Question

I’d like to create a regular expression in Python that will match against a line in Python source code and return a list of function calls.

The typical line would look like this:

something = a.b.method(time.time(), var=1) + q.y(x.m())

and the result should be:

["a.b.method()", "time.time()", "q.y()", "x.m()"]

I have two problems here:

1. creating the correct pattern
2. the catch groups are overlapping

thank you for help

Answer 1

I don’t think regular expressions is the best approach here. Consider the ast module instead