data[lp++]=xad[i];
    for(Z i=0;i<yal;i++)l->data[lp++]=yad[i];}
  elif(xt==ARRAY&&yt!=ARRAY){if(!xad)R venlist(st,N,y);
    l=Ank(xal+1);
    Z lp=0;
    for(Z i=0;i<xal;i++)l->data[lp++]=xad[i];
    l->data[lp++]=y;}
  elif(xt!=ARRAY&&yt==ARRAY){if(!yad)R venlist(st,N,x);
    l=Ank(yal+1);
    Z lp=0;
    l->data[lp++]=x;
    for(Z i=0;i<yal;i++)l->data[lp++]=yad[i];}
  else R venpair(st,N,x,y);R Vna(l);}
Vt*venpair(St*st,vt*self,Vt*x,Vt*y){Ar*l=Ank(2);
  l->data[0]=x;
  l->data[1]=y;R Vna(l);}
Vt*vselfref1(St*st,vt*self,Vt*x){vt*v;
  if(st->args->data)v=Ai(Ai(st->args,-1),-1);
  elif(st->selfrefs->data)v=Ai(st->selfrefs,-1);
  else R st->udf;R eR(st,v,x,0,v->rank[0]);}
Vt*vselfref2(St*st,vt*self,Vt*x,Vt*y){vt*v;
  if(st->args->data)v=Ai(Ai(st->args,-1),-1);
  elif(st->selfrefs->data)v=Ai(st->selfrefs,-1);
  else R st->udf;R tgth(st,v,x,y,0,0,v->rank[1],v->rank[2]);}
Vt*vtake(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM){if(yt!=ARRAY){if(xn==0)R st->unit;
      else R x;}
    if(xn==0||!yad)R st->unit;
    B rev=xn<0;
    Z k=(Z)fabs(xn);
    Ar*r=Ank(yal<k?yal:k);
    Z p=0;
    if(rev)for(SZ i=k;i>0;i--){Vt*v=Ai(ya,-i);
        if(!v)CN;
        r->data[p++]=v;}
    else for(Z i=0;i<yal&&k;i++,k--)r->data[p++]=yad[i];R Vna(r);}
  R st->udf;}
Vt*vwhere(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  Ar*r=An();
  for(Z i=0;i<xal;i++){Vt*a=xad[i];
    if(a->tag!=NUM)BR;
    Z k=fabs(a->val.number);
    for(Z j=0;j<k;j++)Ap(r,Vnn(i));}
  R Vna(r);}
Vt*vcopy(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*tx=xa;
  Ar*ty=ya;
  if(!tx->data||!ty->data)R st->unit;
  Ar*r=An();
  for(Z i=0;i<tx->length;i++){Vt*a=tx->data[i];
    Vt*b=ty->data[i>=ty->length?ty->length-1:i];
    if(b->tag!=NUM)BR;
    Z k=fabs(b->val.number);
    for(Z i=0;i<k;i++)Ap(r,a);}
  R Vna(r);}
Vt*vnub(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R x;
  Ar*n=Ank(xal);
  Ar*r=An();
  for(Z i=0;i<xal;i++){B u=T;
    for(Z j=0;j<r->length;j++)if(Veq(xad[i],r->data[j])){u=F;BR;}
    if(u)Ap(r,xad[i]);
    n->data[i]=u?NUMS[1]:NUMS[0];}
  FR(r->data);
  FR(r);R Vna(n);}
Vt*vdrop(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM){if(yt!=ARRAY){if(xn==0)R y;
      else R st->unit;}
    if(xn==0)R y;
    if(!yad)R st->unit;
    B rev=xn<0;
    Z k=(Z)fabs(xn);
    if(k>=yal)R st->unit;
    if(rev){Z l=yal;
      if(k>=l)R st->unit;R vtake(st,N,Vnn(l-k),y);}
    Ar*r=Ank(yal-k);
    Z rp=0;
    for(Z i=k;i<yal;i++)r->data[rp++]=yad[i];R Vna(r);}
  R st->udf;}
Vt*vunique(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R x;
  Ar*r=An();
  for(Z i=0;i<xal;i++){B u=T;
    for(Z j=0;j<r->length;j++)if(Veq(xad[i],r->data[j])){u=F;BR;}
    if(u)Ap(r,xad[i]);}
  R Vna(r);}
Vt*vfind(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,self,y);
  elif(!yad)R st->unit;
  Ar*r=An();
  for(Z i=0;i<yal;i++)if(Veq(yad[i],x))Ap(r,Vnn(i));R Vna(r);}
Vt*vindexof(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,self,y);
  elif(!yad)R st->unit;
  SZ n=indexOf(ya,x);
  if(n<0)n=yal;R Vnn(n);}
Vt*vcount(St*st,vt*self,Vt*x){if(xt!=ARRAY)R NUMS[1];R Vnn(xal);}
V flatten(Vt*x,Ar*r){if(xt==ARRAY)
    for(Z i=0;i<xal;i++)flatten(xad[i],r);
  else Ap(r,x);}
Vt*vflatten(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R x;
  Ar*r=An();
  flatten(x,r);R Vna(r);}
Vt*vminand(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)<Vnum(y))R x;R y;}
  R _NAN;}
Vt*vreverse(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  if(xal<2)R x;
  Ar*r=Ank(xal);
  Z rp=0;
  for(SZ i=xal-1;i>=0;i--)r->data[rp++]=xad[i];R Vna(r);}
Vt*vmaxor(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))R x;R y;}
  R _NAN;}
Vt*vrotate(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||yal<2)R x;
  if(xt!=NUM)R st->udf;
  B rev=xn<0;
  Z k=fabs(xn);
  Ar*r=Ac(ya);
  for(Z i=0;i<k;i++){Vt*v;
    if(rev){v=r->data[0];
      for(Z j=0;j<r->length-1;j++)r->data[j]=r->data[j+1];
      r->data[r->length-1]=v;}
    else{v=r->data[r->length-1]; 
      for(Z j=r->length-1;j>0;j--)r->data[j]=r->data[j-1]; 
      r->data[0]=v;}}
  R Vna(r);}
Vt*vwindows(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R y;
  Z k=fabs(xn);
  Z l=yal;
  Ar*r=An();
  for(Z i=0;i<l;i++){if(i+k>l)BR;
    Ap(r,vtake(st,N,Vnn(k),vdrop(st,N,Vnn(i),y)));}
  R Vna(r);}
Z depthOf(Vt*x,Z d){if(xt==ARRAY){if(!xad)R 0;
    for(Z i=0;i<xal;i++){Z d2=depthOf(xad[i],d+1);
      if(d2>d)d=d2;}
    R d;}
  R 0;}
Vt*vdepth(St*st,vt*self,Vt*x){R Vnn(depthOf(x,1));}
Vt*vround(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(round(xn));R _NAN;}
Vt*vabs(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(fabs(xn));R _NAN;}
Vt*vtail(St*st,vt*self,Vt*x);
Vt*vat(St*st,vt*self,Vt*x,Vt*y){if(yt!=NUM)R st->udf;
  if(xt!=ARRAY){if(yn>-1&&yn<1)R x;
    else R st->udf;}
  if(!xad)R st->nil;
  Vt*v=Ai(xa,(SZ)yn);
  if(!v)R st->udf;R v;}
Vt*vmember(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,self,y);
  elif(!yad)R NUMS[0];
  for(Z i=0;i<yal;i++)if(Veq(yad[i],x))R NUMS[1];R NUMS[0];}
Vt*vshuffle(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(!xad)R x;
  Ar*r=Ac(xa);
  for(Z i=0;i<r->length;i++){Z j=rand()%r->length;
    Vt*tmp=r->data[i];
    r->data[i]=r->data[j];
    r->data[j]=tmp;}
  R Vna(r);}
Vt*vhead(St*st,vt*self,Vt*x){R vtake(st,N,NUMS[2],x);}
Vt*vbin(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(!xad)R x;
  if(yt!=ARRAY)y=venlist(st,self,x);
  elif(!yad)R y;
  Z xl=xal;
  Ar*bins=An();
  for(Z i=0;i<xl;i++){D s;
    D e;
    Vt*vs=xad[i];
    if(vs->tag==NUM)s=vs->val.number;
    elif(vs->tag==CHAR)s=vs->val._char;
    else R st->udf;
    Vt*ve=i==xl-1?Vnn(s+1):xad[i+1];
    if(ve->tag==NUM)e=fabs(ve->val.number);
    elif(ve->tag==CHAR)e=ve->val._char;
    else R st->udf;
    if(bins->data){Ar*pp=Ai(bins,-1);
      D*pe=pp->data[0];
      if(s<=(*pe))R st->udf;}
    D*sn=ma(SO(D));
    *sn=s;
    D*en=ma(SO(D));
    *en=e;
    Ar*p=An();
    Ap(p,sn);
    Ap(p,en);
    Ap(bins,p);}
  Z bl=bins->length;
  Ar*r=An();
  Z yl=yal;
  for(Z i=0;i<yl;i++){Vt*it=yad[i];
    D itv;
    if(it->tag==NUM)itv=it->val.number;
    elif(it->tag==CHAR)itv=it->val._char;
    else R st->udf;
    Ar*b=bins->data[0];
    D*s=b->data[0];
    if(itv<(*s)){Ap(r,NNUMS[0]);CN;}
    b=Ai(bins,-1);
    s=b->data[1];
    if(itv>=(*s)){Ap(r,Vnn(bl-1));CN;}
    D v=NAN;
    for(Z j=0;j<bl;j++){b=bins->data[j];
      D*s=b->data[0];
      D*e=b->data[1];
      if(itv>=(*s)&&itv<(*e)){v=j;BR;}}
    if(!isnan(v))Ap(r,Vnn(v));}
  for(Z j=0;j<bl;j++){Ar*b=bins->data[j];
    FR(b->data[0]);
    FR(b->data[1]);
    FR(b->data);
    FR(b);}
  FR(bins->data);
  FR(bins);R Vna(r);}
Vt*vtail(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  if(!xad)R st->udf;R Ai(xa,-1);}
Vt*vcut(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(!xad)R x;
  if(yt!=ARRAY)y=venlist(st,self,x);
  elif(!yad)R x;
  if(xal!=2)R st->udf;
  Vt*vs=xad[0];
  Vt*ve=xad[1];
  if(vs->tag!=NUM||ve->tag!=NUM)R st->udf;
  Z s=fabs(vs->val.number);
  Z e=fabs(ve->val.number);
  Ar*r=An();
  Z l=yal;
  Ar*pa=An();
  for(Z i=s;i<e&&i<l;i++){Vt*v=Ai(ya,i);
    if(!v)BR;
    Ap(pa,v);}
  Ar*pb=An();
  for(Z i=e;i<l;i++){Vt*v=Ai(ya,i);
    if(!v)BR;
    Ap(pb,v);}
  Ap(r,Vna(pa));
  Ap(r,Vna(pb));R Vna(r);}
Vt*vprefixes(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  Ar*r=An();
  for(Z i=0;i<xal;i++)Ap(r,vtake(st,N,Vnn(i),x));
  Ap(r,x);R Vna(r);}
Vt*vbehead(St*st,vt*self,Vt*x){R vdrop(st,N,NUMS[1],x);}
Vt*vcurtail(St*st,vt*self,Vt*x){R vdrop(st,N,NNUMS[0],x);}
Vt*vsuffixes(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  Ar*r=An();
  for(Z i=0;i<xal;i++)Ap(r,vdrop(st,N,Vnn(i),x));
  Ap(r,st->unit);R Vna(r);}
Vt*vleft(St*st,vt*self,Vt*x,Vt*y){R x;}
Vt*vsame(St*st,vt*self,Vt*x){R x;}
Vt*vright(St*st,vt*self,Vt*x,Vt*y){R y;}
Vt*vsymbol(St*st,vt*self,Vt*x){S s=Vstr(x);R Vny(s);}
Vt*vapply1(St*st,vt*self,Vt*x,Vt*y){R apM(st,x,y);}
Vt*vapply2(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||yal<2)R st->udf;R apD(st,x,yad[0],yad[1]);}
Vt*vshape(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R st->unit;
  if(!Aap(xa))R venlist(st,N,vcount(st,N,x));
  if(xal<2)R venlist(st,N,vshape(st,N,xad[0]));R venpair(st,N,vcount(st,N,x),vcount(st,N,xad[0]));}
Vt*vreshape(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R y;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R st->unit;
  Ar*r;
  if(xal<2){Vt*a=xad[0];
    if(a->tag!=NUM)R st->udf;
    Z k=fabs(a->val.number);
    Ar*t=An();
    flatten(y,t);
    r=Ank(k);
    for(Z i=0;i<k;i++)r->data[i]=t->data[i%t->length];}elif(xal>1){Vt*a=xad[0];
    if(a->tag!=NUM)R st->udf;
    Vt*b=xad[1];
    if(a->tag!=NUM)R st->udf;
    Z k=fabs(a->val.number);
    Z l=fabs(b->val.number);
    y=vreshape(st,self,venlist(st,N,Vnn(k*l)),y);
    r=An();
    Z yp=0;
    WH(k--){Ar*rw=An();
      for(Z i=0;i<l;i++)Ap(rw,yad[yp++]);
      Ap(r,Vna(rw));}}else R st->udf;R Vna(r);}
Vt*vrepr(St*st,vt*self,Vt*x){S s=Vshow(x);
  Ar*r=An();
  for(Z i=0;i<strlen(s);i++)Ap(r,Vnc(s[i]));
  FR(s);R Vna(r);}
S format(S template,Ar*replaces){Bt*text=Bnew();
  B skip=F;
  Z ri=0;
  Z tl=strlen(template);
  Z rl=replaces->length;
  for(Z i=0;i<tl;i++){C c=template[i];
    if(skip){Bappend(text,c);
      skip=F;CN;}
    if(c=='_'){S s=Vshow(Ai(replaces,ri));
      BappendS(text,s);
      FR(s);
      if(ri<rl-1)ri++;CN;}elif(c=='{'){Z bi=i;
      Bt*n=Bnew();
      i++;
      WH(i<tl&&template[i]!='}')Bappend(n,template[i++]);
      if(i>=tl||template[i]!='}'){FR(Bread(n));
        Bappend(text,'{');
        i=bi;CN;}
      S s=Bread(n);
      SZ ind=atoi(s);
      FR(s);
      Vt*v=Ai(replaces,ind);
      if(!v)CN;
      s=Vshow(v);
      BappendS(text,s);
      FR(s);CN;}elif(c=='~'){skip=T;CN;}
    Bappend(text,c);}
  R Bread(text);}
Vt*vformat(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,x);
  elif(!yad)R y;
  S fmt=Vshow(x);
  S s=format(fmt,ya);
  FR(fmt);
  Z z=strlen(s);
  Ar*r=Ank(z);
  for(Z i=0;i<z;i++)r->data[i]=CHARS[s[i]];R Vna(r);}
Vt*vinsert(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R y;
  Ar*r=Ank(yal*2-1);
  Z rp=0;
  for(Z i=0;i<yal;i++){r->data[rp++]=yad[i];
    if(i!=yal-1)r->data[rp++]=x;}
  R Vna(r);}
U64 fibonacci(U64 n){U64 a=0;
  U64 b=1;
  WH(n-->1){U64 t=a;
    a=b;
    b+=t;}
  R b;}
Vt*vfibonacci(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(fibonacci((U64)fabs(xn)));R _NAN;}
Vt*viota(St*st,vt*self,Vt*x){if(Veq(x,NUMS[1]))R venlist(st,N,NUMS[1]);
  elif(Veq(x,NUMS[0]))R st->unit;R vrange(st,self,NUMS[1],x);}
Vt*vrange(St*st,vt*self,Vt*x,Vt*y){if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(xt==NUM&&spnp(xn))R st->udf;
    if(yt==NUM&&spnp(yn))R st->udf;
    SZ s=Vnum(x);
    SZ e=Vnum(y);
    if(s==e)R venlist(st,N,x);
    Z p=0;
    Ar*r=Ank((s>e?s-e:e-s)+1);
    if(s>e)for(SZ i=s;i>=e;i--){if(xt==CHAR||yt==CHAR)r->data[p++]=CHARS[i];
        else r->data[p++]=Vnn(i);}
    else for(SZ i=s;i<=e;i++){if(xt==CHAR||yt==CHAR)r->data[p++]=CHARS[i];
        else r->data[p++]=Vnn(i);}
    R Vna(r);}
  R _NAN;}
Vt*vdeal(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  if(!xad)R st->udf;R xad[rand()%xal];}
Vt*vroll(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){Z k=fabs(xn);
    Z d=fabs(yn);
    Ar*r=Ank(k);
    for(Z i=0;i<k;i++)r->data[i]=Vnn(rand()%d);R Vna(r);}
  R st->udf;}
Vt*vtype(St*st,vt*self,Vt*x){R NUMS[xt];}
Vt*vcast(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM){I t=fabs(xn);
    if(yt==t)R y;
    SW(t){CS ARRAY:if(yt==SYM){S s=yY;
        Z z=strlen(s);
        Ar*r=Ank(z);
        for(Z i=0;i<z;i++)r->data[i]=CHARS[s[i]];R Vna(r);}BR;
    CS NUM:if(yt==CHAR)R Vnn(y->val._char);
      elif(yt==ARRAY&&Cap(ya)){Bt*buf=Bnew();
        for(Z i=0;i<yal;i++)Bappend(buf,((Vt*)yad[i])->val._char);
        S s=Bread(buf);
        D r=strtod(s,N);
        FR(s);R Vnn(r);}BR;
    CS CHAR:if(yt==NUM)R Vnc(yn);BR;}}
  R st->udf;}
Vt*vprint(St*st,vt*self,Vt*x){S s=Vstr(x);
  fprintf(stdout,"%s",s);
  FR(s);R st->nil;}
Vt*vprintln(St*st,vt*self,Vt*x){S s=Vstr(x);
  fprintf(stdout,"%s\n",s);
  FR(s);R st->nil;}
Vt*vputch(St*st,vt*self,Vt*x){if(xt!=CHAR)R st->udf;
  fputc(x->val._char,stdout);R st->nil;}
Vt*vexit(St*st,vt*self,Vt*x){if(xt!=NUM)R st->udf;
  I code=xn;
  exit(code);R st->nil;}
Vt*vread(St*st,vt*self,Vt*x){if(x==NUMS[0]){Bt*buf=Bnew();
    Z size=0;
    LOOP{I c=fgetc(stdin);
      if(c<0)BR;
      Bappend(buf,c);size++;}
    S s=Bread(buf);
    Ar*r=Ank(size);
    for(Z i=0;i<size;i++)r->data[i]=CHARS[s[i]];
    FR(s);R Vna(r);}
  elif(x==NUMS[1])R Vnc((UC)fgetc(stdin));
  elif(x==NUMS[2]){C line[512];
    if(!fgets(line,SO(line),stdin))R st->udf;
    Z z=strlen(line);
    Ar*r=Ank(z);
    for(Z i=0;i<z;i++)r->data[i]=CHARS[line[i]];R Vna(r);}
  S path=Vstr(x);
  FILE*fd=fopen(path,"rb");
  if(!fd){FR(path);R st->udf;}
  fseek(fd,0,SEEK_END);
  Z size=ftell(fd);
  fseek(fd,0,SEEK_SET);
  UC*buf=ma(size+1);
  size=fread(buf,SO(UC),size,fd);
  fclose(fd);
  FR(path);
  Ar*r=Ank(size);
  for(Z i=0;i<size;i++)r->data[i]=CHARS[buf[i]];
  FR(buf);R Vna(r);}
Vt*vwrite(St*st,vt*self,Vt*x,Vt*y){FILE*fd;
  S path=N;
  if(xt!=ARRAY)x=venlist(st,N,x);
  if(y==NUMS[0])fd=stderr;
  else{path=Vstr(y);
    fd=fopen(path,"wb");
    if(!fd){FR(path);R NNUMS[0];}}
  Z k=0;
  for(Z i=0;i<xal;i++){UC c;
    Vt*v=xad[i];
    if(v->tag==NUM)c=fabs(vn);
    elif(v->tag==CHAR)c=v->val._char;
    else BR;
    fputc(c,fd);
    k++;}
  fclose(fd);
  if(path)FR(path);R Vnn(k);}
Vt*vsystem(St*st,vt*self,Vt*x){S cmd=Vstr(x);
  FILE*pd;
  pd=popen(cmd,"r");
  if(!pd){FR(cmd);R st->udf;}
  UC*buffer=N;
  Z Bsize=0;
  Z Ballocated=0;
  Z bytes_received;
  UC chunk[1024];
  LOOP{bytes_received=fread(chunk,1,1024,pd);
    if(bytes_received==0)BR;
    Z head=Bsize;
    Bsize+=bytes_received;
    if(Bsize>Ballocated){Ballocated=Bsize;
      buffer=mrea(buffer,Ballocated);}    
    for(Z i=0;i<bytes_received;i++)buffer[head+i]=chunk[i];
    if(feof(pd))BR;}
  pclose(pd);
  FR(cmd);
  Ar*r=Ank(Bsize);
  for(Z i=0;i<Bsize;i++)r->data[i]=CHARS[buffer[i]];
  FR(buffer);R Vna(r);}
struct files_t{FILE*in;
  FILE*out;};
typedef struct files_t files_t;
struct files_chain_t{files_t files;
  pid_t pid;
  struct files_chain_t*next;};
typedef struct files_chain_t files_chain_t;
static files_chain_t*files_chain;
V _cleanup_pipe(int*pipe){close(pipe[0]);
  close(pipe[1]);}
static I _do_popen2(files_chain_t*link,cS command){I child_in[2];
  I child_out[2];
  if(0!=pipe(child_in))return-1;
  if(0!=pipe(child_out)){_cleanup_pipe(child_in);
    return-1;}
  pid_t cpid=link->pid=fork();
  if(0>cpid){_cleanup_pipe(child_in);
    _cleanup_pipe(child_out);
    return-1;}
  if(0==cpid){if(0>dup2(child_in[0],0)||0>dup2(child_out[1],1))_Exit(127);
    _cleanup_pipe(child_in);
    _cleanup_pipe(child_out);
    for(files_chain_t*p=files_chain;p;p=p->next){I fd_in=fileno(p->files.in);
      if(fd_in!=0)close(fd_in);
      I fd_out=fileno(p->files.out);
      if(fd_out!=1)close(fd_out);}
    execl("/bin/sh","sh","-c",command,(S )N);
    _Exit(127);}
  close(child_in[0]);
  close(child_out[1]);
  link->files.in=fdopen(child_in[1],"w");
  link->files.out=fdopen(child_out[0],"r");R 0;}
files_t*popen2(cS command){files_chain_t*link=(files_chain_t*)malloc(SO(files_chain_t));
  if(N==link)R N;
  if(0>_do_popen2(link,command)){free(link);R N;}
  link->next=files_chain;
  files_chain=link;R(files_t*)link;}
I pclose2(files_t*fp){files_chain_t**p=&files_chain;
  I found=0;
  WH(*p){if(*p==(files_chain_t*)fp){*p=(*p)->next;
      found=1;BR;}
    p=&(*p)->next;}
  if(!found)return-1;
  if(0>fclose(fp->out)){free((files_chain_t*)fp);
    return-1;}
  I status=-1;
  pid_t wait_pid;
  do{wait_pid=waitpid(((files_chain_t*)fp)->pid,&status,0);}WH(-1==wait_pid&&EINTR==errno);
  free((files_chain_t*)fp);
  if(wait_pid==-1)return-1;R status;}
Vt*vsystem2(St*st,vt*self,Vt*x,Vt*y){S cmd=Vstr(y);
  files_t*pd;
  pd=popen2(cmd);
  if(pd==N){FR(cmd);R st->udf;}
  for(Z i=0;i<xal;i++){UC c;
    Vt*v=xad[i];
    if(v->tag==NUM)c=fabs(vn);
    elif(v->tag==CHAR)c=v->val._char;
    else BR;
    fputc(c,pd->in);}
  fflush(pd->in);
  fclose(pd->in);
  UC*buffer=N;
  Z Bsize=0;
  Z Ballocated=0;
  Z bytes_received;
  UC chunk[1024];
  LOOP{bytes_received=fread(chunk,1,1024,pd->out);
    if(bytes_received==0)BR;
    Z head=Bsize;
    Bsize+=bytes_received;
    if(Bsize>Ballocated){Ballocated=Bsize;
      buffer=mrea(buffer,Ballocated);}    
    for(Z i=0;i<bytes_received;i++)buffer[head+i]=chunk[i];
    if(feof(pd->out))BR;}
  pclose2(pd);
  FR(cmd);
  Ar*r=Ank(Bsize);
  for(Z i=0;i<Bsize;i++)r->data[i]=CHARS[buffer[i]];
  FR(buffer);R Vna(r);}
Vt*vshl(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(((int)xn)<<((int)yn));R _NAN;}
Vt*vshr(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(((int)xn)>>((int)yn));R _NAN;}
Vt*vxor(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(((int)xn)^((int)yn));R _NAN;}
Vt*vband(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(((int)xn)&((int)yn));R _NAN;}
Ar*find_primes(U64 limit){B sieve[limit+1];
  for(U64 i=0;i<=limit;i++)sieve[i]=F;
  if(limit>2)sieve[2]=T;
  if(limit>3)sieve[3]=T;
  for(U64 x=1;x*x<=limit;x++)for(U64 y=1;y*y<=limit;y++){U64 n=(4*x*x)+(y*y);
      if(n<=limit&&(n%12==1||n%12==5))sieve[n]^=T;
      n=(3*x*x)+(y*y);
      if(n<=limit&&n%12==7)sieve[n]^=T;
      n=(3*x*x)-(y*y);
      if(x>y&&n<=limit&&n%12==11)sieve[n]^=T;}
  for(U64 r=5;r*r<=limit;r++)if(sieve[r])for(I i=r*r;i<=limit;i+=r*r)sieve[i]=F;
  Ar*r=An();
  for(U64 a=1;a<=limit;a++)if(sieve[a])Ap(r,Vnn(a));R r;}
Vt*vprimes(St*st,vt*self,Vt*x){if(xt==NUM&&!spnp(xn))R Vna(find_primes(fabs(xn)+1));R st->udf;}
Vt*vparts(St*st,vt*self,Vt*x,Vt*y){if(xt!=NUM)R st->udf;
  if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R y;
  if(spnp(xn)||xn<1)R y;
  Z np=fabs(xn);
  Ar*r=Ank(np);
  Z rp=0;
  for(SZ i=np;i>0;i--){Z k=ceil(((D)yal)/(D)i);
    r->data[rp++]=vtake(st,N,Vnn(k),y);
    y=vdrop(st,N,Vnn(k),y);}
  R Vna(r);}
Vt*vbor(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM)R Vnn(((int)xn)|((int)yn));R _NAN;}
Vt*vbnot(St*st,vt*self,Vt*x){if(xt==NUM)R Vnn(~(int)xn);R _NAN;}
Ar*prime_factors(D n){Ar*factors=An();
  D divisor=2;
  WH(n>=2){if(fmod(n,divisor)==0){Ap(factors,Vnn(divisor));
      n/=divisor;}else divisor++;}
  R factors;}
Vt*vfactors(St*st,vt*self,Vt*x){if(xt==NUM&&!spnp(xn))R Vna(prime_factors(xn));R st->udf;}
Vt*vcombine(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM&&!spnp(xn)&&!spnp(yn)){x=vbase(st,N,NUMS[10],x);
    y=vbase(st,N,NUMS[10],y);
    Vt*n=vjoin(st,N,x,y);R vunbase(st,N,NUMS[10],n);}
  R _NAN;}
Vt*voutof(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM&&!spnp(xn)&&!spnp(yn)){U64 a=(U64)fabs(xn);
    U64 b=(U64)fabs(yn);
    if(a==0)R NUMS[1];
    if(b==0)R NUMS[0];R Vnn(factorial(b)/(factorial(a)*(a>=b?1:factorial(b-a))));}
  R _NAN;}
Vt*vsort(St*st,vt*self,Vt*x){Vt*i=vgradeup(st,N,x);R tgth(st,st->at,x,i,0,0,st->at->rank[1],st->at->rank[2]);}
Vt*vunsort(St*st,vt*self,Vt*x){Vt*i=vgradedown(st,N,x);R tgth(st,st->at,x,i,0,0,st->at->rank[1],st->at->rank[2]);}
Vt*Srun(St*st,S program);
Vt*veval(St*st,vt*self,Vt*x){S s=Vstr(x);
  jmp_buf*lb=guard();
  if(setjmp(*lb)){unguard();
    FR(s);R st->udf;}
  Vt*v=Srun(st,s);
  FR(s);
  unguard();R v;}
V jkexec(St*st,FILE*fd,B isrepl,S*s);
Vt*vimport(St*st,vt*self,Vt*x){S path=Vstr(x);
  FILE*fd=fopen(path,"rb");
  if(!fd){FR(path);R st->udf;}
  S s=N;
  jkexec(st,fd,F,&s);
  if(s)FR(s);
  fclose(fd);
  FR(path);R st->nil;}
Vt*vforeign(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  S pth=Vstr(y);
  S lib;
  S sig;
  S fun;
  lib=strtok(pth,":");
  if(!lib)R st->udf;
  sig=strtok(N,":");
  if(!sig)R st->udf;
  fun=strtok(N,":");
  if(!fun)R st->udf;
  Z argc=strlen(sig);
  if(argc<1)R st->udf;
  argc--;
  if(argc!=xal)R st->udf;
  ffi_cif cif;
  ffi_type*ret;
  ffi_type*args[argc];
  P values[argc];
  P pool[argc];
  Z fc=0;
  P retv=N;
  C rett;
  Z retvsz=0;
  for(I i=0;i<strlen(sig);i++){ffi_type*t;
    P v;
    SW(sig[i]){CS '$':t=&ffi_type_pointer;BR;
      CS 'p':t=&ffi_type_pointer;BR;
      CS 'v':if(i!=0)goto cleanup;
        t=&ffi_type_void;BR;
      CS 'i':t=&ffi_type_sint;BR;
      CS 'l':t=&ffi_type_slong;BR;
      CS 'f':t=&ffi_type_float;BR;
      CS 'd':t=&ffi_type_double;BR;
      CS 'c':t=&ffi_type_uchar;BR;
      default:goto cleanup;}
    if(i==0){rett=sig[0];
      ret=t;
      SW(rett){CS '$':CS '@':retvsz=SO(S );BR;
        CS 'p':retvsz=SO(P );BR;
        CS 'v':retvsz=0;BR;
        CS 'i':retvsz=SO(int);BR;
        CS 'l':retvsz=SO(long);BR;
        CS 'f':retvsz=SO(float);BR;
        CS 'd':retvsz=SO(D);BR;
        CS 'c':retvsz=SO(UC);BR;}}else{SW(sig[i]){CS '$':CS '@':{Vt*vt=xad[i-1];
          pool[i-1]=Vstr(vt);
          v=pool[i-1];
          fc++;}BR;
        CS 'p':{P _pv;
          Vt*vt=xad[i-1];
          if(vt->tag!=NUM)goto cleanup;
          _pv=(P )(Z)fabs(vt->val.number);
          pool[i-1]=ma(SO(P ));
          memcpy(pool[i-1],&_pv,SO(P ));
          v=pool[i-1];
          fc++;}BR;
        CS 'i':{I _iv;
          Vt*vt=xad[i-1];
          if(vt->tag!=NUM)goto cleanup;
          _iv=(int)vt->val.number;
          pool[i-1]=ma(SO(int));
          memcpy(pool[i-1],&_iv,SO(int));
          v=pool[i-1];
          fc++;}BR;
        CS 'l':{long _lv;
          Vt*_vt=xad[i-1];
          if(_vt->tag!=NUM)goto cleanup;
          _lv=(long)_vt->val.number;
          pool[i-1]=ma(SO(long));
          memcpy(pool[i-1],&_lv,SO(long));
          v=pool[i-1];
          fc++;}BR;
        CS 'f':{float _fv;
          Vt*_vt=xad[i-1];
          if(_vt->tag!=NUM)goto cleanup;
          _fv=(float)_vt->val.number;
          pool[i-1]=ma(SO(float));
          memcpy(pool[i-1],&_fv,SO(float));
          v=pool[i-1];
          fc++;}BR;
        CS 'd':{D _dv;
          Vt*_vt=xad[i-1];
          if(_vt->tag!=NUM)goto cleanup;
          _dv=(D)_vt->val.number;
          pool[i-1]=ma(SO(D));
          memcpy(pool[i-1],&_dv,SO(D));
          v=pool[i-1];
          fc++;}BR;
        CS 'c':{UC _cv;
          Vt*_vt=xad[i-1];
          if(_vt->tag!=CHAR)goto cleanup;
          _cv=(UC)_vt->val._char;
          pool[i-1]=ma(SO(UC));
          memcpy(pool[i-1],&_cv,SO(UC));
          v=pool[i-1];
          fc++;}BR;}
      args[i-1]=t;
      values[i-1]=v;}}
  P dlh=dlopen(lib,RTLD_LAZY);
  if(!dlh)goto cleanup;
  P exfn=dlsym(dlh,fun);
  S e=dlerror();
  if(!exfn||e)goto cleanup;
  if(ffi_prep_cif(&cif,FFI_DEFAULT_ABI,argc,ret,args)!=FFI_OK)goto cleanup;
  if(retvsz)retv=ma(retvsz);
  ffi_call(&cif,exfn,retv,values);
  dlclose(dlh);
  Vt*rv=st->nil;
  SW(rett){CS 'v':BR;
    CS '$':{S s=*(S*)retv;
      Z z=strlen(s);
      Ar*l=Ank(z);
      for(Z i=0;i<z;i++)l->data[i]=CHARS[s[i]];
      rv=Vna(l);}BR;
    CS '@':{S s=*(S*)retv;
      Z z=strlen(s);
      Ar*l=Ank(z);
      for(Z i=0;i<z;i++)l->data[i]=CHARS[s[i]];
      rv=Vna(l);
      free(s);}BR;
    CS 'p':rv=Vnn((Z)*(P*)retv);BR;
    CS 'i':rv=Vnn(*(int*)retv);BR;
    CS 'l':rv=Vnn(*(long*)retv);BR;
    CS 'f':rv=Vnn(*(float*)retv);BR;
    CS 'd':rv=Vnn(*(D*)retv);BR;
    CS 'c':rv=Vnc(*(UC*)retv);BR;}
  FR(retv);
  for(Z i=0;i<fc;i++)FR(pool[i]);R rv;
cleanup:for(Z i=0;i<fc;i++)FR(pool[i]);R st->udf;}
Vt*vexplode(St*st,vt*self,Vt*x,Vt*y){S del=Vshow(x);
  S s=Vstr(y);
  Z dell=strlen(del);
  Z sl=strlen(s);
  Ar*r=An();
  Ar*t=An();
  for(Z i=0;i<sl;i++){if(strncmp(&s[i],del,dell)==0){Ap(r,Vna(t));
      t=An();
      i+=dell-1;CN;}
    Ap(t,CHARS[s[i]]);}
  FR(s);
  FR(del);
  Ap(r,Vna(t));R Vna(r);}
Vt*vimplode(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||!yad)R y;
  S del=Vshow(x);
  Ar*r=An();
  for(Z i=0;i<yal;i++){S s=Vshow(yad[i]);
    S _s=s;
    WH(*_s)Ap(r,CHARS[*_s++]);
    FR(s);
    if(i!=yal-1){S s=del;
      WH(*s)Ap(r,CHARS[*s++]);}}
  FR(del);R Vna(r);}
Vt*vtackleft(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*r=Ank(yal+1);
  r->data[0]=x;
  for(Z i=0;i<yal;i++)r->data[i+1]=yad[i];R Vna(r);}
Vt*vtackright(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*r=Ank(yal+1);
  for(Z i=0;i<yal;i++)r->data[i]=yad[i];
  r->data[yal]=x;R Vna(r);}
Vt*veye(St*st,vt*self,Vt*x){if(xt==NUM&&!spnp(xn)){Z k=fabs(xn);
    Ar*r=Ank(k);
    for(Z i=0;i<k;i++){Ar*rw=Ank(k);
      for(Z j=0;j<k;j++)rw->data[j]=NUMS[i==j];
      r->data[i]=Vna(rw);}
    R Vna(r);}
  R st->udf;}
Vt*vinfix(St*st,vt*self,Vt*x){R vbehead(st,N,vprefixes(st,N,x));}
Vt*vvalue(St*st,vt*self,Vt*x){S s=Vstr(x);
  Vt*r=Tget(st->env,s);
  FR(s);R r?r:st->udf;}
Vt*vudf1(St*st,vt*self,Vt*x){R st->udf;}
Vt*vudf2(St*st,vt*self,Vt*x,Vt*y){R st->udf;}
#define X UINT_MAX
#define DEFVERB(__symb,__rm,__rl,__rr,__m,__d){__symb,{__rm,__rl,__rr},N,F,F,v##__m,v##__d}
#define DEFVERBD(__symb,__rm,__rl,__rr,__m,__d){__symb ".",{__rm,__rl,__rr},N,F,F,v##__m,v##__d}
#define DEFVERBC(__symb,__rm,__rl,__rr,__m,__d){__symb ":",{__rm,__rl,__rr},N,F,F,v##__m,v##__d}
vt VERBS[]={DEFVERB(":",0,0,0,const,bind),DEFVERBC(":",X,0,0,unbind,obverse),DEFVERB("+",0,X,X,flip,plus),DEFVERBD("+",X,X,X,fibonacci,gcd),DEFVERBC("+",X,X,X,sin,combine),DEFVERB("-",X,X,X,negate,minus),DEFVERBD("-",X,X,X,atan,atan2),DEFVERB("*",0,X,X,first,times),DEFVERBD("*",X,X,X,factorial,lcm),DEFVERBC("*",X,X,0,double,replicate),DEFVERB("%",X,X,X,reciprocal,divide),DEFVERBD("%",X,X,X,sqrt,root),DEFVERBC("%",X,X,X,halve,idivide),DEFVERB("!",X,X,X,enum,mod),DEFVERBD("!",X,X,X,iota,range),DEFVERBC("!",0,X,0,odometer,chunks),DEFVERB("^",X,X,X,exp,power),DEFVERBD("^",X,X,X,nlog,log),DEFVERB("=",0,X,X,permute,equals),DEFVERBD("=",0,0,0,occurences,mask),DEFVERBC("=",0,0,0,classify,equals),DEFVERB("~",X,X,X,not,not_equals),DEFVERBD("~",X,0,0,sign,insert),DEFVERBC("~",0,0,0,not,not_equals),DEFVERB("<",X,X,X,pred,less),DEFVERBD("<",X,X,X,floor,lesseq),DEFVERBC("<",0,X,0,gradedown,nudge_left),DEFVERB(">",X,X,X,succ,greater),DEFVERBD(">",X,X,X,ceil,greatereq),DEFVERBC(">",0,X,0,gradeup,nudge_right),DEFVERB(",",0,0,0,enlist,join),DEFVERBD(",",X,0,0,enlist,enpair),DEFVERB("#",0,X,0,count,take),DEFVERBD("#",0,0,0,where,copy),DEFVERBC("#",0,0,0,group,buckets),DEFVERB("_",0,X,0,nub,drop),DEFVERBD("_",0,X,0,unbits,unbase),DEFVERBC("_",X,X,X,bits,base),DEFVERB("?",0,0,0,unique,find),DEFVERB("&",0,X,X,flatten,minand),DEFVERB("|",0,X,X,reverse,maxor),DEFVERBD("|",X,X,0,round,rotate),DEFVERBC("|",0,X,0,depth,windows),DEFVERB("@",X,0,X,abs,at),DEFVERBD("@",0,0,0,shuffle,member),DEFVERBC("@",0,0,0,infix,indexof),DEFVERB("{",0,0,0,head,bin),DEFVERBD("{",0,0,0,tail,cut),DEFVERBC("{",0,X,X,prefixes,shl),DEFVERB("}",0,X,X,behead,xor),DEFVERBD("}",0,0,0,curtail,band),DEFVERBC("}",0,X,X,suffixes,shr),DEFVERB("[",X,0,0,factors,left),DEFVERBD("[",X,X,X,bnot,bor),DEFVERBC("[",X,X,0,primes,parts),DEFVERB("]",0,0,0,same,right),DEFVERBD("]",0,X,X,sort,outof),DEFVERBC("]",0,0,0,unsort,explode),DEFVERBD("`",0,0,0,symbol,apply1),DEFVERBC("`",0,0,0,square,apply2),DEFVERB("$",0,0,0,shape,reshape),DEFVERBD("$",0,0,0,repr,format),DEFVERBC("$",X,0,0,eye,implode),DEFVERBD("p",0,0,0,print,udf2),DEFVERBD("P",0,0,0,println,udf2),DEFVERBD("c",X,0,0,putch,udf2),DEFVERBD("s",0,0,0,selfref1,selfref2),DEFVERBD("F",0,0,0,read,write),DEFVERBD("r",0,X,X,deal,roll),DEFVERBD("t",0,0,0,type,cast),DEFVERBD("E",0,0,0,exit,udf2),DEFVERBD("y",0,0,0,system,system2),DEFVERBD("e",0,0,0,eval,udf2),DEFVERBD("i",0,0,0,import,foreign),DEFVERBD("L",0,0,0,udf1,tackleft),DEFVERBD("R",0,0,0,udf1,tackright),DEFVERBD("v",0,0,0,value,udf2)};
Vt*_advfold_m(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R x;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*t=xad[0];
  Ar*tx=xa;
  for(Z i=1;i<tx->length;i++)t=tgth(st,v,t,tx->data[i],0,0,v->rank[1],v->rank[2]);R t;}
Vt*_advfold_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(!yad)R x;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*t=x;
  Ar*ty=ya;
  for(Z i=0;i<ty->length;i++)t=tgth(st,v,t,ty->data[i],0,0,v->rank[1],v->rank[2]);R t;}
Vt*_advscan_m(St*st,vt*self,Vt*x){if(xt!=ARRAY||!xad)R x;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Ar*r=An();
  Vt*t=xad[0];
  Ar*tx=xa;
  Ap(r,t);
  for(Z i=1;i<tx->length;i++){t=tgth(st,v,t,tx->data[i],0,0,v->rank[1],v->rank[2]);
    Ap(r,t);}
  R Vna(r);}
Vt*_advscan_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||!yad)R y;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Ar*r=An();
  Vt*t=x;
  Ar*ty=ya;
  Ap(r,t);
  for(Z i=1;i<ty->length;i++){t=tgth(st,v,t,ty->data[i],0,0,v->rank[1],v->rank[2]);
    Ap(r,t);}
  R Vna(r);}
Vt*_adveach_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  if(xt!=ARRAY)R eR(st,v,x,0,1);
  if(!xad)R x;R eR(st,v,x,0,1);}
Vt*_adveach_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  if(xt!=ARRAY)x=venlist(st,N,x);
  if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*r=An();
  Ar*tx=xa;
  Ar*ty=ya;
  for(Z i=0;i<tx->length&&i<ty->length;i++)Ap(r,tgth(st,v,tx->data[i],ty->data[i],0,0,v->rank[1],v->rank[2]));R Vna(r);}
Vt*_advconverge_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*t;
  LOOP{t=x;
    x=eR(st,v,x,0,v->rank[0]);
    if(Veq(x,t))BR;}
  R x;}
vt*cnjbond(St*st,Vt*x,Vt*y);
Vt*_advconverge_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  if(yt!=ARRAY)R tgth(st,v,y,x,0,0,v->rank[1],v->rank[2]);
  if(!yad)R x;
  v=cnjbond(st,Vnv(v),x);R eR(st,v,y,0,1);}
Vt*_advconverges_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  Ar*r=An();
  Vt*t;
  Ap(r,x);
  LOOP{t=x;
    x=apM(st,_v,x);
    if(Veq(x,t))BR;
    Ap(r,x);}
  R Vna(r);}
Vt*_advconverges_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  if(yt!=ARRAY)R tgth(st,v,y,x,0,0,v->rank[1],v->rank[2]);
  if(!yad)R x;
  v=cnjbond(st,x,Vnv(v));R eR(st,v,y,0,1);}
Vt*_adveachprior_m(St*st,vt*self,Vt*x){if(xt!=ARRAY||xal<2)R x;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Ar*r=An();
  for(Z i=1;i<xal;i++)Ap(r,tgth(st,v,xad[i],xad[i-1],0,0,v->rank[1],v->rank[2]));R Vna(r);}
Vt*_adveachprior_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||!yad)R y;
  Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Ar*r=An();
  for(Z i=0;i<yal;i++)Ap(r,tgth(st,v,yad[i],i==0?x:yad[i-1],0,0,v->rank[1],v->rank[2]));R Vna(r);}
Vt*_advreflex_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;R tgth(st,v,x,x,0,0,v->rank[1],v->rank[2]);}
Vt*_advreflex_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;R tgth(st,v,y,x,0,0,v->rank[1],v->rank[2]);}
Vt*_advamend_m(St*st,vt*self,Vt*x){R st->udf;}
Vt*_advamend_d(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  Vt*v=self->bonds->data[0];
  if(v->tag!=ARRAY)v=venlist(st,N,v);
  if(yt!=ARRAY)y=venlist(st,N,y);
  Ar*r=Ac(ya);
  Z l=xal;
  Ar*t=v->val.array;
  for(Z i=0;i<t->length;i++){Vt*n=t->data[i];
    if(n->tag!=NUM)BR;
    As(r,n->val.number,Ai(xa,i<l?i:l-1));}
  R Vna(r);}
Vt*_advfilter_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  vt*v=_v->val.verb;
  Ar*r=An();
  for(Z i=0;i<xal;i++){Vt*b=eR(st,v,xad[i],0,v->rank[0]);
    if(VTp(b))Ap(r,xad[i]);}
  R Vna(r);}
