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17.1.3 Queries on AST Objects
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<P>
Two functions are provided which allow an application to determine if
an AST was created as an expression or a suite. Neither of these
functions can be used to determine if an AST was created from source
code via <tt class="function">expr()</tt> or <tt class="function">suite()</tt> or from a parse tree
via <tt class="function">sequence2ast()</tt>.
<P>
<dl><dt><b><a name='l2h-3020'><tt class='function'>isexpr</tt></a></b> (<var>ast</var>)
<dd>
When <var>ast</var> represents an <code>'eval'</code> form, this function
returns true, otherwise it returns false. This is useful, since code
objects normally cannot be queried for this information using existing
built-in functions. Note that the code objects created by
<tt class="function">compileast()</tt> cannot be queried like this either, and are
identical to those created by the built-in
<tt class="function">compile()</tt> function.
</dl>
<P>
<dl><dt><b><a name='l2h-3021'><tt class='function'>issuite</tt></a></b> (<var>ast</var>)
<dd>
This function mirrors <tt class="function">isexpr()</tt> in that it reports whether an
AST object represents an <code>'exec'</code> form, commonly known as a
``suite.'' It is not safe to assume that this function is equivalent
to "<tt class="samp">not isexpr(<var>ast</var>)</tt>", as additional syntactic fragments may
be supported in the future.
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