# add implicit multiplication operators, e.g. '5x' -> '5*x'
string = LinExpr._RE_NUM_VAR.sub(r'\1*\2', string)
tree = ast.parse(string, 'eval')
- return cls._fromast(tree)
+ expr = cls._fromast(tree)
+ if not isinstance(expr, cls):
+ raise SyntaxError('invalid syntax')
+ return expr
def __repr__(self):
string = ''
"""
return Dummy(self.name)
- @classmethod
- def _fromast(cls, node):
- if isinstance(node, ast.Module) and len(node.body) == 1:
- return cls._fromast(node.body[0])
- elif isinstance(node, ast.Expr):
- return cls._fromast(node.value)
- elif isinstance(node, ast.Name):
- return Symbol(node.id)
- raise SyntaxError('invalid syntax')
-
def __repr__(self):
return self.name