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<title>18.1.6.1 Emulation of compile()</title>
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<H3><A NAME="SECTION0020161000000000000000">
18.1.6.1 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>
<div class="verbatim"><pre>
>>> code = compile('a + 5', 'file.py', 'eval')
>>> a = 5
>>> eval(code)
10
</pre></div>
<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>
<div class="verbatim"><pre>
>>> import parser
>>> ast = parser.expr('a + 5')
>>> code = ast.compile('file.py')
>>> a = 5
>>> eval(code)
10
</pre></div>
<P>
An application which needs both AST and code objects can package this
code into readily available functions:
<P>
<div class="verbatim"><pre>
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></div>
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<span class="release-info">Release 2.4.3, documentation updated on 29 March 2006.</span>
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