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| 1 | +"""Simple code to extract class & function docstrings from a module. | |
| 2 | + | |
| 3 | +This code is used as an example in the library reference manual in the | |
| 4 | +section on using the parser module. Refer to the manual for a thorough | |
| 5 | +discussion of the operation of this code. | |
| 6 | +""" | |
| 7 | + | |
| 8 | +import os | |
| 9 | +import parser | |
| 10 | +import symbol | |
| 11 | +import token | |
| 12 | +import types | |
| 13 | + | |
| 14 | +from types import ListType, TupleType | |
| 15 | + | |
| 16 | + | |
| 17 | +def get_docs(fileName): | |
| 18 | + """Retrieve information from the parse tree of a source file. | |
| 19 | + | |
| 20 | + fileName | |
| 21 | + Name of the file to read Python source code from. | |
| 22 | + """ | |
| 23 | + source = open(fileName).read() | |
| 24 | + basename = os.path.basename(os.path.splitext(fileName)[0]) | |
| 25 | + ast = parser.suite(source) | |
| 26 | + return ModuleInfo(ast.totuple(), basename) | |
| 27 | + | |
| 28 | + | |
| 29 | +class SuiteInfoBase: | |
| 30 | + _docstring = '' | |
| 31 | + _name = '' | |
| 32 | + | |
| 33 | + def __init__(self, tree = None): | |
| 34 | + self._class_info = {} | |
| 35 | + self._function_info = {} | |
| 36 | + if tree: | |
| 37 | + self._extract_info(tree) | |
| 38 | + | |
| 39 | + def _extract_info(self, tree): | |
| 40 | + # extract docstring | |
| 41 | + if len(tree) == 2: | |
| 42 | + found, vars = match(DOCSTRING_STMT_PATTERN[1], tree[1]) | |
| 43 | + else: | |
| 44 | + found, vars = match(DOCSTRING_STMT_PATTERN, tree[3]) | |
| 45 | + if found: | |
| 46 | + self._docstring = eval(vars['docstring']) | |
| 47 | + # discover inner definitions | |
| 48 | + for node in tree[1:]: | |
| 49 | + found, vars = match(COMPOUND_STMT_PATTERN, node) | |
| 50 | + if found: | |
| 51 | + cstmt = vars['compound'] | |
| 52 | + if cstmt[0] == symbol.funcdef: | |
| 53 | + name = cstmt[2][1] | |
| 54 | + self._function_info[name] = FunctionInfo(cstmt) | |
| 55 | + elif cstmt[0] == symbol.classdef: | |
| 56 | + name = cstmt[2][1] | |
| 57 | + self._class_info[name] = ClassInfo(cstmt) | |
| 58 | + | |
| 59 | + def get_docstring(self): | |
| 60 | + return self._docstring | |
| 61 | + | |
| 62 | + def get_name(self): | |
| 63 | + return self._name | |
| 64 | + | |
| 65 | + def get_class_names(self): | |
| 66 | + return self._class_info.keys() | |
| 67 | + | |
| 68 | + def get_class_info(self, name): | |
| 69 | + return self._class_info[name] | |
| 70 | + | |
| 71 | + def __getitem__(self, name): | |
| 72 | + try: | |
| 73 | + return self._class_info[name] | |
| 74 | + except KeyError: | |
| 75 | + return self._function_info[name] | |
| 76 | + | |
| 77 | + | |
| 78 | +class SuiteFuncInfo: | |
| 79 | + # Mixin class providing access to function names and info. | |
| 80 | + | |
| 81 | + def get_function_names(self): | |
| 82 | + return self._function_info.keys() | |
| 83 | + | |
| 84 | + def get_function_info(self, name): | |
| 85 | + return self._function_info[name] | |
| 86 | + | |
| 87 | + | |
| 88 | +class FunctionInfo(SuiteInfoBase, SuiteFuncInfo): | |
| 89 | + def __init__(self, tree = None): | |
| 90 | + self._name = tree[2][1] | |
| 91 | + SuiteInfoBase.__init__(self, tree and tree[-1] or None) | |
| 92 | + | |
| 93 | + | |
| 94 | +class ClassInfo(SuiteInfoBase): | |
| 95 | + def __init__(self, tree = None): | |
| 96 | + self._name = tree[2][1] | |
| 97 | + SuiteInfoBase.__init__(self, tree and tree[-1] or None) | |
| 98 | + | |
| 99 | + def get_method_names(self): | |
| 100 | + return self._function_info.keys() | |
