<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <link rel="STYLESHEET" href="lib.css" type='text/css' /> <link rel="SHORTCUT ICON" href="../icons/pyfav.gif" /> <link rel='start' href='../index.html' title='Python Documentation Index' /> <link rel="first" href="lib.html" title='Python Library Reference' /> <link rel='contents' href='contents.html' title="Contents" /> <link rel='index' href='genindex.html' title='Index' /> <link rel='last' href='about.html' title='About this document...' /> <link rel='help' href='about.html' title='About this document...' /> <LINK rel="next" href="node686.html"> <LINK rel="prev" href="node684.html"> <LINK rel="parent" href="module-parser.html"> <LINK rel="next" href="node686.html"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <meta name='aesop' content='information' /> <META name="description" content="Exceptions and Error Handling "> <META name="keywords" content="lib"> <META name="resource-type" content="document"> <META name="distribution" content="global"> <title>18.1.4 Exceptions and Error Handling </title> </head> <body> <DIV CLASS="navigation"> <div id='top-navigation-panel'> <table align="center" width="100%" cellpadding="0" cellspacing="2"> <tr> <td class='online-navigation'><a rel="prev" title="18.1.3 Queries on AST" href="node684.html"><img src='../icons/previous.png' border='0' height='32' alt='Previous Page' width='32' /></A></td> <td class='online-navigation'><a rel="parent" title="18.1 parser " href="module-parser.html"><img src='../icons/up.png' border='0' height='32' alt='Up One Level' width='32' /></A></td> <td class='online-navigation'><a rel="next" title="18.1.5 AST Objects" href="node686.html"><img src='../icons/next.png' border='0' height='32' alt='Next Page' width='32' /></A></td> <td align="center" width="100%">Python Library Reference</td> <td class='online-navigation'><a rel="contents" title="Table of Contents" href="contents.html"><img src='../icons/contents.png' border='0' height='32' alt='Contents' width='32' /></A></td> <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' border='0' height='32' alt='Module Index' width='32' /></a></td> <td class='online-navigation'><a rel="index" title="Index" href="genindex.html"><img src='../icons/index.png' border='0' height='32' alt='Index' width='32' /></A></td> </tr></table> <div class='online-navigation'> <b class="navlabel">Previous:</b> <a class="sectref" rel="prev" href="node684.html">18.1.3 Queries on AST</A> <b class="navlabel">Up:</b> <a class="sectref" rel="parent" href="module-parser.html">18.1 parser </A> <b class="navlabel">Next:</b> <a class="sectref" rel="next" href="node686.html">18.1.5 AST Objects</A> </div> <hr /></div> </DIV> <!--End of Navigation Panel--> <H2><A NAME="SECTION0020140000000000000000"><!--x--></A><A NAME="AST_Errors"><!--z--></A> <BR> 18.1.4 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><span class="typelabel">exception</span> <tt id='l2h-4661' class="exception">ParserError</tt></b></dt> <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. </dd></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. <P> <DIV CLASS="navigation"> <div class='online-navigation'><hr /> <table align="center" width="100%" cellpadding="0" cellspacing="2"> <tr> <td class='online-navigation'><a rel="prev" title="18.1.3 Queries on AST" rel="prev" title="18.1.3 Queries on AST" href="node684.html"><img src='../icons/previous.png' border='0' height='32' alt='Previous Page' width='32' /></A></td> <td class='online-navigation'><a rel="parent" title="18.1 parser " rel="parent" title="18.1 parser " href="module-parser.html"><img src='../icons/up.png' border='0' height='32' alt='Up One Level' width='32' /></A></td> <td class='online-navigation'><a rel="next" title="18.1.5 AST Objects" rel="next" title="18.1.5 AST Objects" href="node686.html"><img src='../icons/next.png' border='0' height='32' alt='Next Page' width='32' /></A></td> <td align="center" width="100%">Python Library Reference</td> <td class='online-navigation'><a rel="contents" title="Table of Contents" rel="contents" title="Table of Contents" href="contents.html"><img src='../icons/contents.png' border='0' height='32' alt='Contents' width='32' /></A></td> <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' border='0' height='32' alt='Module Index' width='32' /></a></td> <td class='online-navigation'><a rel="index" title="Index" rel="index" title="Index" href="genindex.html"><img src='../icons/index.png' border='0' height='32' alt='Index' width='32' /></A></td> </tr></table> <div class='online-navigation'> <b class="navlabel">Previous:</b> <a class="sectref" rel="prev" href="node684.html">18.1.3 Queries on AST</A> <b class="navlabel">Up:</b> <a class="sectref" rel="parent" href="module-parser.html">18.1 parser </A> <b class="navlabel">Next:</b> <a class="sectref" rel="next" href="node686.html">18.1.5 AST Objects</A> </div> </div> <hr /> <span class="release-info">Release 2.3.4, documentation updated on May 20, 2004.</span> </DIV> <!--End of Navigation Panel--> <ADDRESS> See <i><a href="about.html">About this document...</a></i> for information on suggesting changes. </ADDRESS> </BODY> </HTML>
