blob: 96e533507bb2728478a8d62363dbd0df5c3dcfb1 [file] [log] [blame]
# mako/pyparser.py
# Copyright (C) 2006-2015 the Mako authors and contributors <see AUTHORS file>
#
# This module is part of Mako and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Handles parsing of Python code.
Parsing to AST is done via _ast on Python > 2.5, otherwise the compiler
module is used.
"""
from mako import exceptions, util, compat
from mako.compat import arg_stringname
import operator
if compat.py3k:
# words that cannot be assigned to (notably
# smaller than the total keys in __builtins__)
reserved = set(['True', 'False', 'None', 'print'])
# the "id" attribute on a function node
arg_id = operator.attrgetter('arg')
else:
# words that cannot be assigned to (notably
# smaller than the total keys in __builtins__)
reserved = set(['True', 'False', 'None'])
# the "id" attribute on a function node
arg_id = operator.attrgetter('id')
import _ast
util.restore__ast(_ast)
from mako import _ast_util
def parse(code, mode='exec', **exception_kwargs):
"""Parse an expression into AST"""
try:
return _ast_util.parse(code, '<unknown>', mode)
except Exception:
raise exceptions.SyntaxException(
"(%s) %s (%r)" % (
compat.exception_as().__class__.__name__,
compat.exception_as(),
code[0:50]
), **exception_kwargs)
class FindIdentifiers(_ast_util.NodeVisitor):
def __init__(self, listener, **exception_kwargs):
self.in_function = False
self.in_assign_targets = False
self.local_ident_stack = set()
self.listener = listener
self.exception_kwargs = exception_kwargs
def _add_declared(self, name):
if not self.in_function:
self.listener.declared_identifiers.add(name)
else:
self.local_ident_stack.add(name)
def visit_ClassDef(self, node):
self._add_declared(node.name)
def visit_Assign(self, node):
# flip around the visiting of Assign so the expression gets
# evaluated first, in the case of a clause like "x=x+5" (x
# is undeclared)
self.visit(node.value)
in_a = self.in_assign_targets
self.in_assign_targets = True
for n in node.targets:
self.visit(n)
self.in_assign_targets = in_a
if compat.py3k:
# ExceptHandler is in Python 2, but this block only works in
# Python 3 (and is required there)
def visit_ExceptHandler(self, node):
if node.name is not None:
self._add_declared(node.name)
if node.type is not None:
self.visit(node.type)
for statement in node.body:
self.visit(statement)
def visit_Lambda(self, node, *args):
self._visit_function(node, True)
def visit_FunctionDef(self, node):
self._add_declared(node.name)
self._visit_function(node, False)
def _expand_tuples(self, args):
for arg in args:
if isinstance(arg, _ast.Tuple):
for n in arg.elts:
yield n
else:
yield arg
def _visit_function(self, node, islambda):
# push function state onto stack. dont log any more
# identifiers as "declared" until outside of the function,
# but keep logging identifiers as "undeclared". track
# argument names in each function header so they arent
# counted as "undeclared"
inf = self.in_function
self.in_function = True
local_ident_stack = self.local_ident_stack
self.local_ident_stack = local_ident_stack.union([
arg_id(arg) for arg in self._expand_tuples(node.args.args)
])
if islambda:
self.visit(node.body)
else:
for n in node.body:
self.visit(n)
self.in_function = inf
self.local_ident_stack = local_ident_stack
def visit_For(self, node):
# flip around visit
self.visit(node.iter)
self.visit(node.target)
for statement in node.body:
self.visit(statement)
for statement in node.orelse:
self.visit(statement)
def visit_Name(self, node):
if isinstance(node.ctx, _ast.Store):
# this is eqiuvalent to visit_AssName in
# compiler
self._add_declared(node.id)
elif node.id not in reserved and node.id \
not in self.listener.declared_identifiers and node.id \
not in self.local_ident_stack:
self.listener.undeclared_identifiers.add(node.id)
def visit_Import(self, node):
for name in node.names:
if name.asname is not None:
self._add_declared(name.asname)
else:
self._add_declared(name.name.split('.')[0])
def visit_ImportFrom(self, node):
for name in node.names:
if name.asname is not None:
self._add_declared(name.asname)
else:
if name.name == '*':
raise exceptions.CompileException(
"'import *' is not supported, since all identifier "
"names must be explicitly declared. Please use the "
"form 'from <modulename> import <name1>, <name2>, "
"...' instead.", **self.exception_kwargs)
self._add_declared(name.name)
class FindTuple(_ast_util.NodeVisitor):
def __init__(self, listener, code_factory, **exception_kwargs):
self.listener = listener
self.exception_kwargs = exception_kwargs
self.code_factory = code_factory
def visit_Tuple(self, node):
for n in node.elts:
p = self.code_factory(n, **self.exception_kwargs)
self.listener.codeargs.append(p)
self.listener.args.append(ExpressionGenerator(n).value())
self.listener.declared_identifiers = \
self.listener.declared_identifiers.union(
p.declared_identifiers)
self.listener.undeclared_identifiers = \
self.listener.undeclared_identifiers.union(
p.undeclared_identifiers)
class ParseFunc(_ast_util.NodeVisitor):
def __init__(self, listener, **exception_kwargs):
self.listener = listener
self.exception_kwargs = exception_kwargs
def visit_FunctionDef(self, node):
self.listener.funcname = node.name
argnames = [arg_id(arg) for arg in node.args.args]
if node.args.vararg:
argnames.append(arg_stringname(node.args.vararg))
if compat.py2k:
# kw-only args don't exist in Python 2
kwargnames = []
else:
kwargnames = [arg_id(arg) for arg in node.args.kwonlyargs]
if node.args.kwarg:
kwargnames.append(arg_stringname(node.args.kwarg))
self.listener.argnames = argnames
self.listener.defaults = node.args.defaults # ast
self.listener.kwargnames = kwargnames
if compat.py2k:
self.listener.kwdefaults = []
else:
self.listener.kwdefaults = node.args.kw_defaults
self.listener.varargs = node.args.vararg
self.listener.kwargs = node.args.kwarg
class ExpressionGenerator(object):
def __init__(self, astnode):
self.generator = _ast_util.SourceGenerator(' ' * 4)
self.generator.visit(astnode)
def value(self):
return ''.join(self.generator.result)