Vt*_advfilter_d(St*st,vt*self,Vt*x,Vt*y){R st->udf;}
Vt*_advspan_m(St*st,vt*self,Vt*x){Vt*v=self->bonds->data[0];
  if(v->tag!=VERB)R st->udf;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(!xad)R x;
  Ar*r=An();
  Ar*p=An();
  for(Z i=0;i<xal;i++){Vt*b=apM(st,v,xad[i]);
    if(VTp(b)){Ap(r,Vna(p));
      p=An();}else Ap(p,xad[i]);}
  Ap(r,Vna(p));R Vna(r);}
Vt*_advspan_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*r=vwindows(st,N,x,y);R eR(st,v,r,0,1);}
Vt*_advinverse_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  vt*iv=Tget(Inverses,v->name);
  if(!iv)R st->udf;R eR(st,iv,x,0,iv->rank[0]);}
Vt*_advinverse_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->data[0];
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  vt*iv=Tget(Inverses,v->name);
  if(!iv)R st->udf;
  Vt*a=eR(st,iv,x,0,iv->rank[0]);
  Vt*b=eR(st,iv,y,0,iv->rank[0]);R apD(st,_v,a,b);}
#define ADVERB(__name,__symb)\
  vt*adv##__name(St*st,Vt*v){\
    vt*nv=vnew();\
    nv->bonds=Ank(1);\
    nv->bonds->data[0]=v;\
    S r=Vshow(v);\
    Z l=strlen(r)+strlen(__symb)+1;\
    nv->name=ma(l);\
    snprintf(nv->name,l,"%s" __symb,r);\
    FR(r);\
    nv->rank[0]=0;\
    nv->monad=_adv##__name##_m;\
    nv->dyad=_adv##__name##_d;\
    R nv;}
ADVERB(fold,"/");
ADVERB(converge,"/.");
ADVERB(scan,"\\");
ADVERB(converges,"\\.");
ADVERB(each,"\"");
ADVERB(eachprior,"\".");
ADVERB(reflex,";.");
ADVERB(amend,"`");
ADVERB(filter,"&.");
ADVERB(span,"/:");
ADVERB(inverse,"-:");
advt ADVERBS[]={{"/",advfold,N},  {"/.",advconverge,N},{"\\",advscan,N}, {"\\.",advconverges,N},{"\"",adveach,N}, {"\".",adveachprior,N},{";.",advreflex,N},{"`",advamend,N},{"&.",advfilter,N},{"/:",advspan,N},{"-:",advinverse,N}};
Vt*_cnjbond_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag==VERB&&v2->tag==VERB)R apM(st,v1,apM(st,v2,x));
  elif(v1->tag==VERB)R apD(st,v1,x,v2);
  elif(v2->tag==VERB)R apD(st,v2,v1,x);
  else R st->udf;}
Vt*_cnjbond_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag==VERB&&v2->tag==VERB)R apM(st,v1,apD(st,v2,x,y));
  elif(v1->tag==VERB)R apD(st,v1,apD(st,v1,x,y),v2);
  elif(v2->tag==VERB)R apD(st,v2,v1,apD(st,v2,x,y));
  else R st->udf;}
Vt*_cnjpick_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=ARRAY)R st->udf;
  Vt*n=apM(st,v1,x);
  Vt*f=vat(st,N,v2,n);R apM(st,f,x);}
Vt*_cnjpick_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=ARRAY)R st->udf;
  Vt*n=apD(st,v1,x,y);
  Vt*f=vat(st,N,v2,n);R apD(st,f,x,y);}
Vt*_cnjwhile_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag==VERB){LOOP{if(!VTp(apM(st,v1,x)))BR;
      x=apM(st,v2,x);}}elif(v1->tag==NUM){Z k=(Z)fabs(v1->val.number);
    for(Z i=0;i<k;i++)x=apM(st,v2,x);}
  R x;}
Vt*_cnjwhile_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag==VERB){LOOP{if(!VTp(apD(st,v1,x,y)))BR;
      x=apD(st,v2,x,y);}}elif(v1->tag==NUM){Z k=(Z)fabs(v1->val.number);
    for(Z i=0;i<k;i++)x=apD(st,v2,x,y);}
  R x;}
Vt*_cnjrank_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=NUM)R st->udf;
  UI rank=
      v2->val.number==INFINITY?UINT_MAX:fabs(v2->val.number);R eR(st,v1->val.verb,x,0,rank);}
Vt*_cnjrank_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB)R st->udf;
  UI rl;
  UI rr;
  if(v2->tag==NUM)rl=rr=v2->val.number==INFINITY?UINT_MAX:fabs(v2->val.number);
  elif(v2->tag==ARRAY&&v2->val.array->length==2){Vt*a=v2->val.array->data[0];
    Vt*b=v2->val.array->data[1];
    if(a->tag!=NUM)R st->udf;
    rl=a->val.number==INFINITY?UINT_MAX:fabs(a->val.number);
    if(b->tag!=NUM)R st->udf;
    rr=b->val.number==INFINITY?UINT_MAX:fabs(b->val.number);}
  else R st->udf;R tgth(st,v1->val.verb,x,y,0,0,rl,rr);}
Vt*_cnjmonaddyad_m(St*st,vt*self,Vt*x){Vt*v=self->bonds->data[0];
  if(v->tag!=VERB)R st->udf;R eR(st,v->val.verb,x,0,v->val.verb->rank[0]);}
Vt*_cnjmonaddyad_d(St*st,vt*self,Vt*x,Vt*y){Vt*v=self->bonds->data[1];
  if(v->tag!=VERB)R st->udf;R tgth(st,v->val.verb,x,y,0,0,v->val.verb->rank[1],v->val.verb->rank[2]);}
Vt*_cnjif_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=VERB)R st->udf;
  Vt*b=apM(st,v2,x);
  if(VTp(b))R x;R apM(st,v1,x);}
Vt*_cnjif_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=VERB)R st->udf;
  Vt*b=apD(st,v2,x,y);
  if(VTp(b))R y;R apD(st,v1,x,y);}
Vt*_cnjunder_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=VERB)R st->udf;
  vt*iv=Tget(Inverses,v2->val.verb->name);
  if(!iv)R st->udf;
  Vt*v=apM(st,v2,x);
  v=apM(st,v1,v);R eR(st,iv,v,0,iv->rank[0]);}
Vt*_cnjunder_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->data[0];
  Vt*v2=self->bonds->data[1];
  if(v1->tag!=VERB||v2->tag!=VERB)R st->udf;
  vt*iv=Tget(Inverses,v2->val.verb->name);
  if(!iv)R st->udf;
  Vt*a=apM(st,v2,x);
  Vt*b=apM(st,v2,y);
  Vt*v=apD(st,v1,a,b);R eR(st,iv,v,0,iv->rank[0]);}
#define CONJUNCTION(__name,__symb)\
  vt*cnj##__name(St*st,Vt*x,Vt*y){\
    vt*nv=vnew();\
    nv->bonds=Ank(2);\
    nv->bonds->data[0]=x;\
    nv->bonds->data[1]=y;\
    S rx=Vshow(x);\
    S ry=Vshow(y);\
    Z l=strlen(rx)+strlen(ry)+strlen(__symb)+1;\
    nv->name=ma(l);\
    snprintf(nv->name,l,"%s"__symb"%s",rx,ry);\
    FR(rx);\
    FR(ry);\
    nv->rank[0]=0;\
    nv->rank[1]=0;\
    nv->rank[1]=0;\
    nv->monad=_cnj##__name##_m;\
    nv->dyad=_cnj##__name##_d;\
    R nv;}
CONJUNCTION(bond,";");
CONJUNCTION(pick,"?.");
CONJUNCTION(while,"?:");
CONJUNCTION(rank,"\":");
CONJUNCTION(monaddyad,";:");
CONJUNCTION(if,"&:");
CONJUNCTION(under,"^:");
advt CONJUNCTIONS[]={{";",N,cnjbond},{"?.",N,cnjpick},{"?:",N,cnjwhile},{"\":",N,cnjrank},{";:",N,cnjmonaddyad},{"&:",N,cnjif},{"^:",N,cnjunder}};
#define FINDER(kind,rname,table)\
  kind*G##rname(S s){\
    for(Z i=0;i<AE(table);i++){\
      if(strcmp(table[i].name,s)==0)\
        R &table[i];}\
    R N;}
FINDER(vt,v,VERBS);
FINDER(advt,adv,ADVERBS);
FINDER(advt,cnj,CONJUNCTIONS);
Nt*Nn(enum Ntag_t tag){Nt*node=ma(SO(Nt));
  node->tag=tag;R node;}
Nt*Nns(Ar*l){Nt*node=ma(SO(Nt));
  node->tag=N_STRAND;
  node->l=l;R node;}
Nt*Nnl(Vt*v){Nt*node=ma(SO(Nt));
  node->tag=N_LITERAL;
  node->v=v;R node;}
Nt*Nn1(enum Ntag_t tag,Nt*a){Nt*node=ma(SO(Nt));
  node->tag=tag;
  node->a=a;R node;}
Nt*Nn2(enum Ntag_t tag,Nt*a,Nt*b){Nt*node=ma(SO(Nt));
  node->tag=tag;
  node->a=a;
  node->b=b;R node;}
Nt*Nn3(enum Ntag_t tag,Nt*a,Nt*b,Nt*c){Nt*node=ma(SO(Nt));
  node->tag=tag;
  node->a=a;
  node->b=b;
  node->c=c;R node;}
typedef struct{Lt*lexer;
  St*st;
  Z pos;
  Z end;
  Z dp;
  B bn;}Pt;
Pt*Pnew(St*state){Pt*parser=ma(SO(Pt));
  parser->st=state;R parser;}
V Perror(Pt*parser,S s){fatal(s);}
B Pdone(Pt*parser){R parser->pos>=parser->end;}
Tkt*Plook(Pt*parser,Z offset){Z pos=parser->pos+offset;
  if(pos>=parser->end)R N;R Ai(parser->lexer->tokens,pos);}
B Pstop(Pt*parser){Tkt*tok=Plook(parser,0);
  if(!tok)R T;R tok->tag==T_RPAR;}
V Peat(Pt*parser){if(!Pdone(parser))parser->pos++;}
Nt*PPexpr(Pt*parser);
Nt*PPverb(Pt*parser){Tkt*tok=Plook(parser,0);
  if(!tok||tok->tag!=T_PUNCT)R N;
  vt*verb=Gv(tok->text);
  if(!verb)R N;R Nnl(Vnv(verb));}
Vt*_advwrapper_m(St*st,vt*self,Vt*x){advt*av=self->bonds->data[0];
  if(xt!=VERB)R st->udf;R Vnv(av->adverb(st,x));}
Vt*_advwrapper_d(St*st,vt*self,Vt*x,Vt*y){advt*av=self->bonds->data[0];
  if(xt!=VERB)R st->udf;
  vt*v=av->adverb(st,x);R eR(st,v,y,0,v->rank[0]);}
Nt*PPadvatom(Pt*parser){Tkt*tok=Plook(parser,0);
  if(!tok||tok->tag!=T_PUNCT)R N;
  advt*adverb=Gadv(tok->text);
  if(!adverb)R N;
  vt*nv=vnew();
  nv->name=sdup(tok->text);
  nv->bonds=Ank(1);
  nv->bonds->data[0]=adverb;
  nv->rank[0]=0;
  nv->rank[1]=0;
  nv->rank[2]=0;
  nv->monad=_advwrapper_m;
  nv->dyad=_advwrapper_d;R Nnl(Vnv(nv));}
Vt*_cnjwrapper_d(St*st,vt*self,Vt*x,Vt*y){advt*av=self->bonds->data[0];R Vnv(av->conjunction(st,x,y));}
Nt*PPcnjatom(Pt*parser){Tkt*tok=Plook(parser,0);
