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1 # copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved. | |
2 # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr | |
3 # copyright 2003-2010 Sylvain Thenault, all rights reserved. | |
4 # contact mailto:thenault@gmail.com | |
5 # | |
6 # This file is part of logilab-astng. | |
7 # | |
8 # logilab-astng is free software: you can redistribute it and/or modify it | |
9 # under the terms of the GNU Lesser General Public License as published by the | |
10 # Free Software Foundation, either version 2.1 of the License, or (at your | |
11 # option) any later version. | |
12 # | |
13 # logilab-astng is distributed in the hope that it will be useful, but | |
14 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 # FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
16 # for more details. | |
17 # | |
18 # You should have received a copy of the GNU Lesser General Public License along | |
19 # with logilab-astng. If not, see <http://www.gnu.org/licenses/>. | |
20 """this module contains some utilities to navigate in the tree or to | |
21 extract information from it | |
22 """ | |
23 | |
24 __docformat__ = "restructuredtext en" | |
25 | |
26 from logilab.astng.exceptions import ASTNGBuildingException | |
27 | |
28 | |
29 class ASTWalker: | |
30 """a walker visiting a tree in preorder, calling on the handler: | |
31 | |
32 * visit_<class name> on entering a node, where class name is the class of | |
33 the node in lower case | |
34 | |
35 * leave_<class name> on leaving a node, where class name is the class of | |
36 the node in lower case | |
37 """ | |
38 | |
39 def __init__(self, handler): | |
40 self.handler = handler | |
41 self._cache = {} | |
42 | |
43 def walk(self, node, _done=None): | |
44 """walk on the tree from <node>, getting callbacks from handler""" | |
45 if _done is None: | |
46 _done = set() | |
47 if node in _done: | |
48 raise AssertionError((id(node), node, node.parent)) | |
49 _done.add(node) | |
50 self.visit(node) | |
51 for child_node in node.get_children(): | |
52 self.handler.set_context(node, child_node) | |
53 assert child_node is not node | |
54 self.walk(child_node, _done) | |
55 self.leave(node) | |
56 assert node.parent is not node | |
57 | |
58 def get_callbacks(self, node): | |
59 """get callbacks from handler for the visited node""" | |
60 klass = node.__class__ | |
61 methods = self._cache.get(klass) | |
62 if methods is None: | |
63 handler = self.handler | |
64 kid = klass.__name__.lower() | |
65 e_method = getattr(handler, 'visit_%s' % kid, | |
66 getattr(handler, 'visit_default', None)) | |
67 l_method = getattr(handler, 'leave_%s' % kid, | |
68 getattr(handler, 'leave_default', None)) | |
69 self._cache[klass] = (e_method, l_method) | |
70 else: | |
71 e_method, l_method = methods | |
72 return e_method, l_method | |
73 | |
74 def visit(self, node): | |
75 """walk on the tree from <node>, getting callbacks from handler""" | |
76 method = self.get_callbacks(node)[0] | |
77 if method is not None: | |
78 method(node) | |
79 | |
80 def leave(self, node): | |
81 """walk on the tree from <node>, getting callbacks from handler""" | |
82 method = self.get_callbacks(node)[1] | |
83 if method is not None: | |
84 method(node) | |
85 | |
86 | |
87 class LocalsVisitor(ASTWalker): | |
88 """visit a project by traversing the locals dictionary""" | |
89 def __init__(self): | |
90 ASTWalker.__init__(self, self) | |
91 self._visited = {} | |
92 | |
93 def visit(self, node): | |
94 """launch the visit starting from the given node""" | |
95 if node in self._visited: | |
96 return | |
97 self._visited[node] = 1 # FIXME: use set ? | |
98 methods = self.get_callbacks(node) | |
99 if methods[0] is not None: | |
100 methods[0](node) | |
101 if 'locals' in node.__dict__: # skip Instance and other proxy | |
102 for name, local_node in node.items(): | |
103 self.visit(local_node) | |
104 if methods[1] is not None: | |
105 return methods[1](node) | |
106 | |
107 | |
108 def _check_children(node): | |
109 """a helper function to check children - parent relations""" | |
110 for child in node.get_children(): | |
111 ok = False | |
112 if child is None: | |
113 print "Hm, child of %s is None" % node | |
114 continue | |
