Current File : //usr/lib/python3/dist-packages/mypyc/irbuild/expression.py
"""Transform mypy expression ASTs to mypyc IR (Intermediate Representation).
The top-level AST transformation logic is implemented in mypyc.irbuild.visitor
and mypyc.irbuild.builder.
"""
from typing import List, Optional, Union, Callable, cast
from mypy.nodes import (
Expression, NameExpr, MemberExpr, SuperExpr, CallExpr, UnaryExpr, OpExpr, IndexExpr,
ConditionalExpr, ComparisonExpr, IntExpr, FloatExpr, ComplexExpr, StrExpr,
BytesExpr, EllipsisExpr, ListExpr, TupleExpr, DictExpr, SetExpr, ListComprehension,
SetComprehension, DictionaryComprehension, SliceExpr, GeneratorExpr, CastExpr, StarExpr,
AssignmentExpr,
Var, RefExpr, MypyFile, TypeInfo, TypeApplication, LDEF, ARG_POS
)
from mypy.types import TupleType, Instance, TypeType, ProperType, get_proper_type
from mypyc.common import MAX_SHORT_INT
from mypyc.ir.ops import (
Value, Register, TupleGet, TupleSet, BasicBlock, Assign, LoadAddress, RaiseStandardError
)
from mypyc.ir.rtypes import (
RTuple, object_rprimitive, is_none_rprimitive, int_rprimitive, is_int_rprimitive
)
from mypyc.ir.func_ir import FUNC_CLASSMETHOD, FUNC_STATICMETHOD
from mypyc.irbuild.format_str_tokenizer import (
tokenizer_printf_style, join_formatted_strings, convert_format_expr_to_str,
convert_format_expr_to_bytes, join_formatted_bytes
)
from mypyc.primitives.bytes_ops import bytes_slice_op
from mypyc.primitives.registry import CFunctionDescription, builtin_names
from mypyc.primitives.generic_ops import iter_op
from mypyc.primitives.misc_ops import new_slice_op, ellipsis_op, type_op, get_module_dict_op
from mypyc.primitives.list_ops import list_append_op, list_extend_op, list_slice_op
from mypyc.primitives.tuple_ops import list_tuple_op, tuple_slice_op
from mypyc.primitives.dict_ops import dict_new_op, dict_set_item_op, dict_get_item_op
from mypyc.primitives.set_ops import set_add_op, set_update_op
from mypyc.primitives.str_ops import str_slice_op
from mypyc.primitives.int_ops import int_comparison_op_mapping
from mypyc.irbuild.specialize import apply_function_specialization, apply_method_specialization
from mypyc.irbuild.builder import IRBuilder
from mypyc.irbuild.for_helpers import (
translate_list_comprehension, translate_set_comprehension,
comprehension_helper
)
from mypyc.irbuild.constant_fold import constant_fold_expr
# Name and attribute references
def transform_name_expr(builder: IRBuilder, expr: NameExpr) -> Value:
if expr.node is None:
builder.add(RaiseStandardError(RaiseStandardError.RUNTIME_ERROR,
"mypyc internal error: should be unreachable",
expr.line))
return builder.none()
fullname = expr.node.fullname
if fullname in builtin_names:
typ, src = builtin_names[fullname]
return builder.add(LoadAddress(typ, src, expr.line))
# special cases
if fullname == 'builtins.None':
return builder.none()
if fullname == 'builtins.True':
return builder.true()
if fullname == 'builtins.False':
return builder.false()
if isinstance(expr.node, Var) and expr.node.is_final:
value = builder.emit_load_final(
expr.node,
fullname,
expr.name,
builder.is_native_ref_expr(expr),
builder.types[expr],
expr.line,
)
if value is not None:
return value
if isinstance(expr.node, MypyFile) and expr.node.fullname in builder.imports:
return builder.load_module(expr.node.fullname)
# If the expression is locally defined, then read the result from the corresponding
# assignment target and return it. Otherwise if the expression is a global, load it from
# the globals dictionary.
# Except for imports, that currently always happens in the global namespace.
if expr.kind == LDEF and not (isinstance(expr.node, Var)
and expr.node.is_suppressed_import):
# Try to detect and error when we hit the irritating mypy bug
# where a local variable is cast to None. (#5423)
if (isinstance(expr.node, Var) and is_none_rprimitive(builder.node_type(expr))
and expr.node.is_inferred):
builder.error(
'Local variable "{}" has inferred type None; add an annotation'.format(
expr.node.name),
expr.node.line)
# TODO: Behavior currently only defined for Var, FuncDef and MypyFile node types.
if isinstance(expr.node, MypyFile):
# Load reference to a module imported inside function from
# the modules dictionary. It would be closer to Python
# semantics to access modules imported inside functions
# via local variables, but this is tricky since the mypy
# AST doesn't include a Var node for the module. We
# instead load the module separately on each access.
mod_dict = builder.call_c(get_module_dict_op, [], expr.line)
obj = builder.call_c(dict_get_item_op,
[mod_dict, builder.load_str(expr.node.fullname)],
expr.line)
return obj
else:
return builder.read(builder.get_assignment_target(expr), expr.line)
return builder.load_global(expr)
def transform_member_expr(builder: IRBuilder, expr: MemberExpr) -> Value:
# First check if this is maybe a final attribute.
final = builder.get_final_ref(expr)
if final is not None:
fullname, final_var, native = final
value = builder.emit_load_final(final_var, fullname, final_var.name, native,
builder.types[expr], expr.line)
if value is not None:
return value
if isinstance(expr.node, MypyFile) and expr.node.fullname in builder.imports:
return builder.load_module(expr.node.fullname)
obj = builder.accept(expr.expr)
rtype = builder.node_type(expr)
# Special case: for named tuples transform attribute access to faster index access.
typ = get_proper_type(builder.types.get(expr.expr))
if isinstance(typ, TupleType) and typ.partial_fallback.type.is_named_tuple:
fields = typ.partial_fallback.type.metadata['namedtuple']['fields']
if expr.name in fields:
index = builder.builder.load_int(fields.index(expr.name))
return builder.gen_method_call(obj, '__getitem__', [index], rtype, expr.line)
check_instance_attribute_access_through_class(builder, expr, typ)
return builder.builder.get_attr(obj, expr.name, rtype, expr.line)
def check_instance_attribute_access_through_class(builder: IRBuilder,
expr: MemberExpr,
typ: Optional[ProperType]) -> None:
"""Report error if accessing an instance attribute through class object."""
if isinstance(expr.expr, RefExpr):
node = expr.expr.node
if isinstance(typ, TypeType) and isinstance(typ.item, Instance):
# TODO: Handle other item types
node = typ.item.type
if isinstance(node, TypeInfo):
class_ir = builder.mapper.type_to_ir.get(node)
if class_ir is not None and class_ir.is_ext_class:
sym = node.get(expr.name)
if (sym is not None
and isinstance(sym.node, Var)
and not sym.node.is_classvar
and not sym.node.is_final):
builder.error(
'Cannot access instance attribute "{}" through class object'.format(
expr.name),
expr.line
)
builder.note(
'(Hint: Use "x: Final = ..." or "x: ClassVar = ..." to define '
'a class attribute)',
expr.line
)
def transform_super_expr(builder: IRBuilder, o: SuperExpr) -> Value:
# warning(builder, 'can not optimize super() expression', o.line)
sup_val = builder.load_module_attr_by_fullname('builtins.super', o.line)
if o.call.args:
