jk/jk.c

/* 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>
#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 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)
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;
#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
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 _Lst Lst;
struct _Lst{P value;
  Lst*next;};
Lst*ln(void){Lst*list=ma(SO(Lst));
  list->value=N;
  list->next=N;R list;}
B le(Lst*list){R(!(list)->value);}
Z ll(Lst*list){Z length=0;
  if(le(list))R length;
  do{list=list->next,length++;}WH(list);R length;}
P li(Lst*list,SZ index){Z length;
  if(le(list))R N;
  if(index==0)R list->value;
  length=ll(list);
  if(index<0)index+=((SZ)length);
  if(index<0||index>=length)R N;
  for(Z i=0;i<((Z)index);i++)list=list->next;R list->value;}
Lst*lp(Lst*list,P value){Lst*head=list;
  if(le(list)){list->value=value;R head;}
  WH(list->next)list=list->next;
  list=list->next=ln();
  list->value=value;R head;}
Lst*lc(Lst*l){Lst*r=ln();
  if(!le(l))WH(l){lp(r,l->value);
      l=l->next;}
  R r;}
P lP(Lst*list){if(le(list))R N;
  if(!list->next){P value=list->value;
    list->value=N;R value;}
  Lst*head=list;
  WH(list){if(!list->next){P value=list->value;
      list->value=N;
      head->next=N;R value;}
    head=list;
    list=list->next;}
  R N;}
P ls(Lst*list,SZ index,P value){Z length=ll(list);
  if(index<0)index+=((SZ)length);
  if(index==((SZ)length)){lp(list,value);R value;}
  if(index<0||index>=length)R N;
  for(Z i=0;i<((Z)index);i++)list=list->next;
  list->value=value;R value;}
Lst*lI(Lst**list,SZ index,P value){Lst*head=*list;
  if(index==-1)R lp(head,value);
  Z length=ll(head);
  if(index<0)index+=(SZ)length;
  if(index<0||index>length)R N;
  if(index==-1)R lp(head,value);
  if(index==0){if(le(head))R lp(head,value);
    Lst*temp=ln();
    temp->value=value;
    temp->next=head;
   *list=temp;R temp;}
  Lst*temp0=*list;
  for(Z i=0;i<((Z)index)-1;i++)temp0=temp0->next;
  Lst*temp=temp0->next;
  temp0->next=ln();
  temp0->next->value=value;
  temp0->next->next=temp;R head;}
Lst*ld(Lst**list,SZ index){Lst*head=*list;
  if(le(head))R N;
  Z length=ll(head);
  if(index<0)index+=(SZ)length;
  if(index<0||index>=length)R N;
  if(index==0){head->value=N;
    if(!head->next)R head;
   *list=head->next;R*list;}
  Lst*temp0=*list;
  for(Z i=0;i<((Z)index)-1;i++)temp0=temp0->next;
  Lst*temp=temp0->next;
  temp->value=N;
  temp0->next=temp->next;R head;}
Lst*lS(Lst*list,bool(*cmp)(P ,P )){Z l=ll(list);
  B s;
  for(Z i=0;i<l;i++){Lst*t=list;
    Lst*p=list;
    s=F;
    WH(t->next){Lst*n=t->next;
      if(cmp(t->value,n->value)){s=T;
        if(t==list){t->next=n->next;
          n->next=t;
          p=n;
          list=p;}else{t->next=n->next;
          n->next=t;
          p->next=n;
          p=n;}
        CN;}
      p=t;
      t=t->next;}
    if(!s)BR;}
  R list;}
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_QUOTE}tag;
  S text;}Tkt;
typedef struct{S source;
  Z len;
  Z pos;
  Lst*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;
  lp(lexer->tokens,token);}
Lst*guards;
jmp_buf*guard(){jmp_buf*lb=maa(SO(jmp_buf));
  lp(guards,lb);R lb;}
jmp_buf*guarding(){R li(guards,-1);}
V unguard(){jmp_buf*lb=lP(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));}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=ln();
  WH(lexer->pos<lexer->len){C c=Llook(lexer,0);
    if(c=='/'&&le(lexer->tokens))BR;
    if(isspace(c)){Leat(lexer);
      if(Llook(lexer,0)=='/')BR;}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 U32*blocks=(const U32*)(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;}
typedef struct _Vt Vt;
typedef struct _St St;
typedef struct _vt vt;
struct _St{Tt*env;
  Lst*args;
  Lst*selfrefs;
  Vt*nil;
  Vt*udf;
  Vt*unit;
  vt*at;};
struct _vt{S name;
  UI rank[3];
  Lst*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{Lst*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(Lst*array){if(le(array)){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;}
Vt*Vnc(UC _char){R CHARS[_char];}
B Veq(Vt*x,Vt*y){if(xt!=yt)R F;
  SW(xt){CS ARRAY:{Lst*tx=xa;
    Lst*ty=ya;
    if(le(tx)&&le(ty))BR;
    if(le(tx)&&!le(ty))R F;
    if(!le(tx)&&le(ty))R F;
    WH(tx){if(!ty)R F;
      if(!Veq(tx->value,ty->value))R F;
      tx=tx->next;
      ty=ty->next;}
    if(ty)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(Lst*a){if(le(a))R F;
  WH(a){Vt*v=a->value;
    if(v->tag!=CHAR||!isprint(v->val._char))R F;
    a=a->next;}
  R T;}
B Aap(Lst*a){if(le(a))R F;
  WH(a){Vt*v=a->value;
    if(v->tag!=ARRAY)R F;
    a=a->next;}
  R T;}
S Vshow(Vt*v);
S show_array(Vt*v){if(v->tag!=ARRAY)R Vshow(v);
  Lst*t=v->val.array;
  if(le(t))R sdup("()");
  Bt*buf=Bnew();
  if(!t->next){Bappend(buf,',');
    S ts=Vshow(t->value);
    BappendS(buf,ts);
    FR(ts);R Bread(buf);}
  if(Cap(t)){WH(t){Vt*c=t->value;
      Bappend(buf,c->val._char);
      t=t->next;}
    R Bread(buf);}
  if(!Aap(t)){WH(t){S ts=Vshow(t->value);
      BappendS(buf,ts);
      FR(ts);
      t=t->next;
      if(t)Bappend(buf,' ');}}else{UI rwk=0;
    UI rwl=ll(t->value);
    WH(t){S ts=show_array(t->value);
      BappendS(buf,ts);
      FR(ts);
      t=t->next;
      if(t)Bappend(buf,' ');
      rwk++;
      if(rwk>=rwl&&t){rwk=0;
        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("<?>");}
D Vnum(Vt*v){if(v->tag==CHAR)R v->val._char;R vn;}
B VTp(Vt*x){SW(xt){CS ARRAY:R !le(xa);
  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=ln();
  st->selfrefs=ln();
  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)lp(st->selfrefs,f);
    Vt*r=f->monad(st,f,x);
    if(f->mark)lP(st->selfrefs);R r;}
  Lst*t=xa;
  if(le(t))R x;
  Lst*l=ln();
  WH(t){lp(l,eR(st,f,t->value,d+1,rm));
    t=t->next;}
  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)lp(st->selfrefs,f);
    Vt*r=f->dyad(st,f,x,y);
    if(f->mark)lP(st->selfrefs);R r;}
  if(dl<rl&&dr<rr&&xt==ARRAY&&yt==ARRAY){Lst*tx=xa;
    Lst*ty=ya;
    if(!tx->value||!ty->value)R !tx->value?x:y;
    Lst*t=ln();
    WH(tx){if(!ty)BR;
      lp(
          t,tgth(st,f,tx->value,ty->value,dl+1,dr+1,rl,rr));
      tx=tx->next;
      ty=ty->next;}
    R Vna(t);}elif((xt!=ARRAY||dl>=rl)&&yt==ARRAY&&dr<rr){Lst*ty=ya;
    if(!ty->value)R y;
    Lst*t=ln();
    WH(ty){lp(t,tgth(st,f,x,ty->value,dl,dr+1,rl,rr));
      ty=ty->next;}
    R Vna(t);}elif((yt!=ARRAY||dr>=rr)&&xt==ARRAY&&dl<rl){Lst*tx=xa;
    if(!tx->value)R x;
    Lst*t=ln();
    WH(tx){lp(t,tgth(st,f,tx->value,y,dl+1,dr,rl,rr));
      tx=tx->next;}
    R Vna(t);}
  if(f->mark)lp(st->selfrefs,f);
  Vt*r=f->dyad(st,f,x,y);
  if(f->mark)lP(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;
  Lst*l;
  Nt*a;
  Nt*b;
  Nt*c;};
Vt*_fork_m(St*st,vt*self,Vt*x){vt*f=li(self->bonds,0);
  vt*g=li(self->bonds,1);
  vt*h=li(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=li(self->bonds,0);
  vt*g=li(self->bonds,1);
  vt*h=li(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=li(self->bonds,0);
  vt*g=li(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=li(self->bonds,0);
  vt*g=li(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=li(self->bonds,0);
  Vt*g=li(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=li(self->bonds,0);
  Vt*g=li(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=li(self->bonds,0);
  vt*g=li(self->bonds,1);
  vt*h=li(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=li(self->bonds,0);
  vt*g=li(self->bonds,1);
  vt*h=li(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,UI*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){Lst*t=node->l;
    WH(t){if(nca(t->value,argc))R T;
      t=t->next;}}
  R F;}
Vt*Swalk(St*st,Nt*node);
Vt*_const_m(St*st,vt*self,Vt*x){R self->bonds->value;}
Vt*_const_d(St*st,vt*self,Vt*x,Vt*y){R self->bonds->value;}
Vt*_fun_m(St*st,vt*self,Vt*x){Lst*args=ln();
  lp(args,x);
  lp(args,self);
  lp(st->args,args);
  Vt*r=Swalk(st,self->bonds->value);
  lP(st->args);
  FR(args);R r;}
Vt*_fun_d(St*st,vt*self,Vt*x,Vt*y){Lst*args=ln();
  lp(args,x);
  lp(args,y);
  lp(args,self);
  lp(st->args,args);
  Vt*r=Swalk(st,self->bonds->next->value);
  lP(st->args);
  FR(args);R r;}
Vt*_partial_conjunction(St*st,vt*self,Vt*x){advt*av=self->bonds->value;
  Vt*a=self->bonds->next->value;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:{Lst*t=node->l;
    WH(t){t->value=Swalk(st,t->value);
      t=t->next;}
    R Vna(node->l);}
  CS N_LITERAL:{Vt*v=node->v;
    Vt*t=N;
    if(v->tag==SYM){S n=v->val.symbol;
      if(!le(st->args)){Lst*args=li(st->args,-1);
        Z argc=ll(args)-1;
        if(argc==2&&strcmp(n,"y")==0)R args->next->value;
        elif(strcmp(n,"x")==0)R args->value;}
      if((t=Tget(st->env,n)))R t;}
    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=ln();
    nv->name=sdup(argc==0?":...":argc==1?":x":":xy");
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    if(argc==0){lp(nv->bonds,Swalk(st,node->a));
      nv->monad=_const_m;
      nv->dyad=_const_d;}elif(argc==1){lp(nv->bonds,node->a);
      nv->monad=_fun_m;
      nv->dyad=N;}else{nv->monad=N;
      lp(nv->bonds,st->udf);
      lp(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);R Vnv(node->av->adverb(st,v));}
  CS N_CONJ:{Vt*v1=Swalk(st,node->a);
    Vt*v2=Swalk(st,node->b);R Vnv(node->av->conjunction(st,v1,v2));}
  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=ln();
    lp(nv->bonds,node->av);
    lp(nv->bonds,a);
    nv->rank[0]=0;
    nv->rank[1]=0;
    nv->rank[2]=0;
    nv->monad=_partial_conjunction;
    nv->dyad=N;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=ln();
    lp(nv->bonds,f);
    lp(nv->bonds,g);
    lp(nv->bonds,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;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=ln();
    lp(nv->bonds,f);
    lp(nv->bonds,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;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=ln();
    lp(nv->bonds,f);
    lp(nv->bonds,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;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=ln();
    lp(nv->bonds,f);
    lp(nv->bonds,g);
    lp(nv->bonds,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;R Vnv(nv);}
  CS N_BIND:{Vt*l=node->a->v;
    Nt*b=node->b;
    UI argc=0;
    nca(b,&argc);
    if(argc!=0)b=Nn1(N_FUN,b);
    Vt*r=Swalk(st,b);
    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){ls(ov->val.verb->bonds,0,r->val.verb->bonds->value);
        ov->val.verb->monad=r->val.verb->monad;BR;}
      if(!ov->val.verb->dyad&&r->val.verb->dyad){lp(ov->val.verb->bonds,r->val.verb->bonds->next->value);
        ov->val.verb->dyad=r->val.verb->dyad;BR;}}
    Tset(st->env,l->val.symbol,r);}}
  R st->nil;}
Vt*vconst(St*st,vt*self,Vt*x){vt*nv=vnew();
  nv->bonds=ln();
  lp(nv->bonds,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=_const_m;
  nv->dyad=_const_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*vobverse(St*st,vt*self,Vt*x,Vt*y){if(xt==VERB&&yt==VERB){vt*vx=xV;
    if(!yV->monad)
      R st->udf;
    if(strcmp(vx->name,":...")==0||strcmp(vx->name,":x")==0||strcmp(vx->name,":xy")==0)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||le(xa))R st->udf;
  Lst*t=xa;
  if(!Aap(t))R st->udf;
  Lst*r=ln();
  Vt*c0=t->value;
  Lst*c0t=c0->val.array;
  Z c0l=ll(c0t);
  for(Z i=0;i<c0l;i++){Lst*nc=ln();
    Lst*t2=t;
    WH(t2){Vt*rw=t2->value;
      Lst*rwt=rw->val.array;
      if(le(rwt))R st->udf;
      Vt*v=li(rwt,i);
      if(!v)v=rwt->value;
      lp(nc,v);
      t2=t2->next;}
    lp(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(le(xa))R st->udf;R xa->value;}
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);
    Lst*r=ln();
    WH(k--)lp(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 is_bad_num(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(le(xa)||!xa->next)R st->udf;
  Z p=1;
  Z xl=0;
  Lst*t=xa;
  WH(t){Vt*it=t->value;
    if(it->tag!=NUM||is_bad_num(it->val.number))R st->udf;
    p*=(Z)(it->val.number);
    t=t->next;xl++;}
  if(p<1)R st->unit;
  t=xa;
  U64*lims=maa(SO(U64)*xl);
  for(Z i=0;i<xl;i++){lims[i]=(Z)(((Vt*)t->value)->val.number);
    t=t->next;}
  U64**z=ma(SO(U64*)*p);
  for(Z i=0;i<p;i++)z[i]=maa(SO(U64)*xl);
  for(Z i=0;i<p-1;i++){U64*r=z[i];
    U64*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);
  Lst*r=ln();
  for(Z i=0;i<p;i++){Lst*rw=ln();
    for(Z j=0;j<xl;j++)lp(rw,Vnn(z[i][j]));
    lp(r,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(le(ya))R y;
  Lst*r=ln();
  Z l=ll(ya);
  Z cl=fabs(xn);
  for(Z i=0;i<l;i+=cl)lp(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);
    Lst*r=ln();
    for(I i=0;i<bk;i++)if((n &(1 << i))>> i)lp(r,NUMS[1]);
      else lp(r,NUMS[0]);R Vna(r);}
  R st->udf;}
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;
    Lst*r=ln();
    WH(v>0){r=lI(&r,0,Vnn(v%b));
      v/=b;}
    R Vna(r);}
  R st->udf;}
SZ indexOf(Lst*l,Vt*x){if(le(l))R -1;
  Z i=0;
  WH(l){if(Veq(l->value,x))R i;
    l=l->next;
    i++;}
  R -1;}
Vt*vgroup(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  Lst*r=ln();
  Lst*is=ln();
  Z i=0;
  Lst*t=xa;
  WH(t){Vt*v=t->value;
    SZ n=indexOf(is,v);
    if(n<0){lp(r,venlist(st,N,Vnn(i)));
      lp(is,v);}else{Vt*tmp=li(r,n);
      lp(tmp->val.array,Vnn(i));}
    t=t->next;
    i++;}
  WH(is){Lst*tmp=is->next;
    FR(is);
    is=tmp;}
  R Vna(r);}
Vt*vbuckets(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R y;
  if(yt!=ARRAY)y=venlist(st,N,x);
  elif(le(ya))R y;
  Lst*r=ln();
  Lst*t=xa;
  Z mx=0;
  WH(t){Vt*v=t->value;
    if(v->tag!=NUM)BR;
    SZ i=vn;
    if(i>=0&&i>mx)mx=i;
    t=t->next;}
  for(Z i=0;i<mx+1;i++)lp(r,ln());
  if(le(r)){FR(r);R st->unit;}
  Lst*ty=ya;
  t=xa;
  WH(t&&ty){Vt*v=t->value;
    if(v->tag!=NUM)BR;
    SZ i=vn;
    if(i>=0){Lst*b=li(r,i);
      if(b)lp(b,ty->value);}
    t=t->next;ty=ty->next;}
  if(ty){Lst*lb=ln();
    WH(ty){lp(lb,ty->value);
      ty=ty->next;}
    lp(r,lb);}
  t=r;
  WH(t){t->value=Vna(t->value);
    t=t->next;}
  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||le(xa)||!xa->next)R x;
  Lst* permutation=lc(xa);
  Z length=ll(permutation);
  Lst*result=ln();
  lp(result,lc(permutation));
  Lst*c=ln();
  for(Z i=0;i<length;i++){Z*n=maa(SO(Z));
    
    lp(c,n);}
  Z k;
  Lst*p;
  Z i=0;
  WH(i<length){Z*n=li(c,i);
    if((*n)<i){k=i%2&&(*n);
      p=li(permutation,i);
      ls(permutation,i,li(permutation,k));
      ls(permutation,k,p);
     *n=(*n)+1;
      i=1;
      lp(result,lc(permutation));}else{*n=0;
      i++;}}
  WH(c){Lst*tmp=c->next;
    FR(c->value);
    FR(c);
    c=tmp;}
  WH(permutation){Lst*tmp=permutation->next;
    FR(permutation);
    permutation=tmp;}
  Lst*t=result;
  WH(t){t->value=Vna(t->value);
    t=t->next;}
  R Vna(result);}
Vt*voccurences(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  Lst*table=ln();
  Lst*r=ln();
  Lst*t=xa;
  WH(t){B f=F;
    Vt*it=t->value;
    Lst*tt=table;
    if(!le(tt))WH(tt){Lst*p=tt->value;
        if(Veq(p->value,it)){Z*n=p->next->value;
         *n=(*n)+1;
          lp(r,Vnn(*n));
          f=T;BR;}
        tt=tt->next;}
    if(!f){Lst*p=ln();
      lp(p,it);
      Z*n=maa(SO(Z));
      lp(p,n);
      lp(table,p);
      lp(r,NUMS[0]);}
    t=t->next;}
  if(!le(table)){t=table;
    WH(t){Lst*tmp=t->next;
      Lst*p=t->value;
      FR(p->next->value);
      FR(p->next);
      FR(p);
      FR(t);
      t=tmp;}}
  R Vna(r);}
Vt*vmask(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  if(yt!=ARRAY)y=venlist(st,N,y);
  Lst*r=ln();
  Vt*l=Vnn(ll(ya));
  Z n=0;
  Z k=ll(xa);
  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++)lp(r,Vnn(n));
      i--;}else lp(r,NUMS[0]);}
  R Vna(r);}
Vt*vclassify(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  Lst*table=ln();
  Lst*r=ln();
  Lst*t=xa;
  Z i=0;
  WH(t){B f=F;
    Vt*it=t->value;
    Lst*tt=table;
    if(!le(tt))WH(tt){Lst*p=tt->value;
        if(Veq(p->value,it)){Z*n=p->next->value;
          lp(r,Vnn(*n));
          f=T;BR;}
        tt=tt->next;}
    if(!f){Lst*p=ln();
      lp(p,it);
      Z*n=maa(SO(Z));
     *n=i++;
      lp(p,n);
      lp(table,p);
      lp(r,Vnn(*n));}
    t=t->next;}
  if(!le(table)){t=table;
    WH(t){Lst*tmp=t->next;
      Lst*p=t->value;
      FR(p->next->value);
      FR(p->next);
      FR(p);
      FR(t);
      t=tmp;}}
  R Vna(r);}
Vt*vunbits(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  I n=0;
  I i=0;
  Lst*t=xa;
  WH(t){if(VTp(t->value))n|=(int)1 << i;
    else n &= ~((int)1 << i);
    t=t->next;
    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;
    Lst*t=ya;
    if(le(t))R st->udf;
    WH(t){Vt*v=t->value;
      if(v->tag!=NUM)BR;
      Z k=fabs(vn);
      n=n*b+k;
      t=t->next;}
    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;}
B _compare_up(P a,P b){Vt*x=((Lst*)a)->value;
  Vt*y=((Lst*)b)->value;
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)>Vnum(y))R T;R F;}
  R F;}
B _compare_down(P a,P b){Vt*x=((Lst*)a)->value;
  Vt*y=((Lst*)b)->value;
