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<H2><A NAME="SECTION0051440000000000000000"></A>
<BR>
3.14.4 Exceptions and Error Handling
</H2>

<P>
The parser module defines a single exception, but may also pass other
built-in exceptions from other portions of the Python runtime
environment.  See each function for information about the exceptions
it can raise.

<P>
<dl><dt><b><a name="l2h-491"><tt class=exception>ParserError</tt></a></b>
<dd>
Exception raised when a failure occurs within the parser module.  This
is generally produced for validation failures rather than the built in
<tt class=exception>SyntaxError</tt> thrown during normal parsing.
The exception argument is either a string describing the reason of the
failure or a tuple containing a sequence causing the failure from a parse
tree passed to <tt class=function>sequence2ast()</tt> and an explanatory string.  Calls to
<tt class=function>sequence2ast()</tt> need to be able to handle either type of exception,
while calls to other functions in the module will only need to be
aware of the simple string values.
</dl>

<P>
Note that the functions <tt class=function>compileast()</tt>, <tt class=function>expr()</tt>, and
<tt class=function>suite()</tt> may throw exceptions which are normally thrown by the
parsing and compilation process.  These include the built in
exceptions <tt class=exception>MemoryError</tt>, <tt class=exception>OverflowError</tt>,
<tt class=exception>SyntaxError</tt>, and <tt class=exception>SystemError</tt>.  In these cases, these
exceptions carry all the meaning normally associated with them.  Refer
to the descriptions of each function for detailed information.

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