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jedi-fork/jedi/evaluate/syntax_tree.py
2017-09-27 18:15:12 +02:00

258 lines
10 KiB
Python

"""
Functions evaluating the syntax tree.
"""
import copy
from parso.python import tree
from jedi import debug
from jedi import parser_utils
from jedi.evaluate.context import ContextSet, NO_CONTEXTS, ContextualizedNode, \
ContextualizedName
from jedi.evaluate import compiled
from jedi.evaluate import precedence
from jedi.evaluate import pep0484
from jedi.evaluate import recursion
from jedi.evaluate import helpers
def _limit_context_infers(func):
"""
This is for now the way how we limit type inference going wild. There are
other ways to ensure recursion limits as well. This is mostly necessary
because of instance (self) access that can be quite tricky to limit.
I'm still not sure this is the way to go, but it looks okay for now and we
can still go anther way in the future. Tests are there. ~ dave
"""
def wrapper(context, *args, **kwargs):
n = context.tree_node
evaluator = context.evaluator
try:
evaluator.inferred_element_counts[n] += 1
if evaluator.inferred_element_counts[n] > 300:
debug.warning('In context %s there were too many inferences.', n)
return NO_CONTEXTS
except KeyError:
evaluator.inferred_element_counts[n] = 1
return func(context, *args, **kwargs)
return wrapper
@debug.increase_indent
@_limit_context_infers
def eval_node(context, element):
debug.dbg('eval_element %s@%s', element, element.start_pos)
evaluator = context.evaluator
typ = element.type
if typ in ('name', 'number', 'string', 'atom'):
return eval_atom(context, element)
elif typ == 'keyword':
# For False/True/None
if element.value in ('False', 'True', 'None'):
return ContextSet(compiled.builtin_from_name(evaluator, element.value))
# else: print e.g. could be evaluated like this in Python 2.7
return NO_CONTEXTS
elif typ == 'lambdef':
from jedi.evaluate import representation as er
return ContextSet(er.FunctionContext(evaluator, context, element))
elif typ == 'expr_stmt':
return eval_expr_stmt(context, element)
elif typ in ('power', 'atom_expr'):
first_child = element.children[0]
if not (first_child.type == 'keyword' and first_child.value == 'await'):
context_set = eval_atom(context, first_child)
for trailer in element.children[1:]:
if trailer == '**': # has a power operation.
right = evaluator.eval_element(context, element.children[2])
context_set = precedence.calculate(
evaluator,
context,
context_set,
trailer,
right
)
break
context_set = eval_trailer(context, context_set, trailer)
return context_set
return NO_CONTEXTS
elif typ in ('testlist_star_expr', 'testlist',):
# The implicit tuple in statements.
from jedi.evaluate import iterable
return ContextSet(iterable.SequenceLiteralContext(evaluator, context, element))
elif typ in ('not_test', 'factor'):
context_set = context.eval_node(element.children[-1])
for operator in element.children[:-1]:
context_set = precedence.factor_calculate(evaluator, context_set, operator)
return context_set
elif typ == 'test':
# `x if foo else y` case.
return (context.eval_node(element.children[0]) |
context.eval_node(element.children[-1]))
elif typ == 'operator':
# Must be an ellipsis, other operators are not evaluated.
# In Python 2 ellipsis is coded as three single dot tokens, not
# as one token 3 dot token.
assert element.value in ('.', '...')
return ContextSet(compiled.create(evaluator, Ellipsis))
elif typ == 'dotted_name':
context_set = eval_atom(context, element.children[0])
for next_name in element.children[2::2]:
# TODO add search_global=True?
context_set = context_set.py__getattribute__(next_name, name_context=context)
return context_set
elif typ == 'eval_input':
return eval_node(context, element.children[0])
elif typ == 'annassign':
return pep0484._evaluate_for_annotation(context, element.children[1])
else:
return precedence.calculate_children(evaluator, context, element.children)
def eval_trailer(context, base_contexts, trailer):
trailer_op, node = trailer.children[:2]
if node == ')': # `arglist` is optional.
node = ()
if trailer_op == '[':
from jedi.evaluate import iterable
return iterable.py__getitem__(context.evaluator, context, base_contexts, trailer)
else:
debug.dbg('eval_trailer: %s in %s', trailer, base_contexts)
if trailer_op == '.':
return base_contexts.py__getattribute__(
name_context=context,
name_or_str=node
)
else:
assert trailer_op == '('
from jedi.evaluate import param
arguments = param.TreeArguments(context.evaluator, context, node, trailer)
return base_contexts.execute(arguments)
def eval_atom(context, atom):
"""
Basically to process ``atom`` nodes. The parser sometimes doesn't
generate the node (because it has just one child). In that case an atom
might be a name or a literal as well.