  if((xt==NUM||xt==CHAR)&&(yt==NUM||yt==CHAR)){if(Vnum(x)<Vnum(y))R T;R F;}
  R F;}
Vt*_grade(Vt*x,B down){if(xt!=ARRAY||le(xa)||!xa->next)R x;
  Z i=0;
  Lst*ps=ln();
  Lst*t=xa;
  WH(t){Lst*p=ln();
    lp(p,t->value);
    lp(p,Vnn(i++));
    lp(ps,p);
    t=t->next;}
  ps=lS(ps,down?_compare_down:_compare_up);
  t=ps;
  WH(t){Lst*p=t->value;
    t->value=p->next->value;
    FR(p->next);
    FR(p);
    t=t->next;}
  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(xt!=ARRAY)R venlist(st,N,y);
  elif(le(xa))R x;
  elif(!xa->next)R venlist(st,N,y);
  Lst*r=ln();
  Lst*t=xa->next;
  WH(t){lp(r,t->value);
    t=t->next;}
  lp(r,y);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(xt!=ARRAY)R venlist(st,N,y);
  elif(le(xa))R x;
  elif(!xa->next)R venlist(st,N,y);
  Lst*r=ln();
  lp(r,y);
  Lst*t=xa;
  WH(t->next){lp(r,t->value);
    t=t->next;}
  R Vna(r);}
Vt*venlist(St*st,vt*self,Vt*x){Lst*l=ln();
  lp(l,x);R Vna(l);}
Vt*vjoin(St*st,vt*self,Vt*x,Vt*y){Lst*l=ln();
  if(xt==ARRAY&&!le(xa)){Lst*t=xa;
    WH(t){lp(l,t->value);
      t=t->next;}}else lp(l,x);
  if(yt==ARRAY&&!le(ya)){Lst*t=ya;
    WH(t){lp(l,t->value);
      t=t->next;}}else lp(l,y);R Vna(l);}
Vt*venpair(St*st,vt*self,Vt*x,Vt*y){Lst*l=ln();
  lp(l,x);
  lp(l,y);R Vna(l);}
Vt*vselfref1(St*st,vt*self,Vt*x){vt*v;
  if(!le(st->args))v=li(li(st->args,-1),-1);
  elif(!le(st->selfrefs))v=li(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(!le(st->args))v=li(li(st->args,-1),-1);
  elif(!le(st->selfrefs))v=li(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||le(ya))R st->unit;
    B rev=xn<0;
    Z k=(Z)fabs(xn);
    Lst*t=ya;
    Lst*r=ln();
    if(rev)for(SZ i=k;i>0;i--){Vt*v=li(t,-i);
        if(!v)CN;
        lp(r,v);}
    else WH(t&&k){lp(r,t->value);
        t=t->next;
        k--;}
    R Vna(r);}
  R st->udf;}
Vt*vwhere(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  Lst*r=ln();
  Lst*t=xa;
  Z i=0;
  WH(t){Vt*a=t->value;
    if(a->tag!=NUM)BR;
    Z k=fabs(a->val.number);
    for(Z j=0;j<k;j++)lp(r,Vnn(i));
    t=t->next;
    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);
  Lst*tx=xa;
  Lst*ty=ya;
  if(le(tx)||le(ty))R st->unit;
  Lst*r=ln();
  WH(tx){Vt*a=tx->value;
    Vt*b=ty->value;
    if(b->tag!=NUM)BR;
    Z k=fabs(b->val.number);
    for(Z i=0;i<k;i++)lp(r,a);
    tx=tx->next;
    if(ty->next)ty=ty->next;}
  R Vna(r);}
Vt*vnub(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R x;
  Lst*n=ln();
  Lst*r=ln();
  Lst*t=xa;
  WH(t){B u=T;
    Lst*t2=r;
    if(!le(t2))WH(t2){if(Veq(t->value,t2->value)){u=F;BR;}
        t2=t2->next;}
    if(u)lp(r,t->value);
    lp(n,u?NUMS[1]:NUMS[0]);
    t=t->next;}
  WH(r){Lst*tmp=r->next;
    FR(r);
    r=tmp;}
  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(le(ya))R st->unit;
    B rev=xn<0;
    Z k=(Z)fabs(xn);
    Lst*t=ya;
    if(rev){Z l=ll(t);
      if(k>=l)R st->unit;R vtake(st,N,Vnn(l-k),y);}
    Lst*r=ln();
    WH(t&&k){t=t->next;
      k--;}
    WH(t){lp(r,t->value);
      t=t->next;}
    R Vna(r);}
  R st->udf;}
Vt*vunique(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R x;
  Lst*r=ln();
  Lst*t=xa;
  WH(t){B u=T;
    Lst*t2=r;
    if(!le(t2))WH(t2){if(Veq(t->value,t2->value)){u=F;BR;}
        t2=t2->next;}
    if(u)lp(r,t->value);
    t=t->next;}
  R Vna(r);}
Vt*vfind(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,self,y);
  elif(le(ya))R st->unit;
  Z i=0;
  Lst*r=ln();
  Lst*t=ya;
  WH(t){if(Veq(t->value,x))lp(r,Vnn(i));
    t=t->next;
    i++;}
  R Vna(r);}
Vt*vcount(St*st,vt*self,Vt*x){if(xt!=ARRAY)R NUMS[1];R Vnn(ll(xa));}
V flatten(Vt*v,Lst*r){if(v->tag==ARRAY){Lst*t=v->val.array;
    WH(t){flatten(t->value,r);
      t=t->next;}}else lp(r,v);}
Vt*vflatten(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R x;
  Lst*r=ln();
  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;
  Lst*t=xa;
  if(le(t))R x;
  Lst*r=ln();
  for(SZ i=ll(t)-1;i>=0;i--)lp(r,li(t,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(xt!=ARRAY||le(xa)||!xa->next)R x;
  if(yt!=NUM)R st->udf;
  B rev=yn<0;
  Z k=fabs(yn);
  Lst*r=ln();
  Lst*t=xa;
  WH(t){lp(r,t->value);
    t=t->next;}
  for(Z i=0;i<k;i++){Vt*v;
    if(rev){v=r->value;
      r=r->next;
      lp(r,v);}else{v=lP(r);
      r=lI(&r,0,v);}}
  R Vna(r);}
Vt*vwindows(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(le(ya))R y;
  Z k=fabs(xn);
  Z l=ll(ya);
  Lst*r=ln();
  for(Z i=0;i<l;i++){if(i+k>l)BR;
    lp(r,vtake(st,N,Vnn(k),vdrop(st,N,Vnn(i),y)));}
  R Vna(r);}
Z depthOf(Vt*x,Z d){if(xt==ARRAY){Lst*t=xa;
    if(le(t))R 0;
    WH(t){Z d2=depthOf(t->value,d+1);
      if(d2>d)d=d2;
      t=t->next;}
    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(le(xa))R st->nil;
  Vt*v=li(xa,(SZ)yn);
  if(!v)R st->udf;R v;}
Vt*vmember(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(le(xa))R NUMS[0];
  Lst*t=xa;
  WH(t){if(Veq(t->value,y))R NUMS[1];
    t=t->next;}
  R NUMS[0];}
Vt*vshuffle(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(le(xa))R x;
  Lst*t=xa;
  Z l=0;
  Lst*r=ln();
  WH(t){lp(r,t->value);
    t=t->next;l++;}
  for(Z i=0;i<l;i++){Z j=rand()%l;
    Vt*tmp=li(r,i);
    ls(r,i,li(r,j));
    ls(r,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(le(xa))R x;
  if(yt!=ARRAY)y=venlist(st,self,x);
  elif(le(ya))R y;
  Z xl=ll(xa);
  Lst*bins=ln();
  for(Z i=0;i<xl;i++){D s;
    D e;
    Vt*vs=li(xa,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): li(xa,i+1);
    if(ve->tag==NUM)e=fabs(ve->val.number);
    elif(ve->tag==CHAR)e=ve->val._char;
    else R st->udf;
    if(ll(bins)>0){Lst*pp=li(bins,-1);
      D*pe=pp->value;
      if(s<=(*pe))R st->udf;}
    D*sn=ma(SO(D));
   *sn=s;
    D*en=ma(SO(D));
   *en=e;
    Lst*p=ln();
    lp(p,sn);
    lp(p,en);
    lp(bins,p);}
  Z bl=ll(bins);
  Lst*r=ln();
  Z yl=ll(ya);
  for(Z i=0;i<yl;i++){Vt*it=li(ya,i);
    D itv;
    if(it->tag==NUM)itv=it->val.number;
    elif(it->tag==CHAR)itv=it->val._char;
    else R st->udf;
    Lst*b=bins->value;
    D*s=b->value;
    if(itv<(*s)){lp(r,NNUMS[0]);CN;}
    b=li(bins,-1);
    s=b->next->value;
    if(itv>=(*s)){lp(r,Vnn(bl-1));CN;}
    D v=NAN;
    for(Z j=0;j<bl;j++){b=li(bins,j);
      D*s=b->value;
      D*e=b->next->value;
      if(itv>=(*s)&&itv<(*e)){v=j;BR;}}
    if(!isnan(v))lp(r,Vnn(v));}
  WH(bins){Lst*tmp=bins->next;
    Lst*b=bins->value;
    FR(b->next->value);
    FR(b->next);
    FR(b->value);
    FR(b);
    FR(bins);
    bins=tmp;}
  R Vna(r);}
Vt*vtail(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  if(le(xa))R st->udf;R li(xa,-1);}
Vt*vcut(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,self,x);
  elif(le(xa))R x;
  if(yt!=ARRAY)y=venlist(st,self,x);
  elif(le(ya))R x;
  if(ll(xa)!=2)R st->udf;
  Vt*vs=xa->value;
  Vt*ve=xa->next->value;
  if(vs->tag!=NUM||ve->tag!=NUM)R st->udf;
  Z s=fabs(vs->val.number);
  Z e=fabs(ve->val.number);
  Lst*r=ln();
  Z l=ll(ya);
  Lst*pa=ln();
  for(Z i=s;i<e&&i<l;i++){Vt*v=li(ya,i);
    if(!v)BR;
    lp(pa,v);}
  Lst*pb=ln();
  for(Z i=e;i<l;i++){Vt*v=li(ya,i);
    if(!v)BR;
    lp(pb,v);}
  lp(r,Vna(pa));
  lp(r,Vna(pb));R Vna(r);}
Vt*vprefixes(St*st,vt*self,Vt*x){if(xt!=ARRAY)x=venlist(st,N,x);
  Lst*r=ln();
  Z i=0;
  Lst*t=xa;
  WH(t){lp(r,vtake(st,N,Vnn(i),x));
    t=t->next;
    i++;}
  lp(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);
  Lst*r=ln();
  Z i=0;
  Lst*t=xa;
  WH(t){lp(r,vdrop(st,N,Vnn(i),x));
    t=t->next;
    i++;}
  lp(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=Vshow(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||le(ya)||!ya->next)R st->udf;R apD(st,x,ya->value,ya->next->value);}
Vt*vshape(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R st->unit;
  if(!Aap(xa))R venlist(st,N,vcount(st,N,x));
  if(!xa->next)R venlist(st,N,vshape(st,N,xa->value));R venpair(st,N,vcount(st,N,x),vcount(st,N,xa->value));}
Vt*vreshape(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  elif(le(ya))R y;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R st->unit;
  Lst*r;
  if(!xa->next){Vt*a=xa->value;
    if(a->tag!=NUM)R st->udf;
    Z k=fabs(a->val.number);
    Lst*t=ln();
    flatten(y,t);
    r=ln();
    WH(k){lp(r,t->value);
      if(t->next)t=t->next;
      k--;}}elif(xa->next){Vt*a=xa->value;
    if(a->tag!=NUM)R st->udf;
    Vt*b=xa->next->value;
    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);
    Lst*t=ya;
    r=ln();
    WH(k--){Lst*rw=ln();
      for(Z i=0;i<l;i++){lp(rw,t->value);
        t=t->next;}
      lp(r,Vna(rw));}}else R st->udf;R Vna(r);}
Vt*vrepr(St*st,vt*self,Vt*x){S s=Vshow(x);
  Lst*r=ln();
  for(Z i=0;i<strlen(s);i++)lp(r,Vnc(s[i]));
  FR(s);R Vna(r);}
S format(S template,Lst*replaces){Bt*text=Bnew();
  B skip=F;
  Z ri=0;
  Z tl=strlen(template);
  Z rl=ll(replaces);
  for(Z i=0;i<tl;i++){C c=template[i];
    if(skip){Bappend(text,c);
      skip=F;CN;}
    if(c=='_'){S s=Vshow(li(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=li(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(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  S fmt=Vshow(y);
  S s=format(fmt,xa);
  FR(fmt);
  Lst*r=ln();
  WH(*s)lp(r,Vnc(*s++));R Vna(r);}
Vt*vinsert(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY)y=venlist(st,N,y);
  Lst*r=ln();
  Lst*t=ya;
  WH(t){lp(r,t->value);
    if(t->next)lp(r,x);
    t=t->next;}
  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&&is_bad_num(xn))R st->udf;
    if(yt==NUM&&is_bad_num(yn))R st->udf;
    SZ s=Vnum(x);
    SZ e=Vnum(y);
    if(s==e)R venlist(st,N,x);
    Lst*r=ln();
    if(s>e)for(SZ i=s;i>=e;i--){if(xt==CHAR||yt==CHAR)lp(r,Vnc(i));
        else lp(r,Vnn(i));}
    else for(SZ i=s;i<=e;i++){if(xt==CHAR||yt==CHAR)lp(r,Vnc(i));
        else lp(r,Vnn(i));}
    R Vna(r);}
  R _NAN;}
Vt*vdeal(St*st,vt*self,Vt*x){if(xt!=ARRAY)R x;
  Lst*t=xa;
  if(le(t))R st->udf;
  Z i=rand()%ll(t);R li(t,i);}
Vt*vroll(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM){Lst*r=ln();
    Z k=fabs(xn);
    Z d=fabs(yn);
    for(Z i=0;i<k;i++)lp(r,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;
        Lst*r=ln();
        WH(*s)lp(r,Vnc(*s++));R Vna(r);}BR;
    CS NUM:if(yt==CHAR)R Vnn(y->val._char);
      elif(yt==ARRAY&&Cap(ya)){Bt*buf=Bnew();
        Lst*t=ya;
        WH(t){Bappend(buf,((Vt*)t->value)->val._char);
          t=t->next;}
        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=Vshow(x);
  fprintf(stdout,"%s",s);
  FR(s);R st->nil;}
Vt*vprintln(St*st,vt*self,Vt*x){S s=Vshow(x);
  fprintf(stdout,"%s\n",s);
  FR(s);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);
    Lst*r=ln();
    for(Z i=0;i<size;i++)lp(r,Vnc(s[i]));
    FR(s);R Vna(r);}
  elif(x==NUMS[1]){C line[512];
    if(!fgets(line,SO(line),stdin))R st->udf;
    Lst*r=ln();
    for(Z i=0;i<strlen(line);i++)lp(r,Vnc(line[i]));R Vna(r);}
  S path=Vshow(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);
  if(!buf)R st->udf;
  size=fread(buf,SO(unsigned char),size,fd);
  fclose(fd);
  FR(path);
  Lst*r=ln();
  for(Z i=0;i<size;i++)lp(r,Vnc(buf[i]));
  FR(buf);R Vna(r);}
Vt*vwrite(St*st,vt*self,Vt*x,Vt*y){if(xt!=ARRAY)x=venlist(st,N,x);
  S path=Vshow(y);
  FILE*fd=fopen(path,"wb");
  if(!fd){FR(path);R NNUMS[0];}
  Z k=0;
  Lst*t=xa;
  WH(t){UC c;
    Vt*v=t->value;
    if(v->tag==NUM)c=fabs(vn);
    elif(v->tag==CHAR)c=v->val._char;
    else BR;
    fputc(c,fd);
    t=t->next;k++;}