115 if not hasattr(child, 'parent'): | |
116 print " ERROR: %s has child %s %x with no parent" % (node, child, id
(child)) | |
117 elif not child.parent: | |
118 print " ERROR: %s has child %s %x with parent %r" % (node, child, id
(child), child.parent) | |
119 elif child.parent is not node: | |
120 print " ERROR: %s %x has child %s %x with wrong parent %s" % (node, | |
121 id(node), child, id(child), child.parent) | |
122 else: | |
123 ok = True | |
124 if not ok: | |
125 print "lines;", node.lineno, child.lineno | |
126 print "of module", node.root(), node.root().name | |
127 raise ASTNGBuildingException | |
128 _check_children(child) | |
129 | |
130 | |
131 from _ast import PyCF_ONLY_AST | |
132 def parse(string): | |
133 return compile(string, "<string>", 'exec', PyCF_ONLY_AST) | |
134 | |
135 class TreeTester(object): | |
136 '''A helper class to see _ast tree and compare with astng tree | |
137 | |
138 indent: string for tree indent representation | |
139 lineno: bool to tell if we should print the line numbers | |
140 | |
141 >>> tester = TreeTester('print') | |
142 >>> print tester.native_tree_repr() | |
143 | |
144 <Module> | |
145 . body = [ | |
146 . <Print> | |
147 . . nl = True | |
148 . ] | |
149 >>> print tester.astng_tree_repr() | |
150 Module() | |
151 body = [ | |
152 Print() | |
153 dest = | |
154 values = [ | |
155 ] | |
156 ] | |
157 ''' | |
158 | |
159 indent = '. ' | |
160 lineno = False | |
161 | |
162 def __init__(self, sourcecode): | |
163 self._string = '' | |
164 self.sourcecode = sourcecode | |
165 self._ast_node = None | |
166 self.build_ast() | |
167 | |
168 def build_ast(self): | |
169 """build the _ast tree from the source code""" | |
170 self._ast_node = parse(self.sourcecode) | |
171 | |
172 def native_tree_repr(self, node=None, indent=''): | |
173 """get a nice representation of the _ast tree""" | |
174 self._string = '' | |
175 if node is None: | |
176 node = self._ast_node | |
177 self._native_repr_tree(node, indent) | |
178 return self._string | |
179 | |
180 | |
181 def _native_repr_tree(self, node, indent, _done=None): | |
182 """recursive method for the native tree representation""" | |
183 from _ast import Load as _Load, Store as _Store, Del as _Del | |
184 from _ast import AST as Node | |
185 if _done is None: | |
186 _done = set() | |
187 if node in _done: | |
188 self._string += '\nloop in tree: %r (%s)' % (node, | |
189 getattr(node, 'lineno', None)) | |
190 return | |
191 _done.add(node) | |
192 self._string += '\n' + indent + '<%s>' % node.__class__.__name__ | |
193 indent += self.indent | |
194 if not hasattr(node, '__dict__'): | |
195 self._string += '\n' + self.indent + " ** node has no __dict__ " + s
tr(node) | |
196 return | |
197 node_dict = node.__dict__ | |
198 if hasattr(node, '_attributes'): | |
199 for a in node._attributes: | |
200 attr = node_dict[a] | |
201 if attr is None: | |
202 continue | |
203 if a in ("lineno", "col_offset") and not self.lineno: | |
204 continue | |
205 self._string +='\n' + indent + a + " = " + repr(attr) | |
206 for field in node._fields or (): | |
207 attr = node_dict[field] | |
208 if attr is None: | |
209 continue | |
210 if isinstance(attr, list): | |
211 if not attr: | |
212 continue | |
213 self._string += '\n' + indent + field + ' = [' | |
214 for elt in attr: | |
215 self._native_repr_tree(elt, indent, _done) | |
216 self._string += '\n' + indent + ']' | |
217 continue | |
218 if isinstance(attr, (_Load, _Store, _Del)): | |
219 continue | |
220 if isinstance(attr, Node): | |
221 self._string += '\n' + indent + field + " = " | |
222 self._native_repr_tree(attr, indent, _done) | |
223 else: | |
224 self._string += '\n' + indent + field + " = " + repr(attr) | |
225 | |
226 | |
227 def build_astng_tree(self): | |
228 """build astng tree from the _ast tree | |
229 """ | |
230 from logilab.astng.builder import ASTNGBuilder | |
231 tree = ASTNGBuilder().string_build(self.sourcecode) | |
232 return tree | |
233 | |
234 def astng_tree_repr(self, ids=False): | |
235 """build the astng tree and return a nice tree representation""" | |
236 mod = self.build_astng_tree() | |
237 return mod.repr_tree(ids) | |
238 | |
239 | |
240 __all__ = ('LocalsVisitor', 'ASTWalker',) | |
241 | |
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