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Copy pathast.py
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1505 lines (1354 loc) · 54.3 KB
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from blib2to3.pgen2 import token
from ast import literal_eval
from semmle.python import ast
from semmle.util import get_analysis_major_version
from blib2to3.pgen2.parse import ParseError
import sys
LOAD = ast.Load()
STORE = ast.Store()
PARAM = ast.Param()
DEL = ast.Del()
POSITIONAL = 1
KEYWORD = 2
class ParseTreeVisitor(object):
'''Standard tree-walking visitor,
using `node.name` rather than `type(node).__name__`
'''
def visit(self, node, extra_arg=None):
method = 'visit_' + node.name
if extra_arg is None:
return getattr(self, method)(node)
else:
return getattr(self, method)(node, extra_arg)
class Convertor(ParseTreeVisitor):
''' Walk the conrete parse tree, returning an AST.
The CPT is specified by blib2to3/Grammar.txt.
The AST specified by semmle/python/master.py.
Each `visit_X` method takes a `X` node in the CFG and
produces some part of the AST, usually a single node.
'''
def __init__(self, logger):
self.logger = logger
# To handle f-strings nested inside other f-strings, we must keep track of the stack of
# surrounding prefixes while walking the tree. This is necessary because inside an f-string
# like `f"hello{f'to{you}dear'}world"`, the string part containing "world" has (in terms of
# the concrete parse tree) a prefix of `}`, which doesn't tell us how to interpret it (in
# particular, we can't tell if it's a raw string or not). So instead we look at the top of
# the prefix stack to figure out what the "current prefix" is. The nested f-string in the
# example above demonstrates why we must do this as a stack -- we must restore the outer
# `f"` prefix when we're done with the inner `f'`-prefix string.
#
# The stack manipulation itself takes place in the `visit_FSTRING_START` and
# `visit_FSTRING_END` methods. The text wrangling takes place in the `parse_string` helper
# function.
self.outer_prefix_stack = []
def visit_file_input(self, node):
body = []
for s in [self.visit(s) for s in node.children if s.name not in ("ENDMARKER", "NEWLINE")]:
if isinstance(s, list):
body.extend(s)
else:
body.append(s)
result = ast.Module(body)
set_location(result, node)
return result
def visit_import_from(self, node):
level = 0
index = 1
module_start = node.children[index].start
while is_token(node.children[index], "."):
level += 1
index += 1
if is_token(node.children[index], "import"):
module_end = node.children[index-1].end
index += 1
module_name = None
else:
module_end = node.children[index].end
module_name = self.visit(node.children[index])
index += 2
if is_token(node.children[index], "*"):
module = ast.ImportExpr(level, module_name, False)
set_location(module, module_start, module_end)
result = ast.ImportFrom(module)
set_location(result, node)
return result
if is_token(node.children[index], "("):
import_as_names = node.children[index+1]
else:
import_as_names = node.children[index]
aliases = []
for import_as_name in import_as_names.children[::2]:
module = ast.ImportExpr(level, module_name, False)
set_location(module, module_start, module_end)
aliases.append(self._import_as_name(import_as_name, module))
result = ast.Import(aliases)
set_location(result, node)
return result
#Helper for visit_import_from
def _import_as_name(self, node, module):
name = node.children[0].value
if len(node.children) == 3:
asname = node.children[2]
else:
asname = node.children[0]
expr = ast.ImportMember(module, name)
set_location(expr, node)
rhs = make_name(asname.value, STORE, asname.start, asname.end)
result = ast.alias(expr, rhs)
set_location(result, node)
return result
def visit_small_stmt(self, node):
return self.visit(node.children[0])
def visit_simple_stmt(self, node):
return [self.visit(s) for s in node.children if s.name not in ("SEMI", "NEWLINE")]
def visit_stmt(self, node):
