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(import "ast")


    

    
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(ast)

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??ast


    

    




Help on module ast:

NAME
    ast

MODULE REFERENCE
    http://docs.python.org/3.4/library/ast
    
    The following documentation is automatically generated from the Python
    source files.  It may be incomplete, incorrect or include features that
    are considered implementation detail and may vary between Python
    implementations.  When in doubt, consult the module reference at the
    location listed above.

DESCRIPTION
    ast
    ~~~
    
    The `ast` module helps Python applications to process trees of the Python
    abstract syntax grammar.  The abstract syntax itself might change with
    each Python release; this module helps to find out programmatically what
    the current grammar looks like and allows modifications of it.
    
    An abstract syntax tree can be generated by passing `ast.PyCF_ONLY_AST` as
    a flag to the `compile()` builtin function or by using the `parse()`
    function from this module.  The result will be a tree of objects whose
    classes all inherit from `ast.AST`.
    
    A modified abstract syntax tree can be compiled into a Python code object
    using the built-in `compile()` function.
    
    Additionally various helper functions are provided that make working with
    the trees simpler.  The main intention of the helper functions and this
    module in general is to provide an easy to use interface for libraries
    that work tightly with the python syntax (template engines for example).
    
    
    :copyright: Copyright 2008 by Armin Ronacher.
    :license: Python License.

CLASSES
    builtins.object
        NodeVisitor
            NodeTransformer
    
    class NodeTransformer(NodeVisitor)
     |  A :class:`NodeVisitor` subclass that walks the abstract syntax tree and
     |  allows modification of nodes.
     |  
     |  The `NodeTransformer` will walk the AST and use the return value of the
     |  visitor methods to replace or remove the old node.  If the return value of
     |  the visitor method is ``None``, the node will be removed from its location,
     |  otherwise it is replaced with the return value.  The return value may be the
     |  original node in which case no replacement takes place.
     |  
     |  Here is an example transformer that rewrites all occurrences of name lookups
     |  (``foo``) to ``data['foo']``::
     |  
     |     class RewriteName(NodeTransformer):
     |  
     |         def visit_Name(self, node):
     |             return copy_location(Subscript(
     |                 value=Name(id='data', ctx=Load()),
     |                 slice=Index(value=Str(s=node.id)),
     |                 ctx=node.ctx
     |             ), node)
     |  
     |  Keep in mind that if the node you're operating on has child nodes you must
     |  either transform the child nodes yourself or call the :meth:`generic_visit`
     |  method for the node first.
     |  
     |  For nodes that were part of a collection of statements (that applies to all
     |  statement nodes), the visitor may also return a list of nodes rather than
     |  just a single node.
     |  
     |  Usually you use the transformer like this::
     |  
     |     node = YourTransformer().visit(node)
     |  
     |  Method resolution order:
     |      NodeTransformer
     |      NodeVisitor
     |      builtins.object
     |  
     |  Methods defined here:
     |  
     |  generic_visit(self, node)
     |  
     |  ----------------------------------------------------------------------
     |  Methods inherited from NodeVisitor:
     |  
     |  visit(self, node)
     |      Visit a node.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors inherited from NodeVisitor:
     |  
     |  __dict__
     |      dictionary for instance variables (if defined)
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)
    
    class NodeVisitor(builtins.object)
     |  A node visitor base class that walks the abstract syntax tree and calls a
     |  visitor function for every node found.  This function may return a value
     |  which is forwarded by the `visit` method.
     |  
     |  This class is meant to be subclassed, with the subclass adding visitor
     |  methods.
     |  
     |  Per default the visitor functions for the nodes are ``'visit_'`` +
     |  class name of the node.  So a `TryFinally` node visit function would
     |  be `visit_TryFinally`.  This behavior can be changed by overriding
     |  the `visit` method.  If no visitor function exists for a node
     |  (return value `None`) the `generic_visit` visitor is used instead.
     |  
     |  Don't use the `NodeVisitor` if you want to apply changes to nodes during
     |  traversing.  For this a special visitor exists (`NodeTransformer`) that
     |  allows modifications.
     |  
     |  Methods defined here:
     |  
     |  generic_visit(self, node)
     |      Called if no explicit visitor function exists for a node.
     |  
     |  visit(self, node)
     |      Visit a node.
     |  
     |  ----------------------------------------------------------------------
     |  Data descriptors defined here:
     |  
     |  __dict__
     |      dictionary for instance variables (if defined)
     |  
     |  __weakref__
     |      list of weak references to the object (if defined)

FUNCTIONS
    copy_location(new_node, old_node)
        Copy source location (`lineno` and `col_offset` attributes) from
        *old_node* to *new_node* if possible, and return *new_node*.
    