  if(!tok||tok->tag!=T_PUNCT)R N;
  advt*adverb=Gcnj(tok->text);
  if(!adverb)R N;
  vt*nv=vnew();
  nv->name=sdup(tok->text);
  nv->bonds=Ank(1);
  nv->bonds->data[0]=adverb;
  nv->rank[0]=0;
  nv->rank[1]=0;
  nv->rank[2]=0;
  nv->monad=N;
  nv->dyad=_cnjwrapper_d;R Nnl(Vnv(nv));}
Nt*PPatom(Pt*parser){Tkt*tok=Plook(parser,0);
  Nt*node=N;
  SW(tok->tag){CS T_RPAR:Perror(parser,"unmatched");
  CS T_LPAR:Peat(parser);
    tok=Plook(parser,0);
    if(tok&&tok->tag==T_RPAR){node=Nnl(parser->st->unit);BR;}
    parser->dp++;
    node=PPexpr(parser);
    if(parser->bn)node->dp=2;
    else node->dp=parser->dp;
    parser->dp--;
    tok=Plook(parser,0);
    if(!tok||tok->tag!=T_RPAR)Perror(parser,"unmatched");BR;
  CS T_PUNCT:node=PPverb(parser);
    if(!node)node=PPadvatom(parser);
    if(!node)node=PPcnjatom(parser);
    if(!node)Perror(parser,"parse");BR;
  CS T_NUM:node=Nnl(Vnn(strtod(tok->text,N)));BR;
  CS T_BNUM:{if(!tok->text[1])Perror(parser,"trailing-base");
    I base=tok->text[0]=='x'?16:tok->text[0]=='b'?2:8;
    node=Nnl(Vnn(strtol(tok->text+1,N,base)));}BR;
  CS T_NAME:node=Nnl(Vny(sdup(tok->text)));BR;
  CS T_QUOTE:if(!*tok->text)node=Nnl(parser->st->unit);
    elif(!*(tok->text+1))node=Nnl(Vnc(tok->text[0]));
    else{Z z=strlen(tok->text);
      Ar*r=Ank(z);
      for(Z i=0;i<z;i++)r->data[i]=CHARS[tok->text[i]];
      node=Nnl(Vna(r));}BR;}
  if(!node)Perror(parser,"parse");
  Peat(parser);R node;}
B isunb(St*st,S s){if(st->args->data){Ar*args=Ai(st->args,-1);
    Z argc=args->length-1;
    if(argc==2&&strcmp(s,"y")==0)R F;
    elif(strcmp(s,"x")==0)R F;}
  elif(Thas(st->env,s))R F;R T;}
Nt*PPa(Pt*parser,Nt*a,enum Tkt tag){Tkt*tok;
  if((tok=Plook(parser,0))&&(tok->tag==tag||(tag==T_NUM&&tok->tag==T_BNUM))){if(tag==T_NAME&&!isunb(parser->st,tok->text))R N;
    Ar*as=An();
    Ap(as,a->v);
    do{if(tag==T_NAME&&tok->tag==T_NAME&&!isunb(parser->st,tok->text))BR;
      a=PPatom(parser);
      Ap(as,a->v);}WH((tok=Plook(parser,0))&&(tok->tag==tag||(tag==T_NUM&&tok->tag==T_BNUM)));R Nnl(Vna(as));}
  R N;}
Nt*_PPnoun(Pt*parser){Nt*n;
  Nt*a=PPatom(parser);
  if(a->tag==N_LITERAL&&a->v->tag==NUM&&(n=PPa(parser,a,T_NUM)))R n;
  elif(a->tag==N_LITERAL&&a->v->tag==SYM&&isunb(parser->st,a->v->val.symbol)&&(n=PPa(parser,a,T_NAME)))R n;
  elif(a->tag==N_LITERAL&&((a->v->tag==ARRAY&&Cap(a->v->val.array))||a->v->tag==CHAR)&&(n=PPa(parser,a,T_QUOTE)))R n;R a;}
Nt*PPnoun(Pt*parser,B flat){Nt*a=flat?PPatom(parser):_PPnoun(parser);
  Tkt*tok;
  if((tok=Plook(parser,0))&&tok->tag==T_PUNCT&&strcmp(tok->text,",:")==0){Peat(parser);
    Ar*l=An();
    Ap(l,a);
    LOOP{if(Pstop(parser))Perror(parser,"trailing-strand");
      a=flat?PPatom(parser):_PPnoun(parser);
      Ap(l,a);
      if(!((tok=Plook(parser,0))&&tok->tag==T_PUNCT&&strcmp(tok->text,",:")==0))BR;
      Peat(parser);}
    R Nns(l);}
  R a;}
B Nisv(Pt*parser,Nt*n){Vt*v;
  if(n->tag==N_FUN)R T;
  elif(n->tag==N_ADV||n->tag==N_CONJ||n->tag==N_PARTIAL_CONJ)R T;
  elif(n->tag==N_FORK||n->tag==N_HOOK||n->tag==N_BOND||n->tag==N_OVER)R T;
  elif(n->tag==N_LITERAL&&n->v->tag==VERB)R T;
  elif(n->tag==N_LITERAL&&n->v->tag==SYM&&(v=Tget(parser->st->env,n->v->val.symbol))&&v->tag==VERB)R T;R F;}
Nt*PPadv(Pt*parser,Nt*v,bool*flag){Tkt*tok;
  advt*adv;
  Nt*t;
  LOOP{tok=Plook(parser,0);
    if(!tok||tok->tag!=T_PUNCT)BR;
    if((adv=Gadv(tok->text))){if(flag)*flag=T;
      Peat(parser);
      t=Nn(N_ADV);
      t->av=adv;
      t->a=v;
      v=t;}else BR;}
  R v;}
Nt*PPcnj(Pt*parser,Nt*v,bool*flag){Tkt*tok;
  advt*adv;
  Nt*t;
  LOOP{tok=Plook(parser,0);
    if(!tok||tok->tag!=T_PUNCT)BR;
    if((adv=Gcnj(tok->text))){if(flag)*flag=T;
      Peat(parser);
      if(Pstop(parser)){t=Nn(N_PARTIAL_CONJ);
        t->av=adv;
        t->a=v;}else{t=Nn(N_CONJ);
        t->av=adv;
        t->a=v;
        t->b=PPnoun(parser,T);}
      v=t;}else BR;}
  R v;}
B is_apply(Nt*n){R n->tag==N_LITERAL&&n->v->tag==VERB&&(strcmp(n->v->val.verb->name,"`.")==0||strcmp(n->v->val.verb->name,"`:")==0);}
B is_obverse(Nt*n){R n->tag==N_LITERAL&&n->v->tag==VERB&&strcmp(n->v->val.verb->name,"::")==0;}
Nt*PPexpr(Pt*parser){Tkt*tmp;
  Ar*ns=An();
  WH(!Pstop(parser)){if(!ns->data&&(tmp=Plook(parser,0))&&tmp->tag==T_PUNCT&&strcmp(tmp->text,":")==0){Peat(parser);
      Nt*r=PPexpr(parser);
      if(!r)r=Nnl(parser->st->nil);R Nn1(N_FUN,r);}
    Nt*n=PPnoun(parser,F);
    if(!ns->data&&n->tag==N_LITERAL&&n->v->tag==SYM&&(tmp=Plook(parser,0))&&tmp->tag==T_PUNCT&&strcmp(tmp->text,":")==0){Peat(parser);
      B t=parser->bn;
      parser->bn=T;
      Nt*r=PPexpr(parser);
      parser->bn=t;R Nn2(N_BIND,n,r);}
    LOOP{B flag=F;
      n=PPadv(parser,n,&flag);
      n=PPcnj(parser,n,&flag);
      if(!flag)BR;}
    Ap(ns,n);}
  Z len;
  Nt*l,*m,*r;
  LOOP{len=ns->length;
    if(len<2)BR;
    if(len>=3&&(is_apply(Ai(ns,-2))||is_obverse(Ai(ns,-2)))&&Nisv(parser,Ai(ns,-1))){r=AP(ns);
      m=AP(ns);
      l=AP(ns);
      Ap(ns,Nn3(N_DYAD,m,l,r));}elif(len>=3&&!Nisv(parser,Ai(ns,-1))&&Nisv(parser,Ai(ns,-2))&&!Nisv(parser,Ai(ns,-3))){r=AP(ns);
      m=AP(ns);
      l=AP(ns);
      Ap(ns,Nn3(N_DYAD,m,l,r));}elif(len>=3&&Nisv(parser,Ai(ns,-1))&&Nisv(parser,Ai(ns,-2))&&Nisv(parser,Ai(ns,-3))){r=AP(ns);
      m=AP(ns);
      l=AP(ns);
      Ap(ns,Nn3(N_FORK,l,m,r));}elif(len>=3&&Nisv(parser,Ai(ns,-1))&&Nisv(parser,Ai(ns,-2))&&!Nisv(parser,Ai(ns,-3))){r=AP(ns);
      m=AP(ns);
      l=AP(ns);
      Ap(ns,Nn3(N_OVER,l,m,r));}elif(len>=2&&is_apply(Ai(ns,-1))){r=AP(ns);
      l=AP(ns);
      Ap(ns,Nn2(N_BOND,r,l));}elif(len>=2&&!Nisv(parser,Ai(ns,-1))&&Nisv(parser,Ai(ns,-2))){r=AP(ns);
      l=AP(ns);
      Ap(ns,Nn2(N_MONAD,l,r));}elif(len>=2&&Nisv(parser,Ai(ns,-1))&&Nisv(parser,Ai(ns,-2))){r=AP(ns);
      l=AP(ns);
      Ap(ns,Nn2(N_HOOK,l,r));}elif(len>=2&&Nisv(parser,Ai(ns,-1))&&!Nisv(parser,Ai(ns,-2))){r=AP(ns);
      l=AP(ns);
      Ap(ns,Nn2(N_BOND,r,l));}elif(len>=3){r=AP(ns);
      m=AP(ns);
      l=AP(ns);
      Ap(ns,Nn3(N_INDEX2,m,l,r));}elif(len>=2){r=AP(ns);
      l=AP(ns);
      Ap(ns,Nn2(N_INDEX1,l,r));}}
  R ns->data?ns->data[0]:N;}
Nt*Pparse(Pt*parser,Lt*lexer){parser->lexer=lexer;
  parser->pos=0;
  parser->end=parser->lexer->tokens->length;
  Nt*node=PPexpr(parser);
  if(!Pdone(parser)){Tkt*tok=Plook(parser,0);
    if(tok&&tok->tag==T_RPAR)Perror(parser,"unmatched");
    Perror(parser,"parse");}
  R node;}
Vt*Srun(St*st,S program){Lt*lexer=Lnew();
  Llex(lexer,program);
  Pt*parser=Pnew(st);
  Nt*node=Pparse(parser,lexer);
  Ar*t=lexer->tokens;
  for(Z i=0;i<t->length;i++){Tkt*tok=t->data[i];
    if(tok->text)FR(tok->text);
    FR(tok);}
  FR(t->data);
  FR(t);
  Vt*r=Swalk(st,node);
  FR(parser);R r;}
cS VHELP =\
":  monadic const         create a function that always yields x" "\n"\
":  dyadic  bind          bind y to symbol x" "\n"\
":: monadic unbind        unbind symbol x" "\n"\
":: dyadic  obverse       insert inverse for x" "\n"\
"+  monadic flip          transpose matrix" "\n"\
"+  dyadic  plus          add numbers" "\n"\
"+. monadic fibonacci     compute xth fibonacci number" "\n"\
"+. dyadic  gcd           compute gcd(x, y)" "\n"\
"+: monadic sin           compute sin(x)" "\n"\
"+: dyadic  combine       combine digits of x and y, same as 10_.(10_:),(10_:)" "\n"\
"-  monadic negate        negate number" "\n"\
"-  dyadic  minus         subtract numbers" "\n"\
"*  monadic first         yield first element of x" "\n"\
"*  dyadic  times         multiply numbers" "\n"\
"*. monadic factorial     x!" "\n"\
"*. dyadic  lcm           compute lcm(x, y)" "\n"\
"*: monadic double        x * 2" "\n"\
"*: dyadic  replicate     repeat y x times" "\n"\
"%  monadic reciprocal    1 / x" "\n"\
"%  dyadic  divide        divide numbers" "\n"\
"%. monadic sqrt          compute square root of x" "\n"\