return self.visit(node.children[0])
def visit_compound_stmt(self, node):
return self.visit(node.children[0])
def visit_pass_stmt(self, node):
p = ast.Pass()
set_location(p, node)
return p
def visit_classdef(self, node):
if len(node.children) == 4:
cls, name, colon, suite = node.children
args, keywords = [], []
elif len(node.children) == 7:
cls, name, _, args, _, colon, suite = node.children
args, keywords = self.visit(args)
else:
assert len(node.children) == 6
cls, name, _, _, colon, suite = node.children
args, keywords = [], []
start = cls.start
end = colon.end
suite = self.visit(suite)
inner = ast.Class(name.value, suite)
set_location(inner, start, end)
cls_expr = ast.ClassExpr(name.value, [], args, keywords, inner)
set_location(cls_expr, start, end)
name_expr = make_name(name.value, STORE, name.start, name.end)
result = ast.Assign(cls_expr, [name_expr])
set_location(result, start, end)
return result
def visit_arglist(self, node):
all_args = self._visit_list(node.children[::2])
args = [ arg for kind, arg in all_args if kind is POSITIONAL ]
keywords = [ arg for kind, arg in all_args if kind is KEYWORD ]
return args, keywords
def visit_argument(self, node):
child = node.children[0]
if is_token(child, "*"):
kind, arg = POSITIONAL, ast.Starred(self.visit(node.children[1], LOAD), LOAD)
elif is_token(child, "**"):
kind, arg = KEYWORD, ast.DictUnpacking(self.visit(node.children[1], LOAD))
elif len(node.children) == 3 and is_token(node.children[1], "="):
try:
name = get_node_value(child)
except Exception:
#Not a legal name
name = None
self.logger.warning("Illegal name for keyword on line %s", child.start[0])
kind, arg = KEYWORD, ast.keyword(name, self.visit(node.children[2], LOAD))
else:
arg = self.visit(child, LOAD)
if len(node.children) == 1:
return POSITIONAL, arg
elif len(node.children) == 3 and is_token(node.children[1], ":="):
return POSITIONAL, self.visit_namedexpr_test(node, LOAD)
generators = self.visit(node.children[1])
kind, arg = POSITIONAL, ast.GeneratorExp(arg, generators)
set_location(arg, node)
rewrite_comp(arg)
set_location(arg, node)
return kind, arg
def visit_namedexpr_test(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
target = self.visit(node.children[0], STORE)
value = self.visit(node.children[-1], LOAD)
result = ast.AssignExpr(value, target)
set_location(result, node)
return result
def visit_test(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
else:
if ctx is not LOAD:
context_error(node)
body = self.visit(node.children[0], ctx)
test = self.visit(node.children[2], ctx)
orelse = self.visit(node.children[4], ctx)
ifexp = ast.IfExp(test, body, orelse)
set_location(ifexp, node)
return ifexp
def visit_or_test(self, node, ctx):
return self._boolop(node, ast.Or, ctx)
def visit_and_test(self, node, ctx):
return self._boolop(node, ast.And, ctx)
def visit_not_test(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
if ctx is not LOAD:
context_error(node)
result = ast.UnaryOp(
ast.Not(),
self.visit(node.children[1], ctx)
)
set_location(result, node)
return result
# Helper for `or` and `and`.
def _boolop(self, node, opcls, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
values = [ self.visit(s, ctx) for s in node.children[::2] ]
result = ast.BoolOp(opcls(), values)
set_location(result, node)
return result
# Helper for various binary expression visitors.
def _binary(self, node, opfact, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
if ctx is not LOAD:
context_error(node)
children = iter(node.children)
result = self.visit(next(children), LOAD)
for op in children:
item = next(children)
rhs = self.visit(item, LOAD)
result = ast.BinOp(result, opfact(op), rhs)
set_location(result, node.start, item.end)
return result
def visit_suite(self, node):
if len(node.children) == 1:
return self.visit(node.children[0])
result = []
for s in [self.visit(s) for s in node.children[2:-1]]:
if isinstance(s, list):
result.extend(s)
else:
