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(python2.1-lib.info)Converting AST Objects

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Converting AST Objects
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AST objects, regardless of the input used to create them, may be
converted to parse trees represented as list- or tuple- trees, or may
be compiled into executable code objects.  Parse trees may be extracted
with or without line numbering information.

`ast2list(ast[, line_info])'
     This function accepts an AST object from the caller in AST and
     returns a Python list representing the equivalent parse tree.  The
     resulting list representation can be used for inspection or the
     creation of a new parse tree in list form.  This function does not
     fail so long as memory is available to build the list
     representation.  If the parse tree will only be used for
     inspection, `ast2tuple()' should be used instead to reduce memory
     consumption and fragmentation.  When the list representation is
     required, this function is significantly faster than retrieving a
     tuple representation and converting that to nested lists.

     If LINE_INFO is true, line number information will be included for
     all terminal tokens as a third element of the list representing
     the token.  Note that the line number provided specifies the line
     on which the token _ends_.  This information is omitted if the
     flag is false or omitted.

`ast2tuple(ast[, line_info])'
     This function accepts an AST object from the caller in AST and
     returns a Python tuple representing the equivalent parse tree.
     Other than returning a tuple instead of a list, this function is
     identical to `ast2list()'.

     If LINE_INFO is true, line number information will be included for
     all terminal tokens as a third element of the list representing
     the token.  This information is omitted if the flag is false or
     omitted.

`compileast(ast[, filename` = '<ast>''])'
     The Python byte compiler can be invoked on an AST object to produce
     code objects which can be used as part of an `exec' statement or a
     call to the built-in `eval()'  function.  This function provides
     the interface to the compiler, passing the internal parse tree
     from AST to the parser, using the source file name specified by
     the FILENAME parameter.  The default value supplied for FILENAME
     indicates that the source was an AST object.

     Compiling an AST object may result in exceptions related to
     compilation; an example would be a `SyntaxError' caused by the
     parse tree for `del f(0)': this statement is considered legal
     within the formal grammar for Python but is not a legal language
     construct.  The `SyntaxError' raised for this condition is
     actually generated by the Python byte-compiler normally, which is
     why it can be raised at this point by the `parser' module.  Most
     causes of compilation failure can be diagnosed programmatically by
     inspection of the parse tree.