"%. dyadic  root          compute xth root of y" "\n"\
"%: monadic halve         x % 2" "\n"\
"%: dyadic  idivide       same as % divide, but result is always integer" "\n"\
"!  monadic enum          [0, x)" "\n"\
"!  dyadic  mod           modulo of numbers" "\n"\
"!. monadic iota          [1, x]" "\n"\
"!. dyadic  range         [x, y] (also works for chars and even if x > y)" "\n"\
"!: monadic odometer      !:10 10 is 0 0,:0 1,: ... 1 0,:1 1,: ... 9 8,:9 9" "\n"\
"!: dyadic  chunks        split y into x-sized chunks" "\n"\
"^  monadic exp           e^x" "\n"\
"^  dyadic  power         raise number to a power" "\n"\
"^. monadic nlog          ln(x)" "\n"\
"^. dyadic  log           log(y)/log(x)" "\n"\
"=  monadic permute       generate permutations of x" "\n"\
"=  dyadic  equals        test whether x and y are equal" "\n"\
"=. monadic occurences    count occurences of elts, =.'Hello World!' is 0 0 0 1 0 0 0 1 0 2 0 0" "\n"\
"=. dyadic  mask          mask one array in another, 'abxyzabayxxyabxyk'=.'xy' is 0 0 1 1 0 0 0 0 0 0 2 2 0 0 3 3 0" "\n"\
"=: monadic classify      assign unique index to each unique elt, =:'Hello World!' is 0 1 2 2 3 4 5 3 6 2 7 8" "\n"\
"=: dyadic  match         same as = equals, but rank 0, so compares x and y as whole" "\n"\
"~  monadic not           logical not, nil udf () 0 4t.0 are not truthy, everything else is truthy" "\n"\
"~  dyadic  notequals     test whether x and y are not equal" "\n"\
"~. monadic sign          sign of x, -1 for negative, 0 for 0, 1 for positive" "\n"\
"~. dyadic  insert        insert x between elts of y, 0~.1 2 3 is 1 0 2 0 3" "\n"\
"~: dyadic  notmatch      rank 0 version of ~ notequals" "\n"\
"<  monadic pred          x - 1" "\n"\
"<  dyadic  less          test whether x is lesser than y" "\n"\
"<. monadic floor         round x down" "\n"\
"<. dyadic  lesseq        test whether x is equal or lesser than y" "\n"\
"<: monadic gradedown     indices of array sorted descending" "\n"\
"<: dyadic  nudgeleft     shift elts of y to the left filling gap with x" "\n"\
">  monadic succ          x + 1" "\n"\
">  dyadic  greater       test whether x is greater than y" "\n"\
">. monadic ceil          round x up" "\n"\
">. dyadic  greatereq     test whether x is equal or greater than y" "\n"\
">: monadic gradeup       indices of array sorted ascending" "\n"\
">: dyadic  nudgeright    shift elts of y to the right filling gap with x" "\n"\
",  monadic enlist        put x into 1-elt array" "\n"\
",  dyadic  join          concat x and y" "\n"\
",. monadic enfile        same as , enlist but with infinite rank, ,.1 2 3 is (,1),:(,2),:(,3)" "\n"\
",. dyadic  enpair        put x and y into 2-elt array" "\n"\
"#  monadic count         yield count of elts of x" "\n"\
"#  dyadic  take          take x first elts of y (or last if x < 0)" "\n"\
"#. monadic where         #.0 0 1 0 1 0 is 2 4" "\n"\
"#. dyadic  copy          repeat each elt of x by corresponding number in y, 5 2 3 3#.0 2 2 1 is 2 2 3 3 3" "\n"\
"#: monadic group         #:'mississippi' is (,0),:1 4 7 10,:2 3 5 6,:8 9" "\n"\
"#: dyadic  buckets       group elts of y into buckets according to x, e.g. 0 -1 -1 2 0#:a b c d e is (a,.e),:(),:(,d)" "\n"\
"_  monadic nub           mark all unique elts of x, e.g. _'abracadabra' yields 1 1 1 0 1 0 1 0 0 0 0" "\n"\
"_  dyadic  drop          remove first x elts of y (or last if x < 0)" "\n"\
"_. monadic unbits        _.1 0 1 is 5" "\n"\
"_. dyadic  unbase        10_.4 5 6 is 456" "\n"\
"_: monadic bits          _:5 is 1 0 1" "\n"\
"_: dyadic  base          10_:4242 is 4 2 4 2" "\n"\
"?  monadic unique        distinct elts of x, same as ]#._" "\n"\
"?  dyadic  find          find all indices of x in y" "\n"\
"&  monadic flatten       flatten an array, same as ,//." "\n"\
"&  dyadic  minand        get min of two numbers (logical and for 0/1s)" "\n"\
"|  monadic reverse       reverse an array" "\n"\
"|  dyadic  maxor         get max of two numbers (for 0/1s is same as logical or)" "\n"\
"|. monadic round         round x" "\n"\
"|. dyadic  rotate        rotate array x times clockwise (-x for counterclockwise)" "\n"\
"|: monadic depth         find max depth of x, |:,,,y yields 3" "\n"\
"|: dyadic  windows       yields all contiguous x-sized subarrays of y" "\n"\
"@  monadic abs           |x|" "\n"\
"@  dyadic  at            pick elts from x by indices from y" "\n"\
"@. monadic shuffle       shuffle elts of x" "\n"\
"@. dyadic  member        check whether x is in y" "\n"\
"@: monadic infix         shortcut for }{:" "\n"\
"@: dyadic  indexof       yield index of x in y or #y if x not in y" "\n"\
"{  monadic head          first two elts of x, same as 2#" "\n"\
"{  dyadic  bin           bin search, e.g. 1 3 5 7 9{8 9 0 yields 3 4 -1" "\n"\
"{. monadic tail          last elt of x" "\n"\
"{: monadic prefixes      prefixes of x, same as |}.\\." "\n"\
"{: dyadic  shl           x << y" "\n"\
"}  monadic behead        all elts of x except first, same as 1_" "\n"\
"}  dyadic  xor           x ^ y" "\n"\
"}. monadic curtail       all elts of x except last, same as -1_" "\n"\
"}: monadic suffixes      suffixes of x, same as }.\\." "\n"\
"}: dyadic  shr           x >> y" "\n"\
"[  monadic factors       compute prime factors of x" "\n"\
"[  dyadic  left          yield x" "\n"\
"[. monadic bnot          ~x" "\n"\
"[. dyadic  bor           x | y" "\n"\
"[: monadic primes        find primes in range [2, x]" "\n"\
"[: dyadic  parts         split y into x parts" "\n"\
"]  monadic same          yield x (i.e. identity)" "\n"\
"]  dyadic  right         yield y (i.e. right argument)" "\n"\
"]. monadic sort          sort x ascending, shortcut for ]@>:" "\n"\
"]. dyadic  outof         the number of ways of picking x balls from a bag of y balls, e.g. 5].10 is 252" "\n"\
"]: monadic unsort        sort x descending, shortcut for ]@<:" "\n"\
"]: dyadic  explode       split y by delim x" "\n"\
"`. monadic symbol        cast x to a symbol" "\n"\
"`. dyadic  apply1        apply x to y" "\n"\
"`: monadic square        x ^ 2" "\n"\
"`: dyadic  apply2        apply x to y (y is 2-elt array of args)" "\n"\
"$  monadic shape         yield shape of x" "\n"\
"$  dyadic  reshape       reshape y to shape x" "\n"\
"$. monadic repr          yield string repr of x" "\n"\
"$. dyadic  format        format y by template x, e.g. '{0}+{1}*{-1}+_'$.1 2 3 4 is 1+2*4+1" "\n"\
"$: monadic eye           identity matrix of size x" "\n"\
"$: dyadic  implode       join y inserting x between" "\n"\
"";
cS V2HELP =\
"p. monadic print         print x" "\n"\
"P. monadic println       print x and a \\n" "\n"\
"s. monadic selfref1      monadic reference to current function or rhs of bind" "\n"\
"s. dyadic  selfref2      dyadic reference to current function or rhs of bind" "\n"\
"F. monadic read          read file (x=0 to read stdin)" "\n"\
"F. dyadic  write         write file (y=0 to write to stderr)" "\n"\
"t. monadic type          type of x, array=0, verb=1, symbol=2, number=3, char=4, nil=5, udf=6" "\n"\
"r. monadic deal          yield random elt of x" "\n"\
"r. dyadic  roll          roll xdy (note: y is 0-based, so >xr.y for 1-based)" "\n"\
"e. monadic eval          eval expression, yields udf on parse error" "\n"\
"i. monadic import        load and eval source file" "\n"\
"i. dyadic  foreign       call external function (lhs is array of arguments), e.g. .5i.'libm.so:dd:sin'" "\n"\
"y. monadic system        exec system command (yields output)" "\n"\
"y. dyadic  system2       exec system command with input" "\n"\
"E. monadic exit          exit with exit code" "\n"\
"L. dyadic  tackleft      prepend x to y" "\n"\
"R. dyadic  tackright     append x to y" "\n"\
"";
cS AHELP =\