result.append(s)
return result
def visit_expr_stmt(self, node):
if len(node.children) == 1:
result = ast.Expr(self.visit(node.children[0], LOAD))
set_location(result, node)
return result
if len(node.children) > 1 and is_token(node.children[1], "="):
return self._assign(node)
if len(node.children) == 2:
# Annotated assignment
target = self.visit(node.children[0], STORE)
ann = node.children[1]
type_anno = self.visit(ann.children[1], LOAD)
if len(ann.children) > 2:
value = self.visit(ann.children[3], LOAD)
else:
value = None
result = ast.AnnAssign(value, type_anno, target)
else:
#Augmented assignment
lhs = self.visit(node.children[0], LOAD)
op = self.visit(node.children[1])
rhs = self.visit(node.children[2], LOAD)
expr = ast.BinOp(lhs, op, rhs)
set_location(expr, node)
result = ast.AugAssign(expr)
set_location(result, node)
return result
def visit_augassign(self, node):
return AUG_ASSIGN_OPS[node.children[0].value]()
#Helper for visit_expr_stmt (for assignment)
def _assign(self, node):
targets = [ self.visit(t, STORE) for t in node.children[:-1:2]]
result = ast.Assign(self.visit(node.children[-1], LOAD), targets)
set_location(result, node)
return result
def visit_testlist(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
elts = self._visit_list(node.children[::2], ctx)
result = ast.Tuple(elts, ctx)
set_location(result, node)
return result
visit_testlist_star_expr = visit_testlist
def visit_comparison(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
if ctx is not LOAD:
context_error(node)
left = self.visit(node.children[0], ctx)
ops = [ self.visit(op) for op in node.children[1::2]]
comps = [ self.visit(op, ctx) for op in node.children[2::2]]
result = ast.Compare(left, ops, comps)
set_location(result, node)
return result
def visit_comp_op(self, node):
if len(node.children) == 1:
return COMP_OP_CLASSES[node.children[0].value]()
else:
assert len(node.children) == 2
return ast.IsNot() if node.children[0].value == "is" else ast.NotIn()
def visit_expr(self, node, ctx):
return self._binary(node, lambda _: ast.BitOr(), ctx)
def visit_xor_expr(self, node, ctx):
return self._binary(node, lambda _: ast.BitXor(), ctx)
def visit_and_expr(self, node, ctx):
return self._binary(node, lambda _: ast.BitAnd(), ctx)
def visit_shift_expr(self, node, ctx):
return self._binary(
node,
lambda op: ast.LShift() if op.value == "<<" else ast.RShift(),
ctx
)
def visit_arith_expr(self, node, ctx):
return self._binary(
node,
lambda op: ast.Add() if op.value == "+" else ast.Sub(),
ctx
)
def visit_term(self, node, ctx):
return self._binary(
node,
lambda op: TERM_OP_CLASSES[op.value](),
ctx
)
def visit_factor(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
result = ast.UnaryOp(
FACTOR_OP_CLASSES[node.children[0].value](),
self.visit(node.children[1], ctx)
)
set_location(result, node)
return result
def visit_power(self, node, ctx):
'''This part of the Grammar is formulated in a slightly
awkward way, so we need to recursively handle the `await`
prefix, then the `** factor` suffix, then the atom and trailers.
'''
# Because `await` was a valid identifier in earlier versions of Python,
# we cannot assume it indicates an `await` expression. We therefore
# have to look at what follows in order to make a decision. The
# relevant part of the grammar is
#
# power: ['await'] atom trailer* ['**' factor]
#
# The case we wish to identify is when 'await' appears, but as an
# `atom`, and not an `await` token.
#
# Because `atom` nodes may no longer be present (see
# `SKIP_IF_SINGLE_CHILD_NAMES` in `__init__.py`) we instead look at the
# node following the (potentially) skipped `atom`. In particular, if
# the following node is a `trailer` or "**" token, we know that the
# given node cannot be an `await` token, and must be an `atom` instead.
try:
next_node = node.children[1]
next_is_atom = next_node.name != "trailer" and not is_token(next_node, "**")
except (IndexError, AttributeError):