  fclose(fd);
  FR(path);R Vnn(k);}
Vt*vsystem(St*st,vt*self,Vt*x){S cmd=Vshow(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;
      if(!buffer)buffer=ma(Ballocated);
      else buffer=mrea(buffer,Ballocated);     
      if(!buffer){FR(cmd);
        pclose(pd);R st->udf;}}    
    for(Z i=0;i<bytes_received;i++)buffer[head+i]=chunk[i];
    if(feof(pd))BR;}
  pclose(pd);
  FR(cmd);
  Lst*r=ln();
  for(Z i=0;i<Bsize;i++)lp(r,Vnc(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(I*pipe){close(pipe[0]);
  close(pipe[1]);}
static I _do_popen2(files_chain_t*link,const S command){I child_in[2];
  I child_out[2];
  if(0!=pipe(child_in))R -1;
  if(0!=pipe(child_out)){_cleanup_pipe(child_in);R -1;}
  pid_t cpid=link->pid=fork();
  if(0>cpid){_cleanup_pipe(child_in);
    _cleanup_pipe(child_out);R -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(const S 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)R -1;
  if(0>fclose(fp->out)){free((files_chain_t*)fp);R -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)R -1;R status;}
Vt*vsystem2(St*st,vt*self,Vt*x,Vt*y){S cmd=Vshow(y);
  files_t*pd;
  pd=popen2(cmd);
  if(pd==N){FR(cmd);R st->udf;}
  Lst*t=xa;
  WH(t){UC c;
    Vt*v=t->value;
    if(v->tag==NUM)c=fabs(vn);
    elif(v->tag==CHAR)c=v->val._char;
    else BR;
    fputc(c,pd->in);
    t=t->next;}
  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;
      if(!buffer)buffer=ma(Ballocated);
      else buffer=mrea(buffer,Ballocated);     
      if(!buffer){FR(cmd);
        pclose2(pd);R st->udf;}}    
    for(Z i=0;i<bytes_received;i++)buffer[head+i]=chunk[i];
    if(feof(pd->out))BR;}
  pclose2(pd);
  FR(cmd);
  Lst*r=ln();
  for(Z i=0;i<Bsize;i++)lp(r,Vnc(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;}
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;}
Lst*prime_factors(D n){Lst*factors=ln();
  D divisor=2;
  WH(n>=2){if(fmod(n,divisor)==0){lp(factors,Vnn(divisor));
      n/=divisor;}else divisor++;}
  R factors;}
Vt*vfactors(St*st,vt*self,Vt*x){if(xt==NUM&&!is_bad_num(xn))R Vna(prime_factors(xn));R st->udf;}
Vt*vcombine(St*st,vt*self,Vt*x,Vt*y){if(xt==NUM&&yt==NUM&&!is_bad_num(xn)&&!is_bad_num(yn)){Vt*n=venpair(st,N,x,y);R vunbase(st,N,NUMS[10],n);}
  R _NAN;}
Vt*Srun(St*st,S program);
Vt*veval(St*st,vt*self,Vt*x){S s=Vshow(x);
  jmp_buf*lb=guard();
  if(setjmp(*lb)){unguard();
    FR(s);R st->udf;}
  Vt*v=Srun(st,s);
  FR(s);
  unguard();R v;}
Vt*vimport(St*st,vt*self,Vt*x){S path=Vshow(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);
  if(!buf)R st->udf;
  size=fread(buf,SO(unsigned char),size,fd);
  fclose(fd);
  FR(path);
  Vt*v=Srun(st,(S)buf);
  FR(buf);R v;}
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(":",0,0,0,udf1,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("<",0,0,X,gradedown,nudge_left),DEFVERB(">",X,X,X,succ,greater),DEFVERBD(">",X,X,X,ceil,greatereq),DEFVERBC(">",0,0,X,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,0,0,round,rotate),DEFVERBC("|",0,X,0,depth,windows),DEFVERB("@",X,0,X,abs,at),DEFVERBD("@",0,0,0,shuffle,member),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),DEFVERB("]",0,0,0,same,right),DEFVERBD("`",0,0,0,symbol,apply1),DEFVERBC("`",0,0,0,square,apply2),DEFVERB("$",0,0,0,shape,reshape),DEFVERBD("$",0,0,0,repr,format),DEFVERBD("p",0,0,0,print,udf2),DEFVERBD("P",0,0,0,println,udf2),DEFVERBD("f",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,udf2)};
Vt*_advfold_m(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R x;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*t=xa->value;
  Lst*tx=xa->next;
  WH(tx){t=tgth(st,v,t,tx->value,0,0,v->rank[1],v->rank[2]);
    tx=tx->next;}
  R t;}
Vt*_advfold_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||le(ya))R y;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Vt*t=x;
  Lst*ty=ya;
  WH(ty){t=tgth(st,v,t,ty->value,0,0,v->rank[1],v->rank[2]);
    ty=ty->next;}
  R t;}
Vt*_advscan_m(St*st,vt*self,Vt*x){if(xt!=ARRAY||le(xa))R x;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Vt*t=xa->value;
  Lst*tx=xa->next;
  lp(r,t);
  WH(tx){t=tgth(st,v,t,tx->value,0,0,v->rank[1],v->rank[2]);
    lp(r,t);
    tx=tx->next;}
  R Vna(r);}
Vt*_advscan_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||le(ya))R y;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Vt*t=x;
  Lst*ty=ya;
  lp(r,t);
  WH(ty){t=tgth(st,v,t,ty->value,0,0,v->rank[1],v->rank[2]);
    lp(r,t);
    ty=ty->next;}
  R Vna(r);}
Vt*_adveach_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  if(xt!=ARRAY)R eR(st,v,x,0,1);
  if(le(xa))R x;R eR(st,v,x,0,1);}
Vt*_adveach_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->value;
  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);
  Lst*r=ln();
  Lst*tx=xa;
  Lst*ty=ya;
  WH(tx&&ty){lp(r,tgth(st,v,tx->value,ty->value,0,0,v->rank[1],v->rank[2]));
    tx=tx->next;
    ty=ty->next;}
  R Vna(r);}
Vt*_advconverge_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  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->value;
  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(le(ya))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->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Vt*t;
  lp(r,x);
  LOOP{t=x;
    x=eR(st,v,x,0,v->rank[0]);
    if(Veq(x,t))BR;
    lp(r,x);}
  R Vna(r);}
Vt*_advconverges_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->value;
  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(le(ya))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||le(xa)||!xa->next)R x;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Lst*p=xa;
  Lst*t=xa->next;
  WH(t){lp(r,tgth(st,v,t->value,p->value,0,0,v->rank[1],v->rank[2]));
    p=t;
