sforman
/
Thun
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
Thun/docs/sphinx_docs/_build/html/stack.html

274 lines
17 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Stack or Quote or Sequence or List… &#8212; Thun 0.2.0 documentation</title>
<link rel="stylesheet" href="_static/alabaster.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<script type="text/javascript" src="_static/documentation_options.js"></script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="next" title="Parsing Text into Joy Expressions" href="parser.html" />
<link rel="prev" title="Joy Interpreter" href="joy.html" />
<link rel="stylesheet" href="_static/custom.css" type="text/css" />
<meta name="viewport" content="width=device-width, initial-scale=0.9, maximum-scale=0.9" />
</head><body>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="stack-or-quote-or-sequence-or-list">
<h1>Stack or Quote or Sequence or List…<a class="headerlink" href="#stack-or-quote-or-sequence-or-list" title="Permalink to this headline"></a></h1>
<div class="section" id="module-joy.utils.stack">
<span id="joy-utils-stack"></span><h2><code class="docutils literal notranslate"><span class="pre">joy.utils.stack</span></code><a class="headerlink" href="#module-joy.utils.stack" title="Permalink to this headline"></a></h2>
<p>When talking about Joy we use the terms “stack”, “quote”, “sequence”,
“list”, and others to mean the same thing: a simple linear datatype that
permits certain operations such as iterating and pushing and popping
values from (at least) one end.</p>
<p>There is no “Stack” Python class, instead we use the <a class="reference external" href="https://en.wikipedia.org/wiki/Cons#Lists">cons list</a>, a
venerable two-tuple recursive sequence datastructure, where the
empty tuple <code class="docutils literal notranslate"><span class="pre">()</span></code> is the empty stack and <code class="docutils literal notranslate"><span class="pre">(head,</span> <span class="pre">rest)</span></code> gives the recursive
form of a stack with one or more items on it:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">stack</span> <span class="p">:</span><span class="o">=</span> <span class="p">()</span> <span class="o">|</span> <span class="p">(</span><span class="n">item</span><span class="p">,</span> <span class="n">stack</span><span class="p">)</span>
</pre></div>
</div>
<p>Putting some numbers onto a stack:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">()</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="p">())</span>
<span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="p">()))</span>
<span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="p">())))</span>
<span class="o">...</span>
</pre></div>
</div>
<p>Python has very nice “tuple packing and unpacking” in its syntax which
means we can directly “unpack” the expected arguments to a Joy function.</p>
<p>For example:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">dup</span><span class="p">((</span><span class="n">head</span><span class="p">,</span> <span class="n">tail</span><span class="p">)):</span>
<span class="k">return</span> <span class="n">head</span><span class="p">,</span> <span class="p">(</span><span class="n">head</span><span class="p">,</span> <span class="n">tail</span><span class="p">)</span>
</pre></div>
</div>
<p>We replace the argument “stack” by the expected structure of the stack,
in this case “(head, tail)”, and Python takes care of unpacking the
incoming tuple and assigning values to the names. (Note that Python
syntax doesn’t require parentheses around tuples used in expressions
where they would be redundant.)</p>
<p>Unfortunately, the Sphinx documentation generator, which is used to generate this
web page, doesn’t handle tuples in the function parameters. And in Python 3, this
syntax was removed entirely. Instead you would have to write:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">dup</span><span class="p">(</span><span class="n">stack</span><span class="p">):</span>
<span class="n">head</span><span class="p">,</span> <span class="n">tail</span> <span class="o">=</span> <span class="n">stack</span>
<span class="k">return</span> <span class="n">head</span><span class="p">,</span> <span class="p">(</span><span class="n">head</span><span class="p">,</span> <span class="n">tail</span><span class="p">)</span>
</pre></div>
</div>
<p>We have two very simple functions, one to build up a stack from a Python
iterable and another to iterate through a stack and yield its items
one-by-one in order. There are also two functions to generate string representations
of stacks. They only differ in that one prints the terms in stack from left-to-right while the other prints from right-to-left. In both functions <em>internal stacks</em> are
printed left-to-right. These functions are written to support <a class="reference internal" href="pretty.html"><span class="doc">Tracing Joy Execution</span></a>.</p>
<dl class="function">
<dt id="joy.utils.stack.expression_to_string">
<code class="descclassname">joy.utils.stack.</code><code class="descname">expression_to_string</code><span class="sig-paren">(</span><em>expression</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#expression_to_string"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.expression_to_string" title="Permalink to this definition"></a></dt>
<dd><p>Return a “pretty print” string for a expression.</p>
<p>The items are written left-to-right:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="n">top</span><span class="p">,</span> <span class="p">(</span><span class="n">second</span><span class="p">,</span> <span class="o">...</span><span class="p">))</span> <span class="o">-&gt;</span> <span class="s1">&#39;top second ...&#39;</span>
</pre></div>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>expression</strong> (<em>stack</em>) – A stack.</td>
</tr>
<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">str</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="joy.utils.stack.iter_stack">
<code class="descclassname">joy.utils.stack.</code><code class="descname">iter_stack</code><span class="sig-paren">(</span><em>stack</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#iter_stack"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.iter_stack" title="Permalink to this definition"></a></dt>
