txlyre
/
avram


			
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129
							<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html401/loose.dtd">
<html>
<!-- Created on December 10, 2012 by texi2html 1.82
texi2html was written by: 
            Lionel Cons <[email protected]> (original author)
            Karl Berry  <[email protected]>
            Olaf Bachmann <[email protected]>
            and many others.
Maintained by: Many creative people.
Send bugs and suggestions to <[email protected]>
-->
<head>
<title>avram - a virtual machine code interpreter: 2.6.4 Output From Interactive Applications</title>

<meta name="description" content="avram - a virtual machine code interpreter: 2.6.4 Output From Interactive Applications">
<meta name="keywords" content="avram - a virtual machine code interpreter: 2.6.4 Output From Interactive Applications">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="texi2html 1.82">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.smallquotation {font-size: smaller}
pre.display {font-family: serif}
pre.format {font-family: serif}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: serif; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: serif; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.roman {font-family:serif; font-weight:normal;}
span.sansserif {font-family:sans-serif; font-weight:normal;}
ul.toc {list-style: none}
-->
</style>


</head>

<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">

<a name="Output-From-Interactive-Applications"></a>
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="Output-From-Non_002dinteractive-Applications.html#Output-From-Non_002dinteractive-Applications" title="Previous section in reading order"> &lt; </a>]</td>
<td valign="middle" align="left">[<a href="Line-Oriented-Interaction.html#Line-Oriented-Interaction" title="Next section in reading order"> &gt; </a>]</td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left">[<a href="Virtual-Machine-Specification.html#Virtual-Machine-Specification" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
<td valign="middle" align="left">[<a href="Parameter-Mode-Interface.html#Parameter-Mode-Interface" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="Library-Reference.html#Library-Reference" title="Next chapter"> &gt;&gt; </a>]</td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left">[<a href="avram.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="avram_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Function-Index.html#Function-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="avram_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<hr size="1">
<a name="Output-From-Interactive-Applications-1"></a>
<h3 class="subsection">2.6.4 Output From Interactive Applications</h3>

<a name="index-interactive-command-line-option-2"></a>
<a name="index-step-command-line-option-2"></a>
<p>Parameter mode applications invoked with either of the
&lsquo;<samp>--interactive</samp>&rsquo; or &lsquo;<samp>--step</samp>&rsquo; options are
required to take the data structure described in <a href="Input-Data-Structure.html#Input-Data-Structure">Input Data Structure</a> as an
argument but to return the virtual code for a function that will observe
<a name="index-shell-2"></a>
a certain protocol allowing shell commands to be executed on its
behalf. The intent is that the virtual code file doesn&rsquo;t contain the
real application <em>per se</em>, but only something that builds the real
one on the fly using configuration information from the input files and
command line options.
</p>
<p>The format of the result returned by an interactive application, being a
virtual code application itself, requires a full exposition of the
virtual machine code semantics. This subject is deferred to <a href="Virtual-Code-Semantics.html#Virtual-Code-Semantics">Virtual Code Semantics</a>.
The remainder of this section describes the protocol followed by the
function returned by the interactive application rather than the
application itself.
</p>
<p>Similarly to the case of a byte transducer described in <a href="Byte-Transducers.html#Byte-Transducers">Byte Transducers</a>,
the basic pattern of interaction between <code>avram</code> and the function
is a cycle of invocations. In general terms, the function is applied to
a <code>nil</code> argument initially, and expected to return an initial state
and initial output. Thereafter, the function is applied to a pair of the
state returned on the previous iteration, and the next installment of
input. The function returns further output and a new state, and the
cycle continues until the function returns a value of <code>nil</code>, at
which time the computation terminates.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top"><a href="Line-Oriented-Interaction.html#Line-Oriented-Interaction">2.6.4.1 Line Oriented Interaction</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">   
</td></tr>
<tr><td align="left" valign="top"><a href="Character-Oriented-Interaction.html#Character-Oriented-Interaction">2.6.4.2 Character Oriented Interaction</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">  
</td></tr>
<tr><td align="left" valign="top"><a href="Mixed-Modes-of-Interaction.html#Mixed-Modes-of-Interaction">2.6.4.3 Mixed Modes of Interaction</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">  
</td></tr>
</table>

<hr size="1">
<table cellpadding="1" cellspacing="1" border="0">
<tr><td valign="middle" align="left">[<a href="Output-From-Non_002dinteractive-Applications.html#Output-From-Non_002dinteractive-Applications" title="Previous section in reading order"> &lt; </a>]</td>
<td valign="middle" align="left">[<a href="Line-Oriented-Interaction.html#Line-Oriented-Interaction" title="Next section in reading order"> &gt; </a>]</td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left">[<a href="Virtual-Machine-Specification.html#Virtual-Machine-Specification" title="Beginning of this chapter or previous chapter"> &lt;&lt; </a>]</td>
<td valign="middle" align="left">[<a href="Parameter-Mode-Interface.html#Parameter-Mode-Interface" title="Up section"> Up </a>]</td>
<td valign="middle" align="left">[<a href="Library-Reference.html#Library-Reference" title="Next chapter"> &gt;&gt; </a>]</td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left"> &nbsp; </td>
<td valign="middle" align="left">[<a href="avram.html#Top" title="Cover (top) of document">Top</a>]</td>
<td valign="middle" align="left">[<a href="avram_toc.html#SEC_Contents" title="Table of contents">Contents</a>]</td>
<td valign="middle" align="left">[<a href="Function-Index.html#Function-Index" title="Index">Index</a>]</td>
<td valign="middle" align="left">[<a href="avram_abt.html#SEC_About" title="About (help)"> ? </a>]</td>
</tr></table>
<p>
 <font size="-1">
  This document was generated on <i>December 10, 2012</i> using <a href="http://www.nongnu.org/texi2html/"><i>texi2html 1.82</i></a>.
 </font>
 <br>

</p>
</body>
</html>