    t=t->next;}
  R Vna(r);}
Vt*_adveachprior_d(St*st,vt*self,Vt*x,Vt*y){if(yt!=ARRAY||le(ya))R y;
  Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Lst*p=N;
  Lst*t=ya;
  WH(t){lp(r,tgth(st,v,t->value,!p?x:p->value,0,0,v->rank[1],v->rank[2]));
    p=t;
    t=t->next;}
  R Vna(r);}
Vt*_advreflex_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  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->value;
  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->value;
  if(v->tag!=ARRAY)v=venlist(st,N,v);
  if(yt!=ARRAY)y=venlist(st,N,y);
  Lst*r=lc(ya);
  Z i=0;
  Z l=ll(xa);
  Lst*t=v->val.array;
  WH(t){Vt*n=t->value;
    if(n->tag!=NUM)BR;
    ls(r,n->val.number,li(xa,i<l?i:l-1));
    t=t->next;
    i++;}
  R Vna(r);}
Vt*_advfilter_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  vt*v=_v->val.verb;
  Lst*r=ln();
  Lst*t=xa;
  WH(t){Vt*b=eR(st,v,t->value,0,v->rank[0]);
    if(VTp(b))lp(r,t->value);
    t=t->next;}
  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->value;
  if(v->tag!=VERB)R st->udf;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R x;
  Lst*r=ln();
  Lst*t=xa;
  Lst*p=ln();
  WH(t){Vt*b=apM(st,v,t->value);
    if(VTp(b)){lp(r,Vna(p));
      p=ln();}else lp(p,t->value);
    t=t->next;}
  lp(r,Vna(p));R Vna(r);}
Vt*_advspan_d(St*st,vt*self,Vt*x,Vt*y){R _adveach_m(st,self,vwindows(st,N,x,y));}
Vt*_advinverse_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  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->value;
  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);}
Vt*_advlaminate_m(St*st,vt*self,Vt*x){Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  if(xt!=ARRAY)x=venlist(st,N,x);
  elif(le(xa))R st->udf;
  Vt*r=xa->value;
  Lst*t=xa;
  WH(t){r=apD(st,_v,r,t->value);
    t=t->next;}
  R r;}
Vt*_advlaminate_d(St*st,vt*self,Vt*x,Vt*y){Vt*_v=self->bonds->value;
  if(_v->tag!=VERB)R st->udf;
  if(yt!=ARRAY)y=venlist(st,N,y);
  elif(le(ya))R st->udf;
  Vt*r=x;
  Lst*t=ya;
  WH(t){r=apD(st,_v,r,t->value);
    t=t->next;}
  R r;}
#define ADVERB(__name,__symb)\
  vt*adv##__name(St*st,Vt*v){\
    vt*nv=vnew();\
    nv->bonds=ln();\
    lp(nv->bonds,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,"-:");
ADVERB(laminate,"@:");
advt ADVERBS[]={{"/",advfold,N},  {"/.",advconverge,N},{"\\",advscan,N}, {"\\.",advconverges,N},{"\"",adveach,N}, {"\".",adveachprior,N},{";.",advreflex,N},{"`",advamend,N},{"&.",advfilter,N},{"/:",advspan,N},{"-:",advinverse,N},{"@:",advlaminate,N}};
Vt*_cnjbond_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->value;
  Vt*v2=self->bonds->next->value;
  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->nil;}
Vt*_cnjbond_d(St*st,vt*self,Vt*x,Vt*y){Vt*v1=self->bonds->value;
  Vt*v2=self->bonds->next->value;
  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->nil;}
Vt*_cnjpick_m(St*st,vt*self,Vt*x){Vt*v1=self->bonds->value;
  Vt*v2=self->bonds->next->value;
  if(v1->tag!=VERB||v2->tag!=ARRAY)R st->nil;
  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->value;
  Vt*v2=self->bonds->next->value;
  if(v1->tag!=VERB||v2->tag!=ARRAY)R st->nil;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  if(v1->tag!=VERB||v2->tag!=NUM)R st->udf;
  UI rank =
      v2->val.number==INFINITY?UINT_MAX:fabs(v2->val.number);R tgth(st,v1->val.verb,x,y,0,0,rank,rank);}
Vt*_cnjmonaddyad_m(St*st,vt*self,Vt*x){Vt*v=self->bonds->value;
  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->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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->value;
  Vt*v2=self->bonds->next->value;
  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=ln();\
    lp(nv->bonds,x);\
    lp(nv->bonds,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(Lst*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;}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 li(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->value;
  if(xt!=VERB)R st->nil;R Vnv(av->adverb(st,x));}
Vt*_advwrapper_d(St*st,vt*self,Vt*x,Vt*y){advt*av=self->bonds->value;
  if(xt!=VERB)R st->nil;
  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=ln();
  lp(nv->bonds,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->value;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=ln();
  lp(nv->bonds,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;}
    node=PPexpr(parser);
    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_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{Lst*list=ln();
      for(Z i=0;i<strlen(tok->text);i++)lp(list,Vnc(tok->text[i]));
      node=Nnl(Vna(list));}BR;}
  if(!node)Perror(parser,"parse");
  Peat(parser);R node;}
Nt*PPa(Pt*parser,Nt*a,enum Tkt tag){Tkt*tok;
  if((tok=Plook(parser,0))&&tok->tag==tag){Lst*as=ln();
    lp(as,a->v);
    do{a=PPatom(parser);
      lp(as,a->v);}WH((tok=Plook(parser,0))&&tok->tag==tag);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 &&(n=PPa(parser,a,T_NAME)))R n;
  elif(a->tag==N_LITERAL&&a->v->tag==ARRAY &&Cap(a->v->val.array)&&(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);
    Lst*l=ln();
    lp(l,a);
    LOOP{a=flat?PPatom(parser):_PPnoun(parser);
      lp(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,B*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,B*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;
  Lst*ns=ln();
  WH(!Pstop(parser)){if(le(ns)&&(tmp=Plook(parser,0))&&tmp->tag==T_PUNCT&&strcmp(tmp->text,":")==0 &&(Plook(parser,1))){Peat(parser);R Nn1(N_FUN,PPexpr(parser));}
    Nt*n=PPnoun(parser,F);
    if(le(ns)&&n->tag==N_LITERAL&&n->v->tag==SYM &&(tmp=Plook(parser,0))&&tmp->tag==T_PUNCT &&strcmp(tmp->text,":")==0){Peat(parser);R Nn2(N_BIND,n,PPexpr(parser));}