<dd><p>Iterate through the items on the stack.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>stack</strong> (<em>stack</em>) – A stack.</td>
</tr>
<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">iterator</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="joy.utils.stack.list_to_stack">
<code class="descclassname">joy.utils.stack.</code><code class="descname">list_to_stack</code><span class="sig-paren">(</span><em>el</em>, <em>stack=()</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#list_to_stack"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.list_to_stack" title="Permalink to this definition"></a></dt>
<dd><p>Convert a Python list (or other sequence) to a Joy stack:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">]</span> <span class="o">-&gt;</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="p">())))</span>
</pre></div>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>el</strong> (<em>list</em>) – A Python list or other sequence (iterators and generators
won’t work because <code class="docutils literal notranslate"><span class="pre">reverse()</span></code> is called on <code class="docutils literal notranslate"><span class="pre">el</span></code>.)</li>
<li><strong>stack</strong> (<em>stack</em>) – A stack, optional, defaults to the empty stack.</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">stack</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="joy.utils.stack.pick">
<code class="descclassname">joy.utils.stack.</code><code class="descname">pick</code><span class="sig-paren">(</span><em>s</em>, <em>n</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#pick"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.pick" title="Permalink to this definition"></a></dt>
<dd><p>Return the nth item on the stack.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>s</strong> (<em>stack</em>) – A stack.</li>
<li><strong>n</strong> (<em>int</em>) – An index into the stack.</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Raises:</th><td class="field-body"><ul class="first simple">
<li><strong>ValueError</strong> – if <code class="docutils literal notranslate"><span class="pre">n</span></code> is less than zero.</li>
<li><strong>IndexError</strong> – if <code class="docutils literal notranslate"><span class="pre">n</span></code> is equal to or greater than the length of <code class="docutils literal notranslate"><span class="pre">s</span></code>.</li>
</ul>
</td>
</tr>
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">whatever</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="joy.utils.stack.pushback">
<code class="descclassname">joy.utils.stack.</code><code class="descname">pushback</code><span class="sig-paren">(</span><em>quote</em>, <em>expression</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#pushback"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.pushback" title="Permalink to this definition"></a></dt>
<dd><p>Concatinate quote onto expression.</p>
<p>In joy [1 2] [3 4] would become [1 2 3 4].</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>quote</strong> (<em>stack</em>) – A stack.</li>
<li><strong>expression</strong> (<em>stack</em>) – A stack.</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Raises:</th><td class="field-body"><p class="first"><strong>RuntimeError</strong> – if quote is larger than sys.getrecursionlimit().</p>
</td>
</tr>
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">stack</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="joy.utils.stack.stack_to_string">
<code class="descclassname">joy.utils.stack.</code><code class="descname">stack_to_string</code><span class="sig-paren">(</span><em>stack</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/joy/utils/stack.html#stack_to_string"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#joy.utils.stack.stack_to_string" title="Permalink to this definition"></a></dt>
<dd><p>Return a “pretty print” string for a stack.</p>
<p>The items are written right-to-left:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="n">top</span><span class="p">,</span> <span class="p">(</span><span class="n">second</span><span class="p">,</span> <span class="o">...</span><span class="p">))</span> <span class="o">-&gt;</span> <span class="s1">&#39;... second top&#39;</span>
</pre></div>
</div>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>stack</strong> (<em>stack</em>) – A stack.</td>
</tr>
<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">str</td>
</tr>
</tbody>
</table>
</dd></dl>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Stack or Quote or Sequence or List…</a><ul>
<li><a class="reference internal" href="#module-joy.utils.stack"><code class="docutils literal notranslate"><span class="pre">joy.utils.stack</span></code></a></li>
</ul>
</li>
</ul>
<div class="relations">
<h3>Related Topics</h3>
<ul>
<li><a href="index.html">Documentation overview</a><ul>
<li>Previous: <a href="joy.html" title="previous chapter">Joy Interpreter</a></li>
<li>Next: <a href="parser.html" title="next chapter">Parsing Text into Joy Expressions</a></li>
</ul></li>
</ul>
</div>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="_sources/stack.rst.txt"
rel="nofollow">Show Source</a></li>
</ul>
</div>
<div id="searchbox" style="display: none" role="search">
<h3>Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="search.html" method="get">
<input type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="footer" role="contentinfo">
<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">
<img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" />
</a>
<br />
<span xmlns:dct="http://purl.org/dc/terms/" property="dct:title">Thun Documentation</span> by <a xmlns:cc="http://creativecommons.org/ns#" href="https://joypy.osdn.io/" property="cc:attributionName" rel="cc:attributionURL">Simon Forman</a> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>.<br />Based on a work at <a xmlns:dct="http://purl.org/dc/terms/" href="https://osdn.net/projects/joypy/" rel="dct:source">https://osdn.net/projects/joypy/</a>.
Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.7.3.
</div>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink