def _transform_children(self, node):
if not isinstance(node, Node):
raise ValueError('Expected a Node, got %r' % node)
# In these trees, strings and Nodes are leaves
leaves = (str, Node)
tree_map = partial(tree.tree_map, leaves=leaves)
children = tree_map(partial(self.transform), node.getChildrenTree())
return node.__class__(*children)
def _transform_children(self, node):
if not isinstance(node, Node):
raise ValueError('Expected a Node, got %r' % node)
# In these trees, strings and Nodes are leaves
leaves = (str, Node)
tree_map = partial(tree.tree_map, leaves=leaves)
children = tree_map(partial(self.transform), node.getChildrenTree())
return node.__class__(*children)
def test_transformer_base_class(self):
'Transformer base class'
test = partial(self._base, Transformer())
# Transformer.transform doesn't change anything
test('a = 0', 'a = 0')
test('a = b', 'a = b')
test('if t == u-1: a = b,f(c)', 'if t == u-1: a = b,f(c)')
# ...
# Transformer.transform makes deep copies by default
code = 'if t == u: a,b = [1]+[2]\nreturn sum(b,a)'
a = parse(code)
b = Transformer().transform(a)
b.node.nodes[1] = parse('yield x').node.nodes[0]
b.node.nodes[0].tests[0][0].ops[0] = parse('t > 0').node.nodes[0].expr
b.node.nodes[0].tests[0][1].nodes[0].expr.left.nodes[0] = 5
self.assertNotSimilar(b, parse(code))
self.assertSimilar(a, parse(code))
def test_transformer_base_class(self):
'Transformer base class'
test = partial(self._base, Transformer())
# Transformer.transform doesn't change anything
test('a = 0', 'a = 0')
test('a = b', 'a = b')
test('if t == u-1: a = b,f(c)', 'if t == u-1: a = b,f(c)')
# ...
# Transformer.transform makes deep copies by default
code = 'if t == u: a,b = [1]+[2]\nreturn sum(b,a)'
a = parse(code)
b = Transformer().transform(a)
b.node.nodes[1] = parse('yield x').node.nodes[0]
b.node.nodes[0].tests[0][0].ops[0] = parse('t > 0').node.nodes[0].expr
b.node.nodes[0].tests[0][1].nodes[0].expr.left.nodes[0] = 5
self.assertNotSimilar(b, parse(code))
self.assertSimilar(a, parse(code))
def transformAssign(self, node):
# Only transform constant assignments
if not is_const(node.expr):
return self._transform_children(node)
# '__foo' names come from each lhs name at the head of the assignment:
# 'l = a,b = 0,1' -> 'l = a,b = __a,__b', { '__a':0, '__b':1 }
#
# Unpack the rhs enough to map each '__foo' name to a value.
# 'a,l = 0,[1,2]' -> 'a,l = __a,__l', { '__a':0, '__l':[1,2] }
# 'a,l = 2' -> SyntaxError
def lvalue_name(node):
'Construct a "magic" name to represent an l-value.'
prefix = sep = '__'
dot = '_'
if isinstance(node, AssName):
return prefix + node.name
elif isinstance(node, AssAttr):
name = node.attrname
expr = node.expr
while isinstance(expr, Getattr):
name = sep.join([expr.attrname, name])
expr = expr.expr
if isinstance(expr, Name):
expr_name = expr.name
else:
expr_name = dot
return prefix + sep.join([expr_name, name])
# In these trees, strings and tuples are leaves
leaves = (str, tuple, AssAttr, AssName)
tree_zip = partial(tree.tree_zip, leaves=leaves)
flatten = partial(tree.flatten, leaves=leaves)
tree_embeds = partial(tree.tree_embeds, leaves=leaves)
# Grab the (right-most) lhs and the rhs
lhs, rhs = node.nodes[-1], node.expr
# Associate constants with l-value names
if not tree_embeds(lhs, rhs):
raise SyntaxError('Not enough r-values to unpack: %s' % node)
zipped = flatten(tree_zip(lhs, rhs))
const_ast_for = map_keys(lambda v: lvalue_name(v), dict(zipped))
# Gather name<->const mappings for names we haven't seen before
name_for = {}
for name in const_ast_for.keys():
if name not in self.const_for.keys():
self.const_for[name] = eval_ast(Expression(const_ast_for[name]))
assert const_ast_for[name] not in name_for
name_for[const_ast_for[name]] = name
class C(Transformer):
def transform(self, node):
if isinstance(node, Node) and node in name_for.keys():
return Name(name_for[node])
else:
return super(C, self).transform(node)
return Assign(node.nodes, C().transform(rhs))
def transformAssign(self, node):
# Only transform constant assignments
if not is_const(node.expr):
return self._transform_children(node)
# '__foo' names come from each lhs name at the head of the assignment:
# 'l = a,b = 0,1' -> 'l = a,b = __a,__b', { '__a':0, '__b':1 }
#
# Unpack the rhs enough to map each '__foo' name to a value.
# 'a,l = 0,[1,2]' -> 'a,l = __a,__l', { '__a':0, '__l':[1,2] }
# 'a,l = 2' -> SyntaxError
def lvalue_name(node):
'Construct a "magic" name to represent an l-value.'
prefix = sep = '__'
dot = '_'
if isinstance(node, AssName):
return prefix + node.name
elif isinstance(node, AssAttr):
name = node.attrname
expr = node.expr
while isinstance(expr, Getattr):
name = sep.join([expr.attrname, name])
expr = expr.expr
if isinstance(expr, Name):
expr_name = expr.name
else:
expr_name = dot
return prefix + sep.join([expr_name, name])
# In these trees, strings and tuples are leaves
leaves = (str, tuple, AssAttr, AssName)
tree_zip = partial(tree.tree_zip, leaves=leaves)
flatten = partial(tree.flatten, leaves=leaves)
tree_embeds = partial(tree.tree_embeds, leaves=leaves)
# Grab the (right-most) lhs and the rhs
lhs, rhs = node.nodes[-1], node.expr
# Associate constants with l-value names
if not tree_embeds(lhs, rhs):
raise SyntaxError('Not enough r-values to unpack: %s' % node)
zipped = flatten(tree_zip(lhs, rhs))
const_ast_for = map_keys(lambda v: lvalue_name(v), dict(zipped))
# Gather name<->const mappings for names we haven't seen before
name_for = {}
for name in const_ast_for.keys():
if name not in self.const_for.keys():
self.const_for[name] = eval_ast(Expression(
const_ast_for[name]))
assert const_ast_for[name] not in name_for
name_for[const_ast_for[name]] = name
class C(Transformer):
def transform(self, node):
if isinstance(node, Node) and node in name_for.keys():
return Name(name_for[node])
else:
return super(C, self).transform(node)
return Assign(node.nodes, C().transform(rhs))