"f\"         each          >\"1 2 3 yields 2 3 4" "\n"\
"xf\"        merge         1 2 3,\"a b c yields (1,.a),:(2,.b),:(3,.c)" "\n"\
"f\".        eachprior     -\".1 2 2 3 5 6 yields 1 0 1 2 1" "\n"\
"xf\".       eachpriorwith 0-\".1 2 2 3 5 6 yields 1 1 0 1 2 1" "\n"\
"f/         fold          +/1 2 3 yields 6" "\n"\
"xf/        foldwith      1+/1 2 3 yields 7" "\n"\
"f\\         scan          +\\1 2 3 yields 1 3 6" "\n"\
"xf\\        scanwith      1+\\1 2 3 yields 1 2 4 7" "\n"\
"f/.        converge      1;_/.1 2 3 yields ()" "\n"\
"f\\.        converges     1;_\\.1 2 3 yields 1 2 3,:2 3,:(,3),:()" "\n"\
"xf/.       eachright     1-/.1 2 3 yields 0 1 2" "\n"\
"xf\\.       eachleft      1-\\.1 2 3 yields 0 -1 -2" "\n"\
"f\":        rank          #\":1 2 3$1 yields 3 3, #\":inf 2 3$1 yields 1 1 1,:1 1 1" "\n"\
"xf\":       rank2         1 2 3 *:\":1 1 2 3 yields (,1),:2 2,:3 3 3" "\n"\
"n`         amend         'gw'0 3`'cross' yields 'grows'" "\n"\
"f&.        filter        >;0&.-2!.2 yields 1 2, basically shortcut for ]#.f" "\n"\
"f/:        span          =;' '/:'x y z' yields (,'x'),:(,'y'),:(,'z')" "\n"\
"xf/:       stencil       3+//:!10 yields 3 6 9 12 15 18 21 24, shortcut for f\"x|:" "\n"\
"f;.        reflex        *;.5 yields 25, 5%;.2 yields 0.4" "\n"\
"";
cS CHELP =\
"f;g        bond          */;!.5 yields 120, +;1 5 yields 6, 5;- 1 yields 4" "\n"\
"f?.x       pick          >;5?.((2*),:<)\"3 6 yields 6 5" "\n"\
"f?:F       while         <;5?:>0 yields 5" "\n"\
"n?:f       repeat        5?:*;2 1 yields 32" "\n"\
"f&:F       if            1+&:+2 yields 2" "\n"\
"f;:F       monaddyad     -;:+5 yields -5, 1-;:+5 yields 6" "\n"\
"";
cS IHELP =\
"inverse of a function f is a function ~f that undoes the effect of f" "\n"\
"\n"\
"f::~f  obverse  define inverse ~f for f" "\n"\
"\n"\
"f-:x       inverse       ~fx" "\n"\
"xf-:y      inverse2      (~fx)~f~fx" "\n"\
"f^:Fx      under         ~FfFx" "\n"\
"xf^:Fx     under2        ~F(Fx)f(Fx)" "\n"\
"";
cS SHELP =\
"/ comment" "\n"\
"5+5 / also comment" "\n"\
"5+5/not comment (no whitespace before /)" "\n"\
"nil udf                   / special, nil and undefined" "\n"\
"'a'%2                     / = nan, nan used to denote illegal numeric operation" "\n"\
"+1 2 3                    / = udf, attempt to transpose flat vector, udf/undefined used to denote illegal operation" "\n"\
"5 5.5 -5 42               / number (double-precision floats)" "\n"\
"1`000 1`000`000           /" "\n"\
".5 .429                   /" "\n"\
"0xff 0o4 0b0101           /" "\n"\
"nan inf                   /" "\n"\
"'a' 'b' 'g'               / chars (bytes)" "\n"\
"4t.0                      / 0 NUL byte" "\n"\
"(4t.0),:(4t.16),:(4t.22)  /" "\n"\
"1 2 3                     / numbers array" "\n"\
"'hello world!' 'bla''bla' / quote, array of chars" "\n"\
",'a'                      / 1-char string" "\n"\
",1                        / 1-elt array" "\n"\
"()                        / unit, empty array" "\n"\
"1,:(5+5),:1 2 3           / strand, mixed array literal" "\n"\
"-1                        / negative num literal" "\n"\
"- 1                       / application of - negate to 1" "\n"\
"-1 -2 -3                  / array of negative nums" "\n"\
"- 1 2 3                   / application of - negate to an array of nums" "\n"\
"5-5                       / array of numbers 5 and -5" "\n"\
"5- 5                      / 5 minus 5" "\n"\
"+                         / verb" "\n"\
"5+5                       / dyadic expr" "\n"\
"#1 2 3                    / monadic expr (no left side)" "\n"\
"+/ *;.                    / adverb" "\n"\
"+;1 -;* +^:^.             / conjunction" "\n"\
":x+y                      / function literal" "\n"\
":1                        / function that always yields 1" "\n"\
"x:123                     / bind name" "\n"\
"sq:*;.                    /" "\n"\
"fac:*/1+!                 / bind function" "\n"\
"f:x+y                     /" "\n"\
"f:-x                      / overload function by arity" "\n"\
"f 5                       / = -5" "\n"\
"5 f 5                     / = 10" "\n"\
"*/!.                      / hook, fgx -> f(g(x)), xfgy -> f(g(x, y))" "\n"\
"+/%#                      / fork, fghx -> g(f(x), h(x)), xfghy -> g(f(x), h(y))" "\n"\
"1+!                       / over, nfgx -> f(n, g(x)), xnfgy -> f(n, g(x, y))" "\n"\
"1+                        / bond, nfx -> f(n, x), xnfy -> f(n, f(x, y))" "\n";
cS HELP = "\\0\thelp on syntax\n"\
"\\+\thelp on verbs\n"\
"\\a\thelp on additional verbs\n"\
"\\\"\thelp on adverbs\n"\
"\\;\thelp on conjunctions\n"\
"\\-:\thelp on inverses\n";
cS VSTR=VER " " __DATE__;
V jkexec(St*st,FILE*fd,B isrepl,S*s){Vt*v=N;
  LOOP{Bt*buffer;
    C line[256];
    buffer=Bnew();
    if(isrepl)putc('\t',stdout);
    if(!fgets(line,SO(line),fd))BR;
    if(isrepl){if(strcmp(line,"\\\\\n")==0)BR;
      elif(strcmp(line,"\\\n")==0){printf("%s",HELP);CN;}
      elif(strcmp(line,"\\0\n")==0){printf("%s",SHELP);CN;}
      elif(strcmp(line,"\\+\n")==0){printf("%s",VHELP);CN;}
      elif(strcmp(line,"\\a\n")==0){printf("%s",V2HELP);CN;}
      elif(strcmp(line,"\\\"\n")==0){printf("%s",AHELP);CN;}
      elif(strcmp(line,"\\;\n")==0){printf("%s",CHELP);CN;}
      elif(strcmp(line,"\\-:\n")==0){printf("%s",IHELP);CN;}}
    WH(strlen(line)>2&&strcmp(line+strlen(line)-3,"..\n")==0){line[strlen(line)-3]=0;
      BappendS(buffer,line);
      if(isrepl)putc('\t',stdout);
      if(!fgets(line,SO(line),fd))R;}
    BappendS(buffer,line);
    *s=Bread(buffer);
    v=Srun(st,*s);
    FR(*s);*s=N;
    if(isrepl&&v->tag!=NIL){Tset(st->env,"it",v);
      S s=Vshow(v);
      fputs(s,stdout);
      FR(s);
      if(isrepl)putc('\n',stdout);}}
  if(!isrepl&&v&&v->tag!=NIL){S s=Vshow(v);
    fputs(s,stdout);
    FR(s);}}
I main(I argc,S*argv){GC_INIT();
  GC_enable_incremental();
  guards=An();
  Iin=isatty(0);
  HASH_SEED=time(N);
  srand(HASH_SEED);
  VCACHE=Tnew();
  SCACHE=Tnew();
  for(Z i=0;i<AE(VERBS);i++){Vt*v=VnC(VERB);
    v->val.verb=&VERBS[i];
    Tset(VCACHE,VERBS[i].name,v);}
  _UNIT=Vnew(ARRAY);
  _UNIT->val.array=An();
  St*st=Sn();
  for(I i=1;i<=8;i++){NNUMS[i-1]=VnC(NUM);
    NNUMS[i-1]->val.number=-i;}
  for(I i=0;i<256;i++){NUMS[i]=VnC(NUM);
    NUMS[i]->val.number=i;}
  for(I i=0;i<256;i++){CHARS[i]=VnC(CHAR);
    CHARS[i]->val._char=i;}
  _NAN=VnC(NUM);
  _NAN->val.number=NAN;
  INF=VnC(NUM);
  INF->val.number=INFINITY;
  NINF=VnC(NUM);
  NINF->val.number=-INFINITY;
  Ar*vs=An();
  for(Z i=0;i<strlen(VSTR);i++)Ap(vs,CHARS[VSTR[i]]);
  Tset(st->env,"JKV",Vna(vs));
  Tset(st->env,"E",Vnn(exp(1)));
  Tset(st->env,"pi",Vnn(M_PI));
  Tset(st->env,"tau",Vnn(M_PI*2));
  Tset(st->env,"nan",_NAN);
  Tset(st->env,"inf",INF);
  Tset(st->env,"nil",st->nil);
  Tset(st->env,"udf",st->udf);
  Inverses=Tnew();
  Tset(Inverses,"+",Gv("+"));
  Tset(Inverses,"-",Gv("-"));
  Tset(Inverses,"|",Gv("|"));
  Tset(Inverses,"~",Gv("~"));
  Tset(Inverses,"%",Gv("%"));
  Tset(Inverses,"]",Gv("]"));
  Tset(Inverses,"*:",Gv("%:"));
  Tset(Inverses,"%:",Gv("*:"));
  Tset(Inverses,">",Gv("<"));
  Tset(Inverses,"<",Gv(">"));
  Tset(Inverses,"_.",Gv("_:"));
  Tset(Inverses,"_:",Gv("_."));
  Tset(Inverses,"^.",Gv("^"));
  Tset(Inverses,"^",Gv("^."));
  Tset(Inverses,"+;.",Gv("%:"));
  Tset(Inverses,"*/",Gv("["));
  Tset(Inverses,"[",CV("*/"));
  Tset(Inverses,"!",CV(">|/"));
  Tset(Inverses,"!.",CV("|/"));
  Tset(Inverses,"]@>:",CV("]@<:"));
  Tset(Inverses,"]@<:",CV("]@>:"));
  Ar*args=An();
  for(I i=1;i<argc;i++){Ar*arg=An();
    S s=argv[i];
    WH(*s)Ap(arg,CHARS[*s++]);
    Ap(args,Vna(arg));}
  Tset(st->env,"args",Vna(args));
  if(Iin)printf("jk\t\\\\ to exit  \\ for help\n");
  S s=N;
  if(Iin)setjmp(Icp);
  if(s){FR(s);s=N;}
  jkexec(st,stdin,Iin,&s);}