# IndexError if `node` has at most one child.
# AttributeError if `next_node` is a `Leaf` instead of a `Node`.
next_is_atom = False
if is_token(node.children[0], "await") and next_is_atom:
if ctx is not LOAD:
context_error(node)
pow = self._power(node.children[1:], ctx)
result = ast.Await(pow)
set_location(result, node)
return result
else:
return self._power(node.children, ctx)
#Helper for visit_power
def _power(self, children, ctx):
start = children[0].start
if len(children) > 1 and is_token(children[-2], "**"):
if ctx is not LOAD:
context_error(children[0])
trailers = children[1:-2]
pow_expr = self.visit(children[-1], ctx)
else:
trailers = children[1:]
pow_expr = None
if trailers:
expr = self.visit(children[0], LOAD)
for trailer in trailers[:-1]:
expr = self._apply_trailer(expr, trailer, start, LOAD)
expr = self._apply_trailer(expr, trailers[-1], start, ctx)
else:
expr = self.visit(children[0], ctx)
if pow_expr:
expr = ast.BinOp(expr, ast.Pow(), pow_expr)
set_location(expr, children[0].start, children[-1].end)
return expr
#Helper for _power
def _atom(self, children, ctx):
start = children[0].start
if len(children) == 1:
return self.visit(children[0], ctx)
atom = self.visit(children[0], LOAD)
for trailer in children[1:-1]:
atom = self._apply_trailer(atom, trailer, start, LOAD)
atom = self._apply_trailer(atom, children[-1], start, ctx)
return atom
#Helper for _atom
def _apply_trailer(self, atom, trailer, start, ctx):
children = trailer.children
left = children[0]
if is_token(left, "("):
if is_token(children[1], ")"):
args, keywords = [], []
end = children[1].end
else:
args, keywords = self.visit(children[1])
end = children[2].end
result = ast.Call(atom, args, keywords)
elif is_token(left, "["):
result = ast.Subscript(atom, self.visit(children[1], LOAD), ctx)
end = children[2].end
else:
assert is_token(left, ".")
result = ast.Attribute(atom, children[1].value, ctx)
end = children[1].end
set_location(result, start, end)
return result
def visit_atom(self, node, ctx):
left = node.children[0]
if left.value in "[({":
n = node.children[1]
if hasattr(n, "value") and n.value in "])}":
if n.value == ")":
result = ast.Tuple([], ctx)
elif n.value == "]":
result = ast.List([], ctx)
else:
result = ast.Dict([])
set_location(result, node)
return result
else:
result = self.visit(node.children[1], ctx)
if left.value == "(":
result.parenthesised = True
else:
#Meaningful bracketing
set_location(result, node)
if isinstance(result, (ast.GeneratorExp, ast.ListComp, ast.SetComp, ast.DictComp)):
rewrite_comp(result)
return result
if left.type == token.NAME:
return make_name(left.value, ctx, left.start, left.end)
if ctx is not LOAD:
context_error(node)
if left.type == token.NUMBER:
val = get_numeric_value(left)
result = ast.Num(val, left.value)
set_location(result, left)
return result
if left.value == ".":
assert len(node.children) == 3 and node.children[2].value == "."
result = ast.Ellipsis()
set_location(result, node)
return result
assert left.type == token.BACKQUOTE
result = ast.Repr(self.visit(node.children[1], LOAD))
set_location(result, node)
return result
def visit_STRING(self, node, ctx):
if ctx is not LOAD:
context_error(node)
outer_prefix = self.outer_prefix_stack[-1] if self.outer_prefix_stack else None
prefix, s = parse_string(node.value, self.logger, outer_prefix)
text = get_text(node.value, outer_prefix)
result = ast.StringPart(prefix, text, s)
set_location(result, node)
return result
def visit_NUMBER(self, node, ctx):
if ctx is not LOAD:
context_error(node)
val = get_numeric_value(node)
result = ast.Num(val, node.value)
set_location(result, node)
return result
def visit_funcdef(self, node, is_async=False):
# funcdef: 'def' NAME parameters ['->' test] ':' suite
name = node.children[1].value
if node.children[3].value == "->":
return_type = self.visit(node.children[4], LOAD)
end = node.children[5].end
body = self.visit(node.children[6])
else:
return_type = None
end = node.children[3].end
body = self.visit(node.children[4])
start = node.children[0].start
params = node.children[2]
if len(params.children) == 2:
args, vararg, kwonlyargs, kwarg = [], None, [], None
else:
args, vararg, kwonlyargs, kwarg = self._get_parameters(params.children[1])
func = ast.Function(name, [], args, vararg, kwonlyargs, kwarg, body, is_async)
set_location(func, start, end)
if len(params.children) == 2:
args = ast.arguments([], [], [], None, None, [])