| 101 | + | |
| 102 | + def get_method_info(self, name): | |
| 103 | + return self._function_info[name] | |
| 104 | + | |
| 105 | + | |
| 106 | +class ModuleInfo(SuiteInfoBase, SuiteFuncInfo): | |
| 107 | + def __init__(self, tree = None, name = "<string>"): | |
| 108 | + self._name = name | |
| 109 | + SuiteInfoBase.__init__(self, tree) | |
| 110 | + if tree: | |
| 111 | + found, vars = match(DOCSTRING_STMT_PATTERN, tree[1]) | |
| 112 | + if found: | |
| 113 | + self._docstring = vars["docstring"] | |
| 114 | + | |
| 115 | + | |
| 116 | +def match(pattern, data, vars=None): | |
| 117 | + """Match `data' to `pattern', with variable extraction. | |
| 118 | + | |
| 119 | + pattern | |
| 120 | + Pattern to match against, possibly containing variables. | |
| 121 | + | |
| 122 | + data | |
| 123 | + Data to be checked and against which variables are extracted. | |
| 124 | + | |
| 125 | + vars | |
| 126 | + Dictionary of variables which have already been found. If not | |
| 127 | + provided, an empty dictionary is created. | |
| 128 | + | |
| 129 | + The `pattern' value may contain variables of the form ['varname'] which | |
| 130 | + are allowed to match anything. The value that is matched is returned as | |
| 131 | + part of a dictionary which maps 'varname' to the matched value. 'varname' | |
| 132 | + is not required to be a string object, but using strings makes patterns | |
| 133 | + and the code which uses them more readable. | |
| 134 | + | |
| 135 | + This function returns two values: a boolean indicating whether a match | |
| 136 | + was found and a dictionary mapping variable names to their associated | |
| 137 | + values. | |
| 138 | + """ | |
| 139 | + if vars is None: | |
| 140 | + vars = {} | |
| 141 | + if type(pattern) is ListType: # 'variables' are ['varname'] | |
| 142 | + vars[pattern[0]] = data | |
| 143 | + return 1, vars | |
| 144 | + if type(pattern) is not TupleType: | |
| 145 | + return (pattern == data), vars | |
| 146 | + if len(data) != len(pattern): | |
| 147 | + return 0, vars | |
| 148 | + for pattern, data in map(None, pattern, data): | |
| 149 | + same, vars = match(pattern, data, vars) | |
| 150 | + if not same: | |
| 151 | + break | |
| 152 | + return same, vars | |
| 153 | + | |
| 154 | + | |
| 155 | +# This pattern identifies compound statements, allowing them to be readily | |
| 156 | +# differentiated from simple statements. | |
| 157 | +# | |
| 158 | +COMPOUND_STMT_PATTERN = ( | |
| 159 | + symbol.stmt, | |
| 160 | + (symbol.compound_stmt, ['compound']) | |
| 161 | + ) | |
| 162 | + | |
| 163 | + | |
| 164 | +# This pattern will match a 'stmt' node which *might* represent a docstring; | |
| 165 | +# docstrings require that the statement which provides the docstring be the | |
| 166 | +# first statement in the class or function, which this pattern does not check. | |
| 167 | +# | |
| 168 | +DOCSTRING_STMT_PATTERN = ( | |
| 169 | + symbol.stmt, | |
| 170 | + (symbol.simple_stmt, | |
| 171 | + (symbol.small_stmt, | |
| 172 | + (symbol.expr_stmt, | |
| 173 | + (symbol.testlist, | |
| 174 | + (symbol.test, | |
| 175 | + (symbol.and_test, | |
| 176 | + (symbol.not_test, | |
| 177 | + (symbol.comparison, | |
| 178 | + (symbol.expr, | |
| 179 | + (symbol.xor_expr, | |
| 180 | + (symbol.and_expr, | |
| 181 | + (symbol.shift_expr, | |
| 182 | + (symbol.arith_expr, | |
| 183 | + (symbol.term, | |
| 184 | + (symbol.factor, | |
| 185 | + (symbol.power, | |
| 186 | + (symbol.atom, | |
| 187 | + (token.STRING, ['docstring']) | |
| 188 | + )))))))))))))))), | |
| 189 | + (token.NEWLINE, '') | |
| 190 | + )) | |