args = [builder.accept(arg) for arg in o.call.args]
else:
assert o.info is not None
typ = builder.load_native_type_object(o.info.fullname)
ir = builder.mapper.type_to_ir[o.info]
iter_env = iter(builder.builder.args)
# Grab first argument
vself: Value = next(iter_env)
if builder.fn_info.is_generator:
# grab sixth argument (see comment in translate_super_method_call)
self_targ = list(builder.symtables[-1].values())[6]
vself = builder.read(self_targ, builder.fn_info.fitem.line)
elif not ir.is_ext_class:
vself = next(iter_env) # second argument is self if non_extension class
args = [typ, vself]
res = builder.py_call(sup_val, args, o.line)
return builder.py_get_attr(res, o.name, o.line)
# Calls
def transform_call_expr(builder: IRBuilder, expr: CallExpr) -> Value:
if isinstance(expr.analyzed, CastExpr):
return translate_cast_expr(builder, expr.analyzed)
callee = expr.callee
if isinstance(callee, IndexExpr) and isinstance(callee.analyzed, TypeApplication):
callee = callee.analyzed.expr # Unwrap type application
if isinstance(callee, MemberExpr):
return apply_method_specialization(builder, expr, callee) or \
translate_method_call(builder, expr, callee)
elif isinstance(callee, SuperExpr):
return translate_super_method_call(builder, expr, callee)
else:
return translate_call(builder, expr, callee)
def translate_call(builder: IRBuilder, expr: CallExpr, callee: Expression) -> Value:
# The common case of calls is refexprs
if isinstance(callee, RefExpr):
return apply_function_specialization(builder, expr, callee) or \
translate_refexpr_call(builder, expr, callee)
function = builder.accept(callee)
args = [builder.accept(arg) for arg in expr.args]
return builder.py_call(function, args, expr.line,
arg_kinds=expr.arg_kinds, arg_names=expr.arg_names)
def translate_refexpr_call(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value:
"""Translate a non-method call."""
# Gen the argument values
arg_values = [builder.accept(arg) for arg in expr.args]
return builder.call_refexpr_with_args(expr, callee, arg_values)
def translate_method_call(builder: IRBuilder, expr: CallExpr, callee: MemberExpr) -> Value:
"""Generate IR for an arbitrary call of form e.m(...).
This can also deal with calls to module-level functions.
"""
if builder.is_native_ref_expr(callee):
# Call to module-level native function or such
return translate_call(builder, expr, callee)
elif (
isinstance(callee.expr, RefExpr)
and isinstance(callee.expr.node, TypeInfo)
and callee.expr.node in builder.mapper.type_to_ir
and builder.mapper.type_to_ir[callee.expr.node].has_method(callee.name)
):
# Call a method via the *class*
assert isinstance(callee.expr.node, TypeInfo)
ir = builder.mapper.type_to_ir[callee.expr.node]
decl = ir.method_decl(callee.name)
args = []
arg_kinds, arg_names = expr.arg_kinds[:], expr.arg_names[:]
# Add the class argument for class methods in extension classes
if decl.kind == FUNC_CLASSMETHOD and ir.is_ext_class:
args.append(builder.load_native_type_object(callee.expr.node.fullname))
arg_kinds.insert(0, ARG_POS)
arg_names.insert(0, None)
args += [builder.accept(arg) for arg in expr.args]
if ir.is_ext_class:
return builder.builder.call(decl, args, arg_kinds, arg_names, expr.line)
else:
obj = builder.accept(callee.expr)
return builder.gen_method_call(obj,
callee.name,
args,
builder.node_type(expr),
expr.line,
expr.arg_kinds,
expr.arg_names)
elif builder.is_module_member_expr(callee):
# Fall back to a PyCall for non-native module calls
function = builder.accept(callee)
args = [builder.accept(arg) for arg in expr.args]
return builder.py_call(function, args, expr.line,
arg_kinds=expr.arg_kinds, arg_names=expr.arg_names)
else:
receiver_typ = builder.node_type(callee.expr)