"""
from jedi.evaluate import iterable
if atom.type == 'name':
# This is the first global lookup.
stmt = tree.search_ancestor(
atom, 'expr_stmt', 'lambdef'
) or atom
if stmt.type == 'lambdef':
stmt = atom
return context.py__getattribute__(
name_or_str=atom,
position=stmt.start_pos,
search_global=True
)
elif isinstance(atom, tree.Literal):
string = parser_utils.safe_literal_eval(atom.value)
return ContextSet(compiled.create(context.evaluator, string))
else:
c = atom.children
if c[0].type == 'string':
# Will be one string.
context_set = eval_atom(context, c[0])
for string in c[1:]:
right = eval_atom(context, string)
context_set = precedence.calculate(context.evaluator, context, context_set, '+', right)
return context_set
# Parentheses without commas are not tuples.
elif c[0] == '(' and not len(c) == 2 \
and not(c[1].type == 'testlist_comp' and
len(c[1].children) > 1):
return context.eval_node(c[1])
try:
comp_for = c[1].children[1]
except (IndexError, AttributeError):
pass
else:
if comp_for == ':':
# Dict comprehensions have a colon at the 3rd index.
try:
comp_for = c[1].children[3]
except IndexError:
pass
if comp_for.type == 'comp_for':
return ContextSet(iterable.Comprehension.from_atom(context.evaluator, context, atom))
# It's a dict/list/tuple literal.
array_node = c[1]
try:
array_node_c = array_node.children
except AttributeError:
array_node_c = []
if c[0] == '{' and (array_node == '}' or ':' in array_node_c):
context = iterable.DictLiteralContext(context.evaluator, context, atom)
else:
context = iterable.SequenceLiteralContext(context.evaluator, context, atom)
return ContextSet(context)
@_limit_context_infers
def eval_expr_stmt(context, stmt, seek_name=None):
with recursion.execution_allowed(context.evaluator, stmt) as allowed:
if allowed or context.get_root_context() == context.evaluator.BUILTINS:
return _eval_expr_stmt(context, stmt, seek_name)
return NO_CONTEXTS
@debug.increase_indent
def _eval_expr_stmt(context, stmt, seek_name=None):
"""
The starting point of the completion. A statement always owns a call
list, which are the calls, that a statement does. In case multiple
names are defined in the statement, `seek_name` returns the result for
this name.
:param stmt: A `tree.ExprStmt`.
"""
debug.dbg('eval_expr_stmt %s (%s)', stmt, seek_name)
rhs = stmt.get_rhs()
context_set = context.eval_node(rhs)
if seek_name:
c_node = ContextualizedName(context, seek_name)
from jedi.evaluate import finder
context_set = finder.check_tuple_assignments(context.evaluator, c_node, context_set)
first_operator = next(stmt.yield_operators(), None)
if first_operator not in ('=', None) and first_operator.type == 'operator':
# `=` is always the last character in aug assignments -> -1
operator = copy.copy(first_operator)
operator.value = operator.value[:-1]
name = stmt.get_defined_names()[0].value
left = context.py__getattribute__(
name, position=stmt.start_pos, search_global=True)
for_stmt = tree.search_ancestor(stmt, 'for_stmt')
if for_stmt is not None and for_stmt.type == 'for_stmt' and context_set \
and parser_utils.for_stmt_defines_one_name(for_stmt):
# Iterate through result and add the values, that's possible
# only in for loops without clutter, because they are
# predictable. Also only do it, if the variable is not a tuple.
node = for_stmt.get_testlist()
cn = ContextualizedNode(context, node)
from jedi.evaluate import iterable
ordered = list(iterable.py__iter__(context.evaluator, cn.infer(), cn))
for lazy_context in ordered:
dct = {for_stmt.children[1].value: lazy_context.infer()}
with helpers.predefine_names(context, for_stmt, dct):
t = context.eval_node(rhs)
left = precedence.calculate(context.evaluator, context, left, operator, t)
context_set = left
else:
context_set = precedence.calculate(context.evaluator, context, left, operator, context_set)
debug.dbg('eval_expr_stmt result %s', context_set)
return context_set