"""Simple code to extract class & function docstrings from a module.
This code is used as an example in the library reference manual in the
section on using the parser module. Refer to the manual for a thorough
discussion of the operation of this code.
"""
import os
import parser
import symbol
import token
import types
from types import ListType, TupleType
def get_docs(fileName):
"""Retrieve information from the parse tree of a source file.
fileName
Name of the file to read Python source code from.
"""
source = open(fileName).read()
basename = os.path.basename(os.path.splitext(fileName)[0])
ast = parser.suite(source)
return ModuleInfo(ast.totuple(), basename)
class SuiteInfoBase:
_docstring = ''
_name = ''
def __init__(self, tree = None):
self._class_info = {}
self._function_info = {}
if tree:
self._extract_info(tree)
def _extract_info(self, tree):
# extract docstring
if len(tree) == 2:
found, vars = match(DOCSTRING_STMT_PATTERN[1], tree[1])
else:
found, vars = match(DOCSTRING_STMT_PATTERN, tree[3])
if found:
self._docstring = eval(vars['docstring'])
# discover inner definitions
for node in tree[1:]:
found, vars = match(COMPOUND_STMT_PATTERN, node)
if found:
cstmt = vars['compound']
if cstmt[0] == symbol.funcdef:
name = cstmt[2][1]
self._function_info[name] = FunctionInfo(cstmt)
elif cstmt[0] == symbol.classdef:
name = cstmt[2][1]
self._class_info[name] = ClassInfo(cstmt)
def get_docstring(self):
return self._docstring
def get_name(self):
return self._name
def get_class_names(self):
return self._class_info.keys()
def get_class_info(self, name):
return self._class_info[name]
def __getitem__(self, name):
try:
return self._class_info[name]
except KeyError:
return self._function_info[name]
class SuiteFuncInfo:
# Mixin class providing access to function names and info.
def get_function_names(self):
return self._function_info.keys()
def get_function_info(self, name):
return self._function_info[name]
class FunctionInfo(SuiteInfoBase, SuiteFuncInfo):
def __init__(self, tree = None):
self._name = tree[2][1]
SuiteInfoBase.__init__(self, tree and tree[-1] or None)
class ClassInfo(SuiteInfoBase):
def __init__(self, tree = None):
self._name = tree[2][1]
SuiteInfoBase.__init__(self, tree and tree[-1] or None)
def get_method_names(self):
return self._function_info.keys()
def get_method_info(self, name):
return self._function_info[name]
class ModuleInfo(SuiteInfoBase, SuiteFuncInfo):
def __init__(self, tree = None, name = "<string>"):
self._name = name
SuiteInfoBase.__init__(self, tree)
if tree:
found, vars = match(DOCSTRING_STMT_PATTERN, tree[1])
if found:
self._docstring = vars["docstring"]
def match(pattern, data, vars=None):
"""Match `data' to `pattern', with variable extraction.
pattern
Pattern to match against, possibly containing variables.
data
Data to be checked and against which variables are extracted.
vars
Dictionary of variables which have already been found. If not
provided, an empty dictionary is created.
The `pattern' value may contain variables of the form ['varname'] which
are allowed to match anything. The value that is matched is returned as
part of a dictionary which maps 'varname' to the matched value. 'varname'
is not required to be a string object, but using strings makes patterns
and the code which uses them more readable.
This function returns two values: a boolean indicating whether a match
was found and a dictionary mapping variable names to their associated
values.
"""
if vars is None:
vars = {}
if type(pattern) is ListType: # 'variables' are ['varname']
vars[pattern[0]] = data
return 1, vars
if type(pattern) is not TupleType:
return (pattern == data), vars
if len(data) != len(pattern):
return 0, vars
for pattern, data in map(None, pattern, data):
same, vars = match(pattern, data, vars)
if not same:
break
return same, vars
# This pattern identifies compound statements, allowing them to be readily
# differentiated from simple statements.
#
COMPOUND_STMT_PATTERN = (
symbol.stmt,
(symbol.compound_stmt, ['compound'])
)
# This pattern will match a 'stmt' node which *might* represent a docstring;
# docstrings require that the statement which provides the docstring be the
# first statement in the class or function, which this pattern does not check.
#
DOCSTRING_STMT_PATTERN = (
symbol.stmt,
(symbol.simple_stmt,
(symbol.small_stmt,
(symbol.expr_stmt,
(symbol.testlist,
(symbol.test,
(symbol.and_test,
(symbol.not_test,
(symbol.comparison,
(symbol.expr,
(symbol.xor_expr,
(symbol.and_expr,
(symbol.shift_expr,
(symbol.arith_expr,
(symbol.term,
(symbol.factor,
(symbol.power,
(symbol.atom,
(token.STRING, ['docstring'])
)))))))))))))))),
(token.NEWLINE, '')
))
