def unpackFrom(source, arg_names):
accesses = []
sub_special_index = 0
iter_var = outer_body.allocateTempVariable(
None, "arg_iter_%d" % len(iter_vars))
iter_vars.append(iter_var)
statements.append(
StatementAssignmentVariable(
variable_ref=ExpressionTargetTempVariableRef(
variable=iter_var, source_ref=source_ref),
source=ExpressionBuiltinIter1(value=source,
source_ref=source_ref),
source_ref=source_ref))
for element_index, arg_name in enumerate(arg_names):
if getKind(arg_name) == "Name":
inner_arg_names.append(arg_name.id)
arg_var = outer_body.allocateTempVariable(
None, "tmp_" + arg_name.id)
statements.append(
StatementAssignmentVariable(
variable_ref=ExpressionTargetTempVariableRef(
variable=arg_var, source_ref=source_ref),
source=ExpressionSpecialUnpack(
value=ExpressionTempVariableRef(
variable=iter_var, source_ref=source_ref),
count=element_index + 1,
expected=len(arg_names),
source_ref=source_ref),
source_ref=source_ref))
accesses.append(
ExpressionTempVariableRef(variable=arg_var,
source_ref=source_ref))
elif getKind(arg_name) == "Tuple":
accesses.extend(
unpackFrom(source=ExpressionSpecialUnpack(
value=ExpressionTempVariableRef(
variable=iter_var, source_ref=source_ref),
count=element_index + 1,
expected=len(arg_names),
source_ref=source_ref),
arg_names=arg_name.elts))
sub_special_index += 1
else:
assert False, arg_name
statements.append(
StatementSpecialUnpackCheck(iterator=ExpressionTempVariableRef(
variable=iter_var, source_ref=source_ref),
count=len(arg_names),
source_ref=source_ref))
return accesses
def buildAssignmentStatementsFromDecoded(provider, kind, detail, source,
source_ref):
# This is using many variable names on purpose, so as to give names to the
# unpacked detail values, and has many branches due to the many cases
# dealt with, pylint: disable=too-many-branches,too-many-locals,too-many-statements
if kind == "Name":
return StatementAssignmentVariableName(
provider=provider,
variable_name=detail,
source=source,
source_ref=source_ref,
)
elif kind == "Attribute":
lookup_source, attribute_name = detail
return StatementAssignmentAttribute(
expression=lookup_source,
attribute_name=mangleName(attribute_name, provider),
source=source,
source_ref=source_ref,
)
elif kind == "Subscript":
subscribed, subscript = detail
return StatementAssignmentSubscript(
expression=subscribed,
subscript=subscript,
source=source,
source_ref=source_ref,
)
elif kind == "Slice":
lookup_source, lower, upper = detail
# For Python3 there is no slicing operation, this is always done
# with subscript using a slice object. For Python2, it is only done
# if no "step" is provided.
use_sliceobj = python_version >= 300
if use_sliceobj:
return StatementAssignmentSubscript(
expression=lookup_source,
source=source,
subscript=makeExpressionBuiltinSlice(start=lower,
stop=upper,
step=None,
source_ref=source_ref),
source_ref=source_ref,
)
else:
return StatementAssignmentSlice(
expression=lookup_source,
lower=lower,
upper=upper,
source=source,
source_ref=source_ref,
)
elif kind == "Tuple":
temp_scope = provider.allocateTempScope("tuple_unpack")
source_iter_var = provider.allocateTempVariable(temp_scope=temp_scope,
name="source_iter")
element_vars = [
provider.allocateTempVariable(temp_scope=temp_scope,
name="element_%d" %
(element_index + 1))
for element_index in range(len(detail))
]
starred_list_var = None
starred_index = None
statements = []
for element_index, element in enumerate(detail):
if element[0] == "Starred":
if starred_index is not None:
raiseSyntaxError(
"two starred expressions in assignment"
if python_version < 390 else
"multiple starred expressions in assignment",
source_ref.atColumnNumber(0),
)
starred_index = element_index
for element_index, element in enumerate(detail):
element_var = element_vars[element_index]
if starred_list_var is not None:
statements.insert(
starred_index + 1,
StatementAssignmentVariable(
variable=element_var,
source=ExpressionListOperationPop(
list_arg=ExpressionTempVariableRef(
variable=starred_list_var,
source_ref=source_ref),
source_ref=source_ref,
),
source_ref=source_ref,
),
)
elif element[0] != "Starred":
statements.append(
StatementAssignmentVariable(
variable=element_var,
source=ExpressionSpecialUnpack(
value=ExpressionTempVariableRef(
variable=source_iter_var,
source_ref=source_ref),
count=element_index + 1,
expected=starred_index or len(detail),
starred=starred_index is not None,
source_ref=source_ref,
),
source_ref=source_ref,
))
else:
assert starred_index == element_index
starred_list_var = element_var
statements.append(
StatementAssignmentVariable(
variable=element_var,
source=ExpressionBuiltinList(
value=ExpressionTempVariableRef(
variable=source_iter_var,
source_ref=source_ref),
source_ref=source_ref,
),
source_ref=source_ref,
))
if starred_list_var is None:
statements.append(
StatementSpecialUnpackCheck(
iterator=ExpressionTempVariableRef(
variable=source_iter_var, source_ref=source_ref),
count=len(detail),
source_ref=source_ref,
))
else:
statements.insert(
starred_index + 1,
makeStatementConditional(
condition=makeComparisonExpression(
comparator="Lt",
left=ExpressionBuiltinLen(
value=ExpressionTempVariableRef(
variable=starred_list_var,
source_ref=source_ref),
source_ref=source_ref,
),
right=makeConstantRefNode(
constant=len(statements) - starred_index - 1,
source_ref=source_ref,
),
source_ref=source_ref,
),
yes_branch=makeRaiseExceptionExpressionFromTemplate(
exception_type="ValueError",
template="""\
not enough values to unpack (expected at least %d, got %%d)""" %
(len(statements) - 1),
template_args=makeBinaryOperationNode(
operator="Add",
left=ExpressionBuiltinLen(
value=ExpressionTempVariableRef(
variable=starred_list_var,
source_ref=source_ref),
source_ref=source_ref,
),
right=makeConstantRefNode(constant=starred_index,
source_ref=source_ref),
source_ref=source_ref,
),
source_ref=source_ref,
).asStatement(),
no_branch=None,
source_ref=source_ref,
),
)
if python_version >= 370:
iter_creation_class = ExpressionBuiltinIterForUnpack
else:
iter_creation_class = ExpressionBuiltinIter1
statements = [
StatementAssignmentVariable(
variable=source_iter_var,
source=iter_creation_class(value=source,
source_ref=source_ref),
source_ref=source_ref,
),
makeTryFinallyStatement(
provider=provider,
tried=statements,
final=(StatementReleaseVariable(variable=source_iter_var,
source_ref=source_ref), ),
source_ref=source_ref,
),
]
# When all is done, copy over to the actual assignment targets, starred
# or not makes no difference here anymore.
for element_index, element in enumerate(detail):
if element[0] == "Starred":
element = element[1]
element_var = element_vars[element_index]
statements.append(
buildAssignmentStatementsFromDecoded(
provider=provider,
kind=element[0],
detail=element[1],
source=ExpressionTempVariableRef(variable=element_var,
source_ref=source_ref),
source_ref=source_ref,
))
# Need to release temporary variables right after successful
# usage.
statements.append(
StatementDelVariable(variable=element_var,
tolerant=True,
source_ref=source_ref))
final_statements = []
for element_var in element_vars:
final_statements.append(
StatementReleaseVariable(variable=element_var,
source_ref=source_ref))
return makeTryFinallyStatement(
provider=provider,
tried=statements,
final=final_statements,
source_ref=source_ref,
)
elif kind == "Starred":
raiseSyntaxError(
"starred assignment target must be in a list or tuple",
source_ref.atColumnNumber(0),
)
else:
assert False, (kind, source_ref, detail)
def buildAssignmentStatementsFromDecoded(provider, kind, detail, source,
source_ref):
# This is using many variable names on purpose, so as to give names to the
# unpacked detail values, and has many branches due to the many cases
# dealt with, pylint: disable=too-many-branches,too-many-locals
if kind == "Name":
variable_ref = detail
return StatementAssignmentVariable(
variable_ref = variable_ref,
source = source,
source_ref = source_ref
)
elif kind == "Attribute":
lookup_source, attribute_name = detail
return StatementAssignmentAttribute(
expression = lookup_source,
attribute_name = attribute_name,
source = source,
source_ref = source_ref
)
elif kind == "Subscript":
subscribed, subscript = detail
return StatementAssignmentSubscript(
expression = subscribed,
subscript = subscript,
source = source,
source_ref = source_ref
)
elif kind == "Slice":
lookup_source, lower, upper = detail
# For Python3 there is no slicing operation, this is always done
# with subscript using a slice object. For Python2, it is only done
# if no "step" is provided.
use_sliceobj = python_version >= 300
if use_sliceobj:
return StatementAssignmentSubscript(
expression = lookup_source,
source = source,
subscript = ExpressionBuiltinSlice(
start = lower,
stop = upper,
step = None,
source_ref = source_ref
),
source_ref = source_ref
)
else:
return StatementAssignmentSlice(
expression = lookup_source,
lower = lower,
upper = upper,
source = source,
source_ref = source_ref
)
elif kind == "Tuple":
temp_scope = provider.allocateTempScope("tuple_unpack")
source_iter_var = provider.allocateTempVariable(
temp_scope = temp_scope,
name = "source_iter"
)
element_vars = [
provider.allocateTempVariable(
temp_scope = temp_scope,
name = "element_%d" % (
element_index + 1
)
)
for element_index in
range(len(detail))
]
starred_list_var = None
starred_index = None
statements = []
for element_index, element in enumerate(detail):
element_var = element_vars[element_index]
if starred_list_var is not None:
if element[0] == "Starred":
raiseSyntaxError(
"two starred expressions in assignment",
source_ref.atColumnNumber(0)
)
statements.insert(
starred_index+1,
StatementAssignmentVariable(
variable_ref = ExpressionTargetTempVariableRef(
variable = element_var,
source_ref = source_ref
),
source = ExpressionListOperationPop(
list_arg = ExpressionTempVariableRef(
variable = starred_list_var,
source_ref = source_ref
),
source_ref = source_ref
),
source_ref = source_ref
)
)
elif element[0] != "Starred":
statements.append(
StatementAssignmentVariable(
variable_ref = ExpressionTargetTempVariableRef(
variable = element_var,
source_ref = source_ref
),
source = ExpressionSpecialUnpack(
value = ExpressionTempVariableRef(
variable = source_iter_var,
source_ref = source_ref
),
count = element_index + 1,
expected = len(detail),
source_ref = source_ref
),
source_ref = source_ref
)
)
else:
starred_index = element_index
starred_list_var = element_var
statements.append(
StatementAssignmentVariable(
variable_ref = ExpressionTargetTempVariableRef(
variable = element_var,
source_ref = source_ref
),
source = ExpressionBuiltinList(
value = ExpressionTempVariableRef(
variable = source_iter_var,
source_ref = source_ref
),
source_ref = source_ref
),
source_ref = source_ref
)
)
if starred_list_var is None:
statements.append(
StatementSpecialUnpackCheck(
iterator = ExpressionTempVariableRef(
variable = source_iter_var,
source_ref = source_ref
),
count = len(detail),
source_ref = source_ref
)
)
statements = [
StatementAssignmentVariable(
variable_ref = ExpressionTargetTempVariableRef(
variable = source_iter_var,
source_ref = source_ref
),
source = ExpressionBuiltinIter1(
value = source,
source_ref = source_ref
),
source_ref = source_ref
),
makeTryFinallyStatement(
provider = provider,
tried = statements,
final = (
StatementReleaseVariable(
variable = source_iter_var,
source_ref = source_ref
),
),
source_ref = source_ref
)
]
# When all is done, copy over to the actual assignment targets, starred
# or not makes no difference here anymore.
for element_index, element in enumerate(detail):
if element[0] == "Starred":
element = element[1]
element_var = element_vars[element_index]
statements.append(
buildAssignmentStatementsFromDecoded(
provider = provider,
kind = element[0],
detail = element[1],
source = ExpressionTempVariableRef(
variable = element_var,
source_ref = source_ref
),
source_ref = source_ref
)
)
# Need to release temporary variables right after successful
# usage.
statements.append(
StatementDelVariable(
variable_ref = ExpressionTargetTempVariableRef(
variable = element_var,
source_ref = source_ref
),
tolerant = True,
source_ref = source_ref,
)
)
final_statements = []
for element_var in element_vars:
final_statements.append(
StatementReleaseVariable(
variable = element_var,
source_ref = source_ref,
)
)
return makeTryFinallyStatement(
provider = provider,
tried = statements,
final = final_statements,
source_ref = source_ref
)
elif kind == "Starred":
raiseSyntaxError(
"starred assignment target must be in a list or tuple",
source_ref.atColumnNumber(0)
)
else:
assert False, (kind, source_ref, detail)