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from string import Template |
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class ASTCodeGenerator(object): |
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def __init__(self, cfg_filename='_c_ast.cfg'): |
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""" Initialize the code generator from a configuration |
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file. |
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""" |
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self.cfg_filename = cfg_filename |
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self.node_cfg = [NodeCfg(name, contents) |
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for (name, contents) in self.parse_cfgfile(cfg_filename)] |
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def generate(self, file=None): |
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""" Generates the code into file, an open file buffer. |
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""" |
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src = Template(_PROLOGUE_COMMENT).substitute( |
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cfg_filename=self.cfg_filename) |
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src += _PROLOGUE_CODE |
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for node_cfg in self.node_cfg: |
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src += node_cfg.generate_source() + '\n\n' |
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file.write(src) |
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def parse_cfgfile(self, filename): |
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""" Parse the configuration file and yield pairs of |
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(name, contents) for each node. |
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""" |
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with open(filename, "r") as f: |
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for line in f: |
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line = line.strip() |
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if not line or line.startswith('#'): |
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continue |
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colon_i = line.find(':') |
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lbracket_i = line.find('[') |
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rbracket_i = line.find(']') |
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if colon_i < 1 or lbracket_i <= colon_i or rbracket_i <= lbracket_i: |
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raise RuntimeError("Invalid line in %s:\n%s\n" % (filename, line)) |
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name = line[:colon_i] |
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val = line[lbracket_i + 1:rbracket_i] |
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vallist = [v.strip() for v in val.split(',')] if val else [] |
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yield name, vallist |
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class NodeCfg(object): |
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""" Node configuration. |
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name: node name |
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contents: a list of contents - attributes and child nodes |
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See comment at the top of the configuration file for details. |
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""" |
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def __init__(self, name, contents): |
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self.name = name |
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self.all_entries = [] |
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self.attr = [] |
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self.child = [] |
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self.seq_child = [] |
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for entry in contents: |
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clean_entry = entry.rstrip('*') |
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self.all_entries.append(clean_entry) |
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if entry.endswith('**'): |
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self.seq_child.append(clean_entry) |
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elif entry.endswith('*'): |
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self.child.append(clean_entry) |
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else: |
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self.attr.append(entry) |
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def generate_source(self): |
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src = self._gen_init() |
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src += '\n' + self._gen_children() |
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src += '\n' + self._gen_iter() |
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src += '\n' + self._gen_attr_names() |
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return src |
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def _gen_init(self): |
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src = "class %s(Node):\n" % self.name |
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if self.all_entries: |
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args = ', '.join(self.all_entries) |
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slots = ', '.join("'{0}'".format(e) for e in self.all_entries) |
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slots += ", 'coord', '__weakref__'" |
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arglist = '(self, %s, coord=None)' % args |
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else: |
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slots = "'coord', '__weakref__'" |
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arglist = '(self, coord=None)' |
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src += " __slots__ = (%s)\n" % slots |
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src += " def __init__%s:\n" % arglist |
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for name in self.all_entries + ['coord']: |
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src += " self.%s = %s\n" % (name, name) |
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return src |
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def _gen_children(self): |
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src = ' def children(self):\n' |
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if self.all_entries: |
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src += ' nodelist = []\n' |
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for child in self.child: |
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src += ( |
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' if self.%(child)s is not None:' + |
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' nodelist.append(("%(child)s", self.%(child)s))\n') % ( |
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dict(child=child)) |
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for seq_child in self.seq_child: |
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src += ( |
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' for i, child in enumerate(self.%(child)s or []):\n' |
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' nodelist.append(("%(child)s[%%d]" %% i, child))\n') % ( |
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dict(child=seq_child)) |
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src += ' return tuple(nodelist)\n' |
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else: |
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src += ' return ()\n' |
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return src |
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def _gen_iter(self): |
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src = ' def __iter__(self):\n' |
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if self.all_entries: |
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for child in self.child: |
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src += ( |
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' if self.%(child)s is not None:\n' + |
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' yield self.%(child)s\n') % (dict(child=child)) |
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for seq_child in self.seq_child: |
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src += ( |
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' for child in (self.%(child)s or []):\n' |
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' yield child\n') % (dict(child=seq_child)) |
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if not (self.child or self.seq_child): |
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src += ( |
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' return\n' + |
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' yield\n') |
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else: |
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src += ( |
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' return\n' + |
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' yield\n') |
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return src |
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def _gen_attr_names(self): |
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src = " attr_names = (" + ''.join("%r, " % nm for nm in self.attr) + ')' |
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return src |
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_PROLOGUE_COMMENT = \ |
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r'''#----------------------------------------------------------------- |
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# ** ATTENTION ** |
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# This code was automatically generated from the file: |
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# $cfg_filename |
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# |
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# Do not modify it directly. Modify the configuration file and |
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# run the generator again. |
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# ** ** *** ** ** |
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# |
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# pycparser: c_ast.py |