    dump(node, annotate_fields=True, include_attributes=False)
        Return a formatted dump of the tree in *node*.  This is mainly useful for
        debugging purposes.  The returned string will show the names and the values
        for fields.  This makes the code impossible to evaluate, so if evaluation is
        wanted *annotate_fields* must be set to False.  Attributes such as line
        numbers and column offsets are not dumped by default.  If this is wanted,
        *include_attributes* can be set to True.
    
    fix_missing_locations(node)
        When you compile a node tree with compile(), the compiler expects lineno and
        col_offset attributes for every node that supports them.  This is rather
        tedious to fill in for generated nodes, so this helper adds these attributes
        recursively where not already set, by setting them to the values of the
        parent node.  It works recursively starting at *node*.
    
    get_docstring(node, clean=True)
        Return the docstring for the given node or None if no docstring can
        be found.  If the node provided does not have docstrings a TypeError
        will be raised.
    
    increment_lineno(node, n=1)
        Increment the line number of each node in the tree starting at *node* by *n*.
        This is useful to "move code" to a different location in a file.
    
    iter_child_nodes(node)
        Yield all direct child nodes of *node*, that is, all fields that are nodes
        and all items of fields that are lists of nodes.
    
    iter_fields(node)
        Yield a tuple of ``(fieldname, value)`` for each field in ``node._fields``
        that is present on *node*.
    
    literal_eval(node_or_string)
        Safely evaluate an expression node or a string containing a Python
        expression.  The string or node provided may only consist of the following
        Python literal structures: strings, bytes, numbers, tuples, lists, dicts,
        sets, booleans, and None.
    
    parse(source, filename='<unknown>', mode='exec')
        Parse the source into an AST node.
        Equivalent to compile(source, filename, mode, PyCF_ONLY_AST).
    
    walk(node)
        Recursively yield all descendant nodes in the tree starting at *node*
        (including *node* itself), in no specified order.  This is useful if you
        only want to modify nodes in place and don't care about the context.

DATA
    PyCF_ONLY_AST = 1024

FILE
    /usr/lib/python3.4/ast.py

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?dir


    

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;; which is still a bug


    

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(read-char)


    

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(eof-object?)


    

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(define! x 5)


    

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x


    

    
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5

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%%python

print(x)


    

    




Traceback (most recent call last):
  File "/usr/local/lib/python3.4/dist-packages/metakernel-0.13.3-py3.4.egg/metakernel/magics/python_magic.py", line 19, in exec_code
    exec(code, env)
  File "<string>", line 1, in <module>
NameError: name 'x' is not defined

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%%python

import calysto_scheme

globals().update(calysto_scheme.scheme.ENVIRONMENT)
calysto_scheme.scheme.ENVIRONMENT = globals()

print(x)


    

    




5

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(define! y 7)


    

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%%python

print(y)


    

    




7

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((getitem (globals) "keys"))


    

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%%scheme

(print y)


    

    




7






    
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<void>

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(try 1
     (finally (define XXX 1)))


    

    
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1

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XXX


    

    
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1

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(try 1
     (finally 2))


    

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(try 
 XXX
 (catch e e 
        (raise "ERROR"))) ;; this is the bug


    

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(member 'set! (dir))


    

    
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#f

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(member 'set-cdr! (dir))


    

    
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(set-cdr! setitem snoc sort sqrt string string->list string->number string->symbol string-append string-length string-ref string-split string<? string=? string? substring symbol symbol->string symbol? typeof unparse unparse-procedure use-lexical-address use-stack-trace use-tracing vector vector->list vector-length vector-ref vector-set! vector? void zero?)

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(dir)


    

    
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(% * + - / // < <= = > >= SCHEMEPATH abort abs and append apply assq assv atom? boolean? caaaar caaadr caaar caadar caaddr caadr caar cadaar cadadr cadar caddar cadddr caddr cadr call-with-current-continuation call/cc car case cases cd cdaaar cdaadr cdaar cdadar cdaddr cdadr cdar cddaar cddadr cddar cdddar cddddr cdddr cddr cdr char->integer char->string char-alphabetic? char-numeric? char-whitespace? char=? char? cond cons contains current-directory current-environment current-time cut define-datatype dict dir display div eq? equal? eqv? error eval eval-ast even? exit float for-each format get get-stack-trace getitem globals import import-as import-from int integer->char iter? length let let* letrec list list->string list->vector list-ref list? load load-as make-set make-vector map max member memq memv min mod modulo newline not null? number->string number? odd? or pair? parse parse-string print printf procedure? property python-eval python-exec quotient rac range rational rdc read-string record-case remainder require reset-toplevel-env reverse round set-car! set-cdr! setitem snoc sort sqrt string string->list string->number string->symbol string-append string-length string-ref string-split string<? string=? string? substring symbol symbol->string symbol? typeof unparse unparse-procedure use-lexical-address use-stack-trace use-tracing vector vector->list vector-length vector-ref vector-set! vector? void zero?)

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