# If there is a specializer for this method name/type, try calling it.
# We would return the first successful one.
val = apply_method_specialization(builder, expr, callee, receiver_typ)
if val is not None:
return val
obj = builder.accept(callee.expr)
args = [builder.accept(arg) for arg in expr.args]
return builder.gen_method_call(obj,
callee.name,
args,
builder.node_type(expr),
expr.line,
expr.arg_kinds,
expr.arg_names)
def translate_super_method_call(builder: IRBuilder, expr: CallExpr, callee: SuperExpr) -> Value:
if callee.info is None or (len(callee.call.args) != 0 and len(callee.call.args) != 2):
return translate_call(builder, expr, callee)
# We support two-argument super but only when it is super(CurrentClass, self)
# TODO: We could support it when it is a parent class in many cases?
if len(callee.call.args) == 2:
self_arg = callee.call.args[1]
if (
not isinstance(self_arg, NameExpr)
or not isinstance(self_arg.node, Var)
or not self_arg.node.is_self
):
return translate_call(builder, expr, callee)
typ_arg = callee.call.args[0]
if (
not isinstance(typ_arg, NameExpr)
or not isinstance(typ_arg.node, TypeInfo)
or callee.info is not typ_arg.node
):
return translate_call(builder, expr, callee)
ir = builder.mapper.type_to_ir[callee.info]
# Search for the method in the mro, skipping ourselves. We
# determine targets of super calls to native methods statically.
for base in ir.mro[1:]:
if callee.name in base.method_decls:
break
else:
if (ir.is_ext_class
and ir.builtin_base is None
and not ir.inherits_python
and callee.name == '__init__'
and len(expr.args) == 0):
# Call translates to object.__init__(self), which is a
# no-op, so omit the call.
return builder.none()
return translate_call(builder, expr, callee)
decl = base.method_decl(callee.name)
arg_values = [builder.accept(arg) for arg in expr.args]
arg_kinds, arg_names = expr.arg_kinds[:], expr.arg_names[:]
if decl.kind != FUNC_STATICMETHOD:
# Grab first argument
vself: Value = builder.self()
if decl.kind == FUNC_CLASSMETHOD:
vself = builder.call_c(type_op, [vself], expr.line)
elif builder.fn_info.is_generator:
# For generator classes, the self target is the 6th value
# in the symbol table (which is an ordered dict). This is sort
# of ugly, but we can't search by name since the 'self' parameter
# could be named anything, and it doesn't get added to the
# environment indexes.
self_targ = list(builder.symtables[-1].values())[6]
vself = builder.read(self_targ, builder.fn_info.fitem.line)
arg_values.insert(0, vself)
arg_kinds.insert(0, ARG_POS)
arg_names.insert(0, None)
return builder.builder.call(decl, arg_values, arg_kinds, arg_names, expr.line)
def translate_cast_expr(builder: IRBuilder, expr: CastExpr) -> Value:
src = builder.accept(expr.expr)
target_type = builder.type_to_rtype(expr.type)
return builder.coerce(src, target_type, expr.line)
# Operators
def transform_unary_expr(builder: IRBuilder, expr: UnaryExpr) -> Value:
folded = try_constant_fold(builder, expr)
if folded:
return folded
return builder.unary_op(builder.accept(expr.expr), expr.op, expr.line)
def transform_op_expr(builder: IRBuilder, expr: OpExpr) -> Value:
if expr.op in ('and', 'or'):
return builder.shortcircuit_expr(expr)
# Special case for string formatting
if expr.op == '%' and (isinstance(expr.left, StrExpr) or isinstance(expr.left, BytesExpr)):
ret = translate_printf_style_formatting(builder, expr.left, expr.right)
if ret is not None:
return ret
folded = try_constant_fold(builder, expr)
if folded:
return folded
return builder.binary_op(
builder.accept(expr.left), builder.accept(expr.right), expr.op, expr.line
)
def transform_index_expr(builder: IRBuilder, expr: IndexExpr) -> Value:
base = builder.accept(expr.base)
index = expr.index
if isinstance(base.type, RTuple) and isinstance(index, IntExpr):
return builder.add(TupleGet(base, index.value, expr.line))
if isinstance(index, SliceExpr):
value = try_gen_slice_op(builder, base, index)
if value:
return value
index_reg = builder.accept(expr.index)
return builder.gen_method_call(
base, '__getitem__', [index_reg], builder.node_type(expr), expr.line)
def try_constant_fold(builder: IRBuilder, expr: Expression) -> Optional[Value]:
"""Return the constant value of an expression if possible.
Return None otherwise.
"""
value = constant_fold_expr(builder, expr)
if isinstance(value, int):
return builder.load_int(value)
elif isinstance(value, str):
return builder.load_str(value)
return None
def try_gen_slice_op(builder: IRBuilder, base: Value, index: SliceExpr) -> Optional[Value]:
"""Generate specialized slice op for some index expressions.
Return None if a specialized op isn't available.
This supports obj[x:y], obj[:x], and obj[x:] for a few types.
"""
if index.stride:
# We can only handle the default stride of 1.
return None
if index.begin_index:
begin_type = builder.node_type(index.begin_index)
else:
begin_type = int_rprimitive
if index.end_index:
end_type = builder.node_type(index.end_index)
else:
end_type = int_rprimitive
# Both begin and end index must be int (or missing).
if is_int_rprimitive(begin_type) and is_int_rprimitive(end_type):
if index.begin_index:
begin = builder.accept(index.begin_index)
else:
begin = builder.load_int(0)
if index.end_index:
end = builder.accept(index.end_index)
else:
# Replace missing end index with the largest short integer
# (a sequence can't be longer).
end = builder.load_int(MAX_SHORT_INT)
candidates = [list_slice_op, tuple_slice_op, str_slice_op, bytes_slice_op]
return builder.builder.matching_call_c(candidates, [base, begin, end], index.line)
return None
def transform_conditional_expr(builder: IRBuilder, expr: ConditionalExpr) -> Value:
if_body, else_body, next_block = BasicBlock(), BasicBlock(), BasicBlock()
builder.process_conditional(expr.cond, if_body, else_body)
expr_type = builder.node_type(expr)
# Having actual Phi nodes would be really nice here!
target = Register(expr_type)
builder.activate_block(if_body)
true_value = builder.accept(expr.if_expr)
true_value = builder.coerce(true_value, expr_type, expr.line)
builder.add(Assign(target, true_value))
builder.goto(next_block)
builder.activate_block(else_body)
false_value = builder.accept(expr.else_expr)
false_value = builder.coerce(false_value, expr_type, expr.line)
builder.add(Assign(target, false_value))
builder.goto(next_block)
builder.activate_block(next_block)
return target
def transform_comparison_expr(builder: IRBuilder, e: ComparisonExpr) -> Value:
# x in (...)/[...]
# x not in (...)/[...]
if (e.operators[0] in ['in', 'not in']
and len(e.operators) == 1
and isinstance(e.operands[1], (TupleExpr, ListExpr))):
items = e.operands[1].items
n_items = len(items)
# x in y -> x == y[0] or ... or x == y[n]
# x not in y -> x != y[0] and ... and x != y[n]
# 16 is arbitrarily chosen to limit code size
if 1 < n_items < 16:
if e.operators[0] == 'in':
bin_op = 'or'
cmp_op = '=='
else:
bin_op = 'and'
cmp_op = '!='
lhs = e.operands[0]
mypy_file = builder.graph['builtins'].tree
assert mypy_file is not None
bool_type = Instance(cast(TypeInfo, mypy_file.names['bool'].node), [])
exprs = []
for item in items:
expr = ComparisonExpr([cmp_op], [lhs, item])
builder.types[expr] = bool_type
exprs.append(expr)
or_expr: Expression = exprs.pop(0)
for expr in exprs:
or_expr = OpExpr(bin_op, or_expr, expr)
builder.types[or_expr] = bool_type
return builder.accept(or_expr)
# x in [y]/(y) -> x == y
# x not in [y]/(y) -> x != y
elif n_items == 1:
if e.operators[0] == 'in':
cmp_op = '=='
else:
cmp_op = '!='
e.operators = [cmp_op]
e.operands[1] = items[0]
# x in []/() -> False
# x not in []/() -> True
elif n_items == 0:
if e.operators[0] == 'in':
return builder.false()
else:
return builder.true()
# TODO: Don't produce an expression when used in conditional context
# All of the trickiness here is due to support for chained conditionals
# (`e1 < e2 > e3`, etc). `e1 < e2 > e3` is approximately equivalent to
# `e1 < e2 and e2 > e3` except that `e2` is only evaluated once.
expr_type = builder.node_type(e)
# go(i, prev) generates code for `ei opi e{i+1} op{i+1} ... en`,
# assuming that prev contains the value of `ei`.
def go(i: int, prev: Value) -> Value:
if i == len(e.operators) - 1:
return transform_basic_comparison(
builder, e.operators[i], prev, builder.accept(e.operands[i + 1]), e.line)
next = builder.accept(e.operands[i + 1])
return builder.builder.shortcircuit_helper(
'and', expr_type,
lambda: transform_basic_comparison(
builder, e.operators[i], prev, next, e.line),
lambda: go(i + 1, next),
e.line)
return go(0, builder.accept(e.operands[0]))
def transform_basic_comparison(builder: IRBuilder,
op: str,
left: Value,
right: Value,
line: int) -> Value:
if (is_int_rprimitive(left.type) and is_int_rprimitive(right.type)
and op in int_comparison_op_mapping.keys()):
return builder.compare_tagged(left, right, op, line)
negate = False
if op == 'is not':
op, negate = 'is', True
elif op == 'not in':
op, negate = 'in', True
target = builder.binary_op(left, right, op, line)
if negate:
target = builder.unary_op(target, 'not', line)
return target
def translate_printf_style_formatting(builder: IRBuilder,
format_expr: Union[StrExpr, BytesExpr],
rhs: Expression) -> Optional[Value]:
tokens = tokenizer_printf_style(format_expr.value)
if tokens is not None:
literals, format_ops = tokens
exprs = []
if isinstance(rhs, TupleExpr):
exprs = rhs.items
elif isinstance(rhs, Expression):
exprs.append(rhs)
if isinstance(format_expr, BytesExpr):
substitutions = convert_format_expr_to_bytes(builder, format_ops,
exprs, format_expr.line)
if substitutions is not None:
return join_formatted_bytes(builder, literals, substitutions, format_expr.line)
else:
substitutions = convert_format_expr_to_str(builder, format_ops,
exprs, format_expr.line)
if substitutions is not None:
return join_formatted_strings(builder, literals, substitutions, format_expr.line)
return None
# Literals
def transform_int_expr(builder: IRBuilder, expr: IntExpr) -> Value:
return builder.builder.load_int(expr.value)
def transform_float_expr(builder: IRBuilder, expr: FloatExpr) -> Value:
return builder.builder.load_float(expr.value)
def transform_complex_expr(builder: IRBuilder, expr: ComplexExpr) -> Value:
return builder.builder.load_complex(expr.value)
def transform_str_expr(builder: IRBuilder, expr: StrExpr) -> Value:
return builder.load_str(expr.value)
def transform_bytes_expr(builder: IRBuilder, expr: BytesExpr) -> Value:
return builder.load_bytes_from_str_literal(expr.value)
def transform_ellipsis(builder: IRBuilder, o: EllipsisExpr) -> Value:
return builder.add(LoadAddress(ellipsis_op.type, ellipsis_op.src, o.line))
# Display expressions
def transform_list_expr(builder: IRBuilder, expr: ListExpr) -> Value:
return _visit_list_display(builder, expr.items, expr.line)
def _visit_list_display(builder: IRBuilder, items: List[Expression], line: int) -> Value:
return _visit_display(
builder,
items,
builder.new_list_op,
list_append_op,
list_extend_op,
line,
True
)
def transform_tuple_expr(builder: IRBuilder, expr: TupleExpr) -> Value:
if any(isinstance(item, StarExpr) for item in expr.items):
# create a tuple of unknown length
return _visit_tuple_display(builder, expr)
# create a tuple of fixed length (RTuple)
tuple_type = builder.node_type(expr)
# When handling NamedTuple et. al we might not have proper type info,
# so make some up if we need it.
types = (tuple_type.types if isinstance(tuple_type, RTuple)
else [object_rprimitive] * len(expr.items))
items = []
for item_expr, item_type in zip(expr.items, types):
reg = builder.accept(item_expr)
items.append(builder.coerce(reg, item_type, item_expr.line))
return builder.add(TupleSet(items, expr.line))
def _visit_tuple_display(builder: IRBuilder, expr: TupleExpr) -> Value:
"""Create a list, then turn it into a tuple."""
val_as_list = _visit_list_display(builder, expr.items, expr.line)
return builder.call_c(list_tuple_op, [val_as_list], expr.line)
def transform_dict_expr(builder: IRBuilder, expr: DictExpr) -> Value:
"""First accepts all keys and values, then makes a dict out of them."""
key_value_pairs = []
for key_expr, value_expr in expr.items:
key = builder.accept(key_expr) if key_expr is not None else None
value = builder.accept(value_expr)
key_value_pairs.append((key, value))
return builder.builder.make_dict(key_value_pairs, expr.line)
def transform_set_expr(builder: IRBuilder, expr: SetExpr) -> Value:
return _visit_display(
builder,
expr.items,
builder.new_set_op,
set_add_op,
set_update_op,
expr.line,
False
)
def _visit_display(builder: IRBuilder,
items: List[Expression],
constructor_op: Callable[[List[Value], int], Value],
append_op: CFunctionDescription,
extend_op: CFunctionDescription,
line: int,
is_list: bool
) -> Value:
accepted_items = []
for item in items:
if isinstance(item, StarExpr):
accepted_items.append((True, builder.accept(item.expr)))
else:
accepted_items.append((False, builder.accept(item)))
result: Union[Value, None] = None
initial_items = []
for starred, value in accepted_items:
if result is None and not starred and is_list:
initial_items.append(value)
continue
if result is None:
result = constructor_op(initial_items, line)
builder.call_c(extend_op if starred else append_op, [result, value], line)
if result is None:
result = constructor_op(initial_items, line)
return result
# Comprehensions
def transform_list_comprehension(builder: IRBuilder, o: ListComprehension) -> Value:
if any(o.generator.is_async):
builder.error('async comprehensions are unimplemented', o.line)
return translate_list_comprehension(builder, o.generator)
def transform_set_comprehension(builder: IRBuilder, o: SetComprehension) -> Value:
if any(o.generator.is_async):
builder.error('async comprehensions are unimplemented', o.line)
return translate_set_comprehension(builder, o.generator)
def transform_dictionary_comprehension(builder: IRBuilder, o: DictionaryComprehension) -> Value:
if any(o.is_async):
builder.error('async comprehensions are unimplemented', o.line)
d = builder.call_c(dict_new_op, [], o.line)
loop_params = list(zip(o.indices, o.sequences, o.condlists))
def gen_inner_stmts() -> None:
k = builder.accept(o.key)
v = builder.accept(o.value)
builder.call_c(dict_set_item_op, [d, k, v], o.line)
comprehension_helper(builder, loop_params, gen_inner_stmts, o.line)
return d
# Misc
def transform_slice_expr(builder: IRBuilder, expr: SliceExpr) -> Value:
def get_arg(arg: Optional[Expression]) -> Value:
if arg is None:
return builder.none_object()
else:
return builder.accept(arg)
args = [get_arg(expr.begin_index),
get_arg(expr.end_index),
get_arg(expr.stride)]
return builder.call_c(new_slice_op, args, expr.line)
def transform_generator_expr(builder: IRBuilder, o: GeneratorExpr) -> Value:
if any(o.is_async):
builder.error('async comprehensions are unimplemented', o.line)
builder.warning('Treating generator comprehension as list', o.line)
return builder.call_c(
iter_op, [translate_list_comprehension(builder, o)], o.line
)
def transform_assignment_expr(builder: IRBuilder, o: AssignmentExpr) -> Value:
value = builder.accept(o.value)
target = builder.get_assignment_target(o.target)
builder.assign(target, value, o.line)
return value
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