else:
args = self._get_defaults_and_annotations(params.children[1])
funcexpr = ast.FunctionExpr(name, args, return_type, func)
set_location(funcexpr, start, end)
name_expr = make_name(name, STORE, node.children[1].start, node.children[1].end)
result = ast.Assign(funcexpr, [name_expr])
set_location(result, start, end)
return result
#Helper for visit_funcdef and visit_lambdef
def _get_parameters(self, node):
'''Returns the quadruple: args, vararg, kwonlyargs, kwarg
'''
args = []
vararg = None
kwonlyargs = []
kwarg = None
children = iter(node.children)
arg = None
for child in children:
if is_token(child, "*"):
try:
child = next(children)
except StopIteration:
pass
else:
if not is_token(child, ","):
vararg = self.visit(child, PARAM)
break
if is_token(child, ","):
pass
elif is_token(child, "/"):
pass
elif is_token(child, "="):
next(children)
elif is_token(child, "**"):
child = next(children)
kwarg = self.visit(child, PARAM)
else:
arg = self.visit(child, PARAM)
args.append(arg)
#kwonly args
for child in children:
if is_token(child, ","):
pass
elif is_token(child, "="):
next(children)
elif is_token(child, "**"):
child = next(children)
kwarg = self.visit(child, PARAM)
else:
arg = self.visit(child, PARAM)
kwonlyargs.append(arg)
return args, vararg, kwonlyargs, kwarg
#Helper for visit_funcdef and visit_lambdef
def _get_defaults_and_annotations(self, node):
defaults = []
kw_defaults = []
annotations = []
varargannotation = None
kwargannotation = None
kw_annotations = []
children = iter(node.children)
# Because we want the i'th element of `kw_defaults` to be the default value for
# the i'th keyword-only argument, when encountering the combined token for the
# argument name and optional annotation, we add a `None` to `kw_defaults` assuming
# that there is no default value. If there turns out to be a default value, we
# remove the `None` and add the real default value. Like-wise for `defaults`.
# positional-only args and "normal" args
for child in children:
if is_token(child, "*"):
try:
child = next(children)
except StopIteration:
pass
else:
if not is_token(child, ","):
varargannotation = self.visit(child, LOAD)
break
if is_token(child, ","):
pass
elif is_token(child, "/"):
pass
elif is_token(child, "="):
child = next(children)
defaults.pop()
defaults.append(self.visit(child, LOAD))
elif is_token(child, "**"):
child = next(children)
kwargannotation = self.visit(child, LOAD)
arg = None
else:
# Preemptively assume there is no default argument (indicated by None)
defaults.append(None)
annotations.append(self.visit(child, LOAD))
#kwonly args
for child in children:
if is_token(child, ","):
pass
elif is_token(child, "="):
child = next(children)
kw_defaults.pop()
kw_defaults.append(self.visit(child, LOAD))
elif is_token(child, "**"):
child = next(children)
kwargannotation = self.visit(child, LOAD)
else:
# Preemptively assume there is no default argument (indicated by None)
kw_defaults.append(None)
kw_annotations.append(self.visit(child, LOAD))
result = ast.arguments(defaults, kw_defaults, annotations, varargannotation, kwargannotation, kw_annotations)
set_location(result, node)
return result
def visit_tfpdef(self, node, ctx):
# TO DO Support tuple parameters
# No one uses them any more, so this isn't super important.
child = node.children[0]
if is_token(child, "("):
return None
return self.visit(child, ctx)
def visit_tname(self, node, ctx):
if ctx is PARAM:
child = node.children[0]
return make_name(child.value, ctx, child.start, child.end)
elif len(node.children) > 1:
return self.visit(node.children[2], ctx)
else:
return None
def visit_decorated(self, node):
asgn = self.visit(node.children[1])
value = asgn.value
for deco in reversed(node.children[0].children):
defn = value
decorator = self.visit(deco)
value = ast.Call(decorator, [defn], [])
copy_location(decorator, value)
asgn.value = value
return asgn
def visit_decorators(self, node):
return self._visit_list(node.children)
def visit_decorator(self, node):
namedexpr_test = node.children[1]
result = self.visit_namedexpr_test(namedexpr_test, LOAD)
set_location(result, namedexpr_test)
return result
def _visit_list(self, items, ctx=None):
if ctx is None:
return [ self.visit(i) for i in items ]
else:
return [ self.visit(i, ctx) for i in items ]
def visit_dotted_name(self, node):
return ".".join(name.value for name in node.children[::2])