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# |
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# AST Node classes. |
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# |
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# Eli Bendersky [https://eli.thegreenplace.net/] |
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# License: BSD |
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#----------------------------------------------------------------- |
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''' |
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_PROLOGUE_CODE = r''' |
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import sys |
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def _repr(obj): |
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""" |
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Get the representation of an object, with dedicated pprint-like format for lists. |
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""" |
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if isinstance(obj, list): |
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return '[' + (',\n '.join((_repr(e).replace('\n', '\n ') for e in obj))) + '\n]' |
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else: |
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return repr(obj) |
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class Node(object): |
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__slots__ = () |
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""" Abstract base class for AST nodes. |
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""" |
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def __repr__(self): |
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""" Generates a python representation of the current node |
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""" |
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result = self.__class__.__name__ + '(' |
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indent = '' |
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separator = '' |
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for name in self.__slots__[:-2]: |
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result += separator |
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result += indent |
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result += name + '=' + (_repr(getattr(self, name)).replace('\n', '\n ' + (' ' * (len(name) + len(self.__class__.__name__))))) |
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separator = ',' |
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indent = '\n ' + (' ' * len(self.__class__.__name__)) |
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result += indent + ')' |
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return result |
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def children(self): |
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""" A sequence of all children that are Nodes |
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""" |
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pass |
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def show(self, buf=sys.stdout, offset=0, attrnames=False, nodenames=False, showcoord=False, _my_node_name=None): |
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""" Pretty print the Node and all its attributes and |
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children (recursively) to a buffer. |
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buf: |
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Open IO buffer into which the Node is printed. |
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offset: |
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Initial offset (amount of leading spaces) |
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attrnames: |
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True if you want to see the attribute names in |
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name=value pairs. False to only see the values. |
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nodenames: |
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True if you want to see the actual node names |
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within their parents. |
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showcoord: |
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Do you want the coordinates of each Node to be |
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displayed. |
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""" |
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lead = ' ' * offset |
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if nodenames and _my_node_name is not None: |
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buf.write(lead + self.__class__.__name__+ ' <' + _my_node_name + '>: ') |
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else: |
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buf.write(lead + self.__class__.__name__+ ': ') |
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if self.attr_names: |
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if attrnames: |
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nvlist = [(n, getattr(self,n)) for n in self.attr_names] |
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attrstr = ', '.join('%s=%s' % nv for nv in nvlist) |
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else: |
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vlist = [getattr(self, n) for n in self.attr_names] |
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attrstr = ', '.join('%s' % v for v in vlist) |
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buf.write(attrstr) |
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if showcoord: |
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buf.write(' (at %s)' % self.coord) |
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buf.write('\n') |
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for (child_name, child) in self.children(): |
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child.show( |
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buf, |
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offset=offset + 2, |
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attrnames=attrnames, |
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nodenames=nodenames, |
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showcoord=showcoord, |
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_my_node_name=child_name) |
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|
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class NodeVisitor(object): |
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""" A base NodeVisitor class for visiting c_ast nodes. |
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Subclass it and define your own visit_XXX methods, where |
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XXX is the class name you want to visit with these |
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methods. |
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For example: |
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|
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class ConstantVisitor(NodeVisitor): |
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def __init__(self): |
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self.values = [] |
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|
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def visit_Constant(self, node): |
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self.values.append(node.value) |
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Creates a list of values of all the constant nodes |
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encountered below the given node. To use it: |
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cv = ConstantVisitor() |
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cv.visit(node) |
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Notes: |
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* generic_visit() will be called for AST nodes for which |
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no visit_XXX method was defined. |
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* The children of nodes for which a visit_XXX was |
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defined will not be visited - if you need this, call |
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generic_visit() on the node. |
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You can use: |
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NodeVisitor.generic_visit(self, node) |
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* Modeled after Python's own AST visiting facilities |
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(the ast module of Python 3.0) |
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""" |
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_method_cache = None |
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|
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def visit(self, node): |
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""" Visit a node. |
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""" |
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|
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if self._method_cache is None: |
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self._method_cache = {} |
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visitor = self._method_cache.get(node.__class__.__name__, None) |
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if visitor is None: |
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method = 'visit_' + node.__class__.__name__ |
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visitor = getattr(self, method, self.generic_visit) |
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self._method_cache[node.__class__.__name__] = visitor |
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return visitor(node) |
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def generic_visit(self, node): |
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""" Called if no explicit visitor function exists for a |
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node. Implements preorder visiting of the node. |
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""" |
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for c in node: |
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self.visit(c) |
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''' |
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