Current File : //lib/python3/dist-packages/pythran/analyses/locals_analysis.py
"""
Locals computes the value of locals()
"""
from pythran.passmanager import ModuleAnalysis
import pythran.metadata as md
import gast as ast
class Locals(ModuleAnalysis):
"""
Statically compute the value of locals() before each statement
Yields a dictionary binding every node to the set of variable names defined
*before* this node.
Following snippet illustrates its behavior:
>>> import gast as ast
>>> from pythran import passmanager
>>> pm = passmanager.PassManager('test')
>>> code = '''
... def b(n):
... m = n + 1
... def b(n):
... return n + 1
... return b(m)'''
>>> tree = ast.parse(code)
>>> l = pm.gather(Locals, tree)
>>> sorted(l[tree.body[0].body[0]])
['n']
>>> sorted(l[tree.body[0].body[1]])
['b', 'm', 'n']
"""
def __init__(self):
self.result = dict()
self.locals = set()
self.nesting = 0
super(Locals, self).__init__()
def generic_visit(self, node):
super(Locals, self).generic_visit(node)
if node not in self.result:
self.result[node] = self.result[self.expr_parent]
def store_and_visit(self, node):
self.expr_parent = node
self.result[node] = self.locals.copy()
self.generic_visit(node)
def visit_Module(self, node):
self.expr_parent = node
self.result[node] = self.locals
self.generic_visit(node)
def visit_FunctionDef(self, node):
# special case for nested functions
if self.nesting:
self.locals.add(node.name)
self.nesting += 1
self.expr_parent = node
self.result[node] = self.locals.copy()
parent_locals = self.locals.copy()
for default in node.args.defaults:
self.visit(default)
for arg in node.args.args:
if arg.annotation:
self.visit(arg.annotation)
if node.returns:
self.visit(node.returns)
self.locals.update(arg.id for arg in node.args.args)
for stmt in node.body:
self.visit(stmt)
self.locals = parent_locals
self.nesting -= 1
def visit_Assign(self, node):
self.expr_parent = node
self.result[node] = self.locals.copy()
md.visit(self, node)
self.visit(node.value)
self.locals.update(t.id for t in node.targets
if isinstance(t, ast.Name))
for target in node.targets:
self.visit(target)
def visit_For(self, node):
self.expr_parent = node
self.result[node] = self.locals.copy()
md.visit(self, node)
self.visit(node.iter)
self.locals.add(node.target.id)
for stmt in node.body:
self.visit(stmt)
for stmt in node.orelse:
self.visit(stmt)
def visit_Import(self, node):
self.result[node] = self.locals.copy()
self.locals.update(alias.name for alias in node.names)
def visit_ImportFrom(self, node):
self.result[node] = self.locals.copy()
self.locals.update(alias.name for alias in node.names)
def visit_ExceptHandler(self, node):
self.expr_parent = node
self.result[node] = self.locals.copy()
if node.name:
self.locals.add(node.name.id)
node.type and self.visit(node.type)
for stmt in node.body:
self.visit(stmt)
# statements that do not define a new variable
visit_Return = store_and_visit
visit_Yield = store_and_visit
visit_Try = store_and_visit
visit_AugAssign = store_and_visit
visit_Print = store_and_visit
visit_While = store_and_visit
visit_If = store_and_visit
visit_Raise = store_and_visit
visit_Assert = store_and_visit
visit_Expr = store_and_visit
visit_Pass = store_and_visit
visit_Break = store_and_visit
visit_Continue = store_and_visit
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