    LOOP{B flag=F;
      n=PPadv(parser,n,&flag);
      n=PPcnj(parser,n,&flag);
      if(!flag)BR;}
    lp(ns,n);}
  Z len;
  Nt*l,*m,*r;
  LOOP{len=ll(ns);
    if(len<2)BR;
    if(len>=3&&is_apply(li(ns,-2))||is_obverse(li(ns,-2))){r=lP(ns);
      m=lP(ns);
      l=lP(ns);
      lp(ns,Nn3(N_DYAD,m,l,r));}elif(len>=3&&!Nisv(parser,li(ns,-1))&&Nisv(parser,li(ns,-2))&&!Nisv(parser,li(ns,-3))){r=lP(ns);
      m=lP(ns);
      l=lP(ns);
      lp(ns,Nn3(N_DYAD,m,l,r));}elif(len>=3&&Nisv(parser,li(ns,-1))&&Nisv(parser,li(ns,-2))&&Nisv(parser,li(ns,-3))){r=lP(ns);
      m=lP(ns);
      l=lP(ns);
      lp(ns,Nn3(N_FORK,l,m,r));}elif(len>=3&&Nisv(parser,li(ns,-1))&&Nisv(parser,li(ns,-2))&&!Nisv(parser,li(ns,-3))){r=lP(ns);
      m=lP(ns);
      l=lP(ns);
      lp(ns,Nn3(N_OVER,l,m,r));}elif(len>=2&&is_apply(li(ns,-1))){r=lP(ns);
      l=lP(ns);
      lp(ns,Nn2(N_BOND,r,l));}elif(len>=2&&!Nisv(parser,li(ns,-1))&&Nisv(parser,li(ns,-2))){r=lP(ns);
      l=lP(ns);
      lp(ns,Nn2(N_MONAD,l,r));}elif(len>=2&&Nisv(parser,li(ns,-1))&&Nisv(parser,li(ns,-2))){r=lP(ns);
      l=lP(ns);
      lp(ns,Nn2(N_HOOK,l,r));}elif(len>=2&&Nisv(parser,li(ns,-1))&&!Nisv(parser,li(ns,-2))){r=lP(ns);
      l=lP(ns);
      lp(ns,Nn2(N_BOND,r,l));}elif(len>=3){r=lP(ns);
      m=lP(ns);
      l=lP(ns);
      lp(ns,Nn3(N_INDEX2,m,l,r));}elif(len>=2){r=lP(ns);
      l=lP(ns);
      lp(ns,Nn2(N_INDEX1,l,r));}}
  R ns->value;}
Nt*Pparse(Pt*parser,Lt*lexer){parser->lexer=lexer;
  parser->pos=0;
  parser->end=ll(parser->lexer->tokens);
  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);
  Lst*t=lexer->tokens;
  if(t->value)WH(t){Lst*tmp=t->next;
      Tkt*tok=t->value;
      if(tok->text)FR(tok->text);
      FR(tok);
      FR(t);
      t=tmp;}
  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 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 reciprocal    1 / x" "\n"\
"%  dyadic  divide        divide numbers" "\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 exp           e^x" "\n"\
"^  dyadic  power         raise number to a power" "\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"\
"~: 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"\
">  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"\
",  monadic enlist        put x into 1-elt array" "\n"\
",  dyadic  join          concat x and y" "\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"\
"_: monadic bits          _:5 is 1 0 1" "\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"\
"@  monadic abs           |x|" "\n"\
"@  dyadic  at            pick elts from x by indices from y" "\n"\
"{  monadic head          all elts of x except last, same as -1_" "\n"\
"{  dyadic  bin           bin search, e.g. 1 3 5 7 9{8 9 0 yields 3 4 -1" "\n"\
"}  monadic behead        all elts of x except first, same as 1_" "\n"\
"[  dyadic  left          yield x" "\n"
"]  monadic same          yield x (i.e. identity)" "\n"
"]  dyadic  right         yield y (i.e. right argument)" "\n"
"$  monadic shape         yield shape of x" "\n"
"$  dyadic  reshape       reshape y to shape x" "\n"
"";
cS V2HELP =\
"p. monadic print         print x" "\n"\
"P. monadic println       print x and a \\n" "\n"\
"f. monadic selfref1      monadic reference to current function or rhs of bind" "\n"\
"f. dyadic  selfref2      dyadic reference to current function or rhs of bind" "\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"\
"i. monadic import        load and eval source file" "\n"\
"y. monadic system        exec system command (yields output)" "\n"\
"y. dyadic  system2       exec system command with input" "\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"\
"\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"\
"\n"\
"f/       fold          +/1 2 3 yields 6" "\n"\
"xf/      foldwith      1+/1 2 3 yields 7" "\n"\
"\n"\
"f\\       scan          +/1 2 3 yields 1 3 6" "\n"\
"xf\\      scanwith      1+\\1 2 3 yields 1 2 4 7" "\n"\
"\n"\
"f/.      converge      _;1/.1 2 3 yields ()" "\n"\
"";
cS CHELP =\
"f;g      bond     */;!.5 yields 120, +;1 5 yields 6, 5;- 1 yields 4" "\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  inverse  (~fx)~f~fx" "\n"\
"f^:Fx  under    ~FfFx" "\n"\
"xf^:Fx under    ~F(Fx)f(Fx)" "\n"\
"";
cS SHELP =\
"/ comment" "\n"\
"5+5 / also comment" "\n"\
"5+5/not comment (no whitespace before /)" "\n\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"\
"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"\
"()                        / 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";
I main(I argc,S*argv){GC_INIT();
  GC_enable_incremental();
  guards=ln();
  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=ln();
  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;
  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,"[",Srun(st,"*/")->val.verb);
  Tset(Inverses,"!",Srun(st,">|/")->val.verb);
  Tset(Inverses,"!.",Srun(st,"|/")->val.verb);
  Tset(Inverses,"]@>:",Srun(st,"]@<:")->val.verb);
  Tset(Inverses,"]@<:",Srun(st,"]@>:")->val.verb);
  Lst*args=ln();
  for(I i=1;i<argc;i++){Lst*arg=ln();
    S s=argv[i];
    WH(*s)lp(arg,CHARS[*s++]);
    lp(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;}
  LOOP{Bt*buffer;
    C line[256];
    buffer=Bnew();
    if(Iin)putc('\t',stdout);
    if(!fgets(line,SO(line),stdin))BR;
    if(Iin){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(Iin)putc('\t',stdout);
      if(!fgets(line,SO(line),stdin))R 0;}
    BappendS(buffer,line);
    s=Bread(buffer);
    Vt*v=Srun(st,s);
    FR(s);s=N;
    if(v->tag!=NIL){Tset(st->env,"it",v);
      S s=Vshow(v);
      fputs(s,stdout);
      if(Iin)putc('\n',stdout);}}}