def visit_NAME(self, name, ctx):
return make_name(name.value, ctx, name.start, name.end)
def visit_listmaker(self, node, ctx):
if len(node.children) == 1 or is_token(node.children[1], ","):
items = [self.visit(c, ctx) for c in node.children[::2]]
result = ast.List(items, ctx)
else:
if ctx is not LOAD:
context_error(node)
elt = self.visit(node.children[0], ctx)
generators = self.visit(node.children[1])
result = ast.ListComp(elt, generators)
set_location(result, node)
return result
def visit_testlist_gexp(self, node, ctx):
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
if is_token(node.children[1], ","):
items = [self.visit(c, ctx) for c in node.children[::2]]
result = ast.Tuple(items, ctx)
else:
if ctx is not LOAD:
context_error(node)
elt = self.visit(node.children[0], ctx)
generators = self.visit(node.children[1])
result = ast.GeneratorExp(elt, generators)
set_location(result, node)
return result
def visit_comp_for(self, node):
is_async = is_token(node.children[0], "async")
target = self.visit(node.children[1+is_async], STORE)
iter = self.visit(node.children[3+is_async], LOAD)
if len(node.children) == 5+is_async:
ifs = []
end = iter._end
comp_iter = self.visit(node.children[4+is_async])
while comp_iter and not isinstance(comp_iter[0], ast.comprehension):
ifs.append(comp_iter[0])
end = comp_iter[0]._end
comp_iter = comp_iter[1:]
comp = ast.comprehension(target, iter, ifs)
comp.is_async = is_async
set_location(comp, node.children[0].start, end)
return [comp] + comp_iter
else:
comp = ast.comprehension(target, iter, [])
comp.is_async = is_async
set_location(comp, node)
return [comp]
visit_old_comp_for = visit_comp_for
def visit_comp_iter(self, node):
return self.visit(node.children[0])
def visit_comp_if(self, node):
cond = self.visit(node.children[1], LOAD)
if len(node.children) == 3:
comp_list = self.visit(node.children[2])
return [cond] + comp_list
else:
return [cond]
visit_old_comp_if = visit_comp_if
visit_old_comp_iter = visit_comp_iter
def visit_exprlist(self, node, ctx):
#Despite the name this returns a single expression
if len(node.children) == 1:
return self.visit(node.children[0], ctx)
else:
elts = self._visit_list(node.children[::2], ctx)
result = ast.Tuple(elts, ctx)
set_location(result, node)
return result
visit_testlist_safe = visit_exprlist
def visit_old_test(self, node, ctx):
return self.visit(node.children[0], ctx)
def visit_if_stmt(self, node):
endindex = len(node.children)
if is_token(node.children[-3], "else"):
orelse = self.visit(node.children[-1])
endindex -= 3
else:
orelse = None
while endindex:
test = self.visit(node.children[endindex-3], LOAD)
body = self.visit(node.children[endindex-1])
result = ast.If(test, body, orelse)
start = node.children[endindex-4].start
end = node.children[endindex-2].end
set_location(result, start, end)
orelse = [result]
endindex -= 4
return result
def visit_import_stmt(self, node):
return self.visit(node.children[0])
def visit_import_name(self, node):
aliases = self.visit(node.children[1])
result = ast.Import(aliases)
set_location(result, node)
return result
def visit_dotted_as_names(self, node):
return self._visit_list(node.children[::2])
def visit_dotted_as_name(self, node):
child0 = node.children[0]
dotted_name = self.visit(child0)
if len(node.children) == 3:
value = ast.ImportExpr(0, dotted_name, False)
child2 = node.children[2]
asname = make_name(child2.value, STORE, child2.start, child2.end)
else:
value = ast.ImportExpr(0, dotted_name, True)
topname = dotted_name.split(".")[0]
asname = make_name(topname, STORE, child0.start, child0.end)
set_location(value, child0)
result = ast.alias(value, asname)
set_location(result, node)
return result
def visit_dictsetmaker(self, node, ctx):
if ctx is not LOAD:
context_error(node)
if is_token(node.children[0], "**") or len(node.children) > 1 and is_token(node.children[1], ":"):
return self._dictmaker(node)
else:
return self._setmaker(node)
#Helper for visit_dictsetmaker (for dictionaries)
def _dictmaker(self, node):
if len(node.children) == 4 and is_token(node.children[1], ":") and not is_token(node.children[3], ","):
#Comprehension form
key = self.visit(node.children[0], LOAD)
value = self.visit(node.children[2], LOAD)
generators = self.visit(node.children[3])
result = ast.DictComp(key, value, generators)
set_location(result, node)
return result
index = 0
items = []
while len(node.children) > index:
