📄 node376.html
字号:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>17.1.6.1 Emulation of compile()</title>
<META NAME="description" CONTENT="17.1.6.1 Emulation of compile()">
<META NAME="keywords" CONTENT="lib">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel="STYLESHEET" href="lib.css" tppabs="http://www.python.org/doc/current/lib/lib.css">
<LINK REL="next" HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html">
<LINK REL="previous" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">
<LINK REL="up" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">
<LINK REL="next" HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html">
</head>
<body>
<DIV CLASS="navigation"><table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td><A href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html"><img src="previous.gif" tppabs="http://www.python.org/doc/current/icons/previous.gif" border="0" height="32"
alt="Previous Page" width="32"></A></td>
<td><A href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html"><img src="up.gif" tppabs="http://www.python.org/doc/current/icons/up.gif" border="0" height="32"
alt="Up One Level" width="32"></A></td>
<td><A HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html"><img src="next.gif" tppabs="http://www.python.org/doc/current/icons/next.gif" border="0" height="32"
alt="Next Page" width="32"></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td><A href="contents.html" tppabs="http://www.python.org/doc/current/lib/contents.html"><img src="contents.gif" tppabs="http://www.python.org/doc/current/icons/contents.gif" border="0" height="32"
alt="Contents" width="32"></A></td>
<td><a href="modindex.html" tppabs="http://www.python.org/doc/current/lib/modindex.html" title="Module Index"><img src="modules.gif" tppabs="http://www.python.org/doc/current/icons/modules.gif" border="0" height="32"
alt="Module Index" width="32"></a></td>
<td><A href="genindex.html" tppabs="http://www.python.org/doc/current/lib/genindex.html"><img src="index.gif" tppabs="http://www.python.org/doc/current/icons/index.gif" border="0" height="32"
alt="Index" width="32"></A></td>
</tr></table>
<b class="navlabel">Previous:</b> <a class="sectref" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">17.1.6 Examples</A>
<b class="navlabel">Up:</b> <a class="sectref" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">17.1.6 Examples</A>
<b class="navlabel">Next:</b> <a class="sectref" HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html">17.1.6.2 Information Discovery</A>
<br><hr></DIV>
<!--End of Navigation Panel-->
<H3><A NAME="SECTION0019161000000000000000">
17.1.6.1 Emulation of <tt class="function">compile()</tt></A>
</H3>
<P>
While many useful operations may take place between parsing and
bytecode generation, the simplest operation is to do nothing. For
this purpose, using the <tt class="module">parser</tt> module to produce an
intermediate data structure is equivalent to the code
<P>
<dl><dd><pre class="verbatim">
>>> code = compile('a + 5', 'file.py', 'eval')
>>> a = 5
>>> eval(code)
10
</pre></dl>
<P>
The equivalent operation using the <tt class="module">parser</tt> module is somewhat
longer, and allows the intermediate internal parse tree to be retained
as an AST object:
<P>
<dl><dd><pre class="verbatim">
>>> import parser
>>> ast = parser.expr('a + 5')
>>> code = ast.compile('file.py')
>>> a = 5
>>> eval(code)
10
</pre></dl>
<P>
An application which needs both AST and code objects can package this
code into readily available functions:
<P>
<dl><dd><pre class="verbatim">
import parser
def load_suite(source_string):
ast = parser.suite(source_string)
return ast, ast.compile()
def load_expression(source_string):
ast = parser.expr(source_string)
return ast, ast.compile()
</pre></dl>
<P>
<DIV CLASS="navigation"><p><hr><table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td><A href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html"><img src="previous.gif" tppabs="http://www.python.org/doc/current/icons/previous.gif" border="0" height="32"
alt="Previous Page" width="32"></A></td>
<td><A href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html"><img src="up.gif" tppabs="http://www.python.org/doc/current/icons/up.gif" border="0" height="32"
alt="Up One Level" width="32"></A></td>
<td><A HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html"><img src="next.gif" tppabs="http://www.python.org/doc/current/icons/next.gif" border="0" height="32"
alt="Next Page" width="32"></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td><A href="contents.html" tppabs="http://www.python.org/doc/current/lib/contents.html"><img src="contents.gif" tppabs="http://www.python.org/doc/current/icons/contents.gif" border="0" height="32"
alt="Contents" width="32"></A></td>
<td><a href="modindex.html" tppabs="http://www.python.org/doc/current/lib/modindex.html" title="Module Index"><img src="modules.gif" tppabs="http://www.python.org/doc/current/icons/modules.gif" border="0" height="32"
alt="Module Index" width="32"></a></td>
<td><A href="genindex.html" tppabs="http://www.python.org/doc/current/lib/genindex.html"><img src="index.gif" tppabs="http://www.python.org/doc/current/icons/index.gif" border="0" height="32"
alt="Index" width="32"></A></td>
</tr></table>
<b class="navlabel">Previous:</b> <a class="sectref" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">17.1.6 Examples</A>
<b class="navlabel">Up:</b> <a class="sectref" href="AST_Examples.html" tppabs="http://www.python.org/doc/current/lib/AST_Examples.html">17.1.6 Examples</A>
<b class="navlabel">Next:</b> <a class="sectref" HREF="node377.html" tppabs="http://www.python.org/doc/current/lib/node377.html">17.1.6.2 Information Discovery</A>
</DIV>
<!--End of Navigation Panel-->
<ADDRESS>
<hr>See <i><a href="about.html" tppabs="http://www.python.org/doc/current/lib/about.html">About this document...</a></i> for information on suggesting changes.
</ADDRESS>
</BODY>
</HTML>
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -