def _hoist_variables_to_piglet_context(astnode, exclude_functions=frozenset()):
"""
Template functions extract all local variables from the
:var:`piglet.runtime.data` thread local
"""
# Names we never hoist.
# "None" would raise a SyntaxError if we try assigning to it. The others
# are used internally by piglet and need to be reserved.
restricted_names = {'None', 'True', 'False',
'value_of', 'defined', 'Markup', 'iter',
'AttributeError', 'Exception',
'print', 'getattr'}
# Mapping of function -> names used within function
func_names = {}
# Mapping of {function name: {<ancestor nodes>, ...}}
func_ancestors = {}
# All names discovered together with their ast location
names = []
for fn, ancestors in _get_function_defs(astnode):
func_ancestors.setdefault(fn.name, set()).add(ancestors)
func_names[fn] = set()
is_reserved = lambda n: n.id in restricted_names
is_piglet = lambda n: n.id.startswith('__piglet')
is_function = lambda n, a: any(
a[:len(fancestors)] == fancestors
for fancestors in func_ancestors.get(n.id, set()))
names = ((ancestors, node)
for node, ancestors in _get_out_of_scope_names(astnode)
if not (is_reserved(node) or
is_piglet(node) or
is_function(node, ancestors)))
for ancestors, node in names:
container_func = next((a
for a in reversed(ancestors)
if isinstance(a, FunctionDef)), None)
if container_func in exclude_functions:
continue
if container_func is None:
lineno = getattr(node, 'lineno', '(unknown line number)')
raise AssertionError("Unexpected variable found at {}: {}"
.format(lineno, node.id))
func_names[container_func].add(node.id)
for f, names in func_names.items():
assignments = [
Assign(targets=[StoreName('__piglet_ctx')],
value=Subscript(
value=LoadAttribute('__piglet_rtdata.context'),
slice=Index(value=Num(n=-1)),
ctx=Load()
))
]
for n in sorted(names):
is_builtin = n in builtin_names
if is_builtin:
default = LoadAttribute(
LoadAttribute('__piglet_rt', 'builtins'), n)
else:
default = Call(func=Attribute(value=Name(id='__piglet_rt',
ctx=Load()),
attr='Undefined',
ctx=Load()),
args=[Str(s=n)],
starargs=None,
kwargs=None,
keywords=[])
value = Call(func=Attribute(value=Name(id='__piglet_ctx',
ctx=Load()),
attr='get',
ctx=Load()),
args=[Str(s=n), default],
starargs=None,
kwargs=None,
keywords=[])
a = Assign(targets=[Name(id=n, ctx=Store())], value=value)
assignments.append(a)
f.body[0:0] = assignments
return astnode
