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""" Classes used to represent assignment statements. """
# Standard library imports.
import compiler
from compiler.visitor import ASTVisitor
# Enthought library imports.
from enthought.traits.api import Any, Bool, HasTraits, Instance, Int, List, Str
class Assign(HasTraits):
""" An assignment statement. """
#### 'Assign' interface ###################################################
# The namespace that the assignment statement is in.
namespace = Instance(
'enthought.envisage.developer.code_browser.namespace.Namespace'
)
# The line number within the module at which the assignment statement
# appears.
lineno = Int
# The names being assigned to (in Python there can be more than one).
targets = List(Str)
# The expression being assigned to the targets (an AST node).
expr = Any
# We only care about assignments to trait types, not literals or
# expressions etc.
source = Str
# Is this a trait assignment?
is_trait = Bool(False)
###########################################################################
# 'object' interface.
###########################################################################
def __str__(self):
""" Returns an informal string representation of the object. """
return 'Assign %s at %d' % (', '.join(self.targets), self.lineno)
class AssignFactory(HasTraits):
""" A factory for assignment statements. """
###########################################################################
# 'AssignFactory' interface.
###########################################################################
def from_ast(self, namespace, node):
""" Creates an assignment statement from an AST node. """
# Create a new assignment statement.
assign = Assign(
namespace = namespace,
lineno = node.lineno,
expr = node.expr
)
# Walk the AST picking out the things we care about!
compiler.walk(node, AssignVisitor(assign))
return assign
class AssignVisitor(ASTVisitor):
""" An AST visitor for assigment statements. """
###########################################################################
# 'object' interface.
###########################################################################
def __init__(self, assign):
""" Creates a new visitor. """
self.assign = assign
return
###########################################################################
# 'ASTVisitor' interface.
###########################################################################
def visitAssName(self, node):
""" Visits an assignment node. """
self.assign.targets.append(node.name)
return
def visitCallFunc(self, node):
""" Visits a function call node. """
function_name = self._get_name(node.node)
self.assign.source = function_name
return
def visitName(self, node):
""" Visits a name node. """
self.assign.source = node.name
return
def visitGetattr(self, node):
""" Visits a getattr node. """
self.assign.source = self._get_name(node)
return
###########################################################################
# Private interface.
###########################################################################
def _get_name(self, node):
""" Returns the (possibly dotted) name from a node. """
# fixme: Work out when node can be none here!!!!! I think it is safe
# to ignore it in terms of working out what is a trait, but it would
# be nice to know what is going on ;^)
if node is not None:
if isinstance(node, basestring):
name = node
elif not hasattr(node, 'getType'):
name = ''
elif node.getType() == compiler.ast.Name:
name = node.name
else:
names = [self._get_name(child) for child in node.getChildren()]
name = '.'.join(names)
else:
name = ''
return name
#### EOF ######################################################################
|