if is_token(node.children[index], "**"):
d = self.visit(node.children[index+1], LOAD)
item = ast.DictUnpacking(d)
set_location(item, node.children[index].start, node.children[index+1].end)
index += 3
else:
key = self.visit(node.children[index], LOAD)
value = self.visit(node.children[index+2], LOAD)
item = ast.KeyValuePair(key, value)
set_location(item, node.children[index].start, node.children[index+2].end)
index += 4
items.append(item)
result = ast.Dict(items)
set_location(result, node)
return result
#Helper for visit_dictsetmaker (for sets)
def _setmaker(self, node):
if len(node.children) == 2 and not is_token(node.children[1], ","):
#Comprehension form
elt = self.visit(node.children[0], LOAD)
generators = self.visit(node.children[1])
result = ast.SetComp(elt, generators)
set_location(result, node)
return result
items = self._visit_list(node.children[::2], LOAD)
result = ast.Set(items)
set_location(result, node)
return result
def visit_while_stmt(self, node):
test = self.visit(node.children[1], LOAD)
body = self.visit(node.children[3])
if len(node.children) == 7:
orelse = self.visit(node.children[6])
else:
orelse = None
result = ast.While(test, body, orelse)
set_location(result, node.children[0].start, node.children[2].end)
return result
def visit_flow_stmt(self, node):
return self.visit(node.children[0])
def visit_break_stmt(self, node):
result = ast.Break()
set_location(result, node)
return result
def visit_continue_stmt(self, node):
result = ast.Continue()
set_location(result, node)
return result
def visit_return_stmt(self, node):
if len(node.children) == 2:
result = ast.Return(self.visit(node.children[1], LOAD))
else:
result = ast.Return(None)
set_location(result, node)
return result
def visit_raise_stmt(self, node):
result = ast.Raise()
set_location(result, node)
if len(node.children) == 1:
return result
result.exc = self.visit(node.children[1], LOAD)
if len(node.children) > 3:
if is_token(node.children[2], "from"):
result.cause = self.visit(node.children[3], LOAD)
else:
result.type = result.exc
del result.exc
result.inst = self.visit(node.children[3], LOAD)
if len(node.children) == 6:
result.tback = self.visit(node.children[5], LOAD)
return result
def visit_yield_stmt(self, node):
result = ast.Expr(self.visit(node.children[0], LOAD))
set_location(result, node)
return result
def visit_yield_expr(self, node, ctx):
if ctx is not LOAD:
context_error(node)
if len(node.children) == 1:
result = ast.Yield(None)
else:
if is_token(node.children[1].children[0], "from"):
result = ast.YieldFrom(self.visit(node.children[1].children[1], LOAD))
else:
result = ast.Yield(self.visit(node.children[1].children[0], LOAD))
set_location(result, node)
return result
def visit_try_stmt(self, node):
body = self.visit(node.children[2])
index = 3
handlers = []
while len(node.children) > index and not hasattr(node.children[index], "value"):
#Except block.
type, name = self.visit(node.children[index])
handler_body = self.visit(node.children[index+2])
handler = ast.ExceptStmt(type, name, handler_body)
set_location(handler, node.children[index].start , node.children[index+1].end)
handlers.append(handler)
index += 3
if len(node.children) > index and is_token(node.children[index], "else"):
orelse = self.visit(node.children[index+2])
else:
orelse = []
if is_token(node.children[-3], "finally"):
finalbody = self.visit(node.children[-1])
else:
finalbody = []
result = ast.Try(body, orelse, handlers, finalbody)
set_location(result, node.start, node.children[1].end)
return result
def visit_except_clause(self, node):
type, name = None, None
if len(node.children) > 1:
type = self.visit(node.children[1], LOAD)
if len(node.children) > 3:
# The grammar rule `'except' [test [(',' | 'as') test]]` is shared
# between two incompatible readings of a fourth child, so the
# separator token and the analysis version together decide:
# `except A as e:` binds an alias, in every version;
# `except A, e:` binds an alias when extracting Python 2, where
# that is the canonical idiom;
# `except A, B:` is an unparenthesized tuple of exception types
# otherwise -- PEP 758, Python 3.14+.
if is_token(node.children[2], "as") or get_analysis_major_version() == 2:
name = self.visit(node.children[3], STORE)
else:
elts = [type, self.visit(node.children[3], LOAD)]
type = ast.Tuple(elts, LOAD)
set_location(type, node.children[1].start, node.children[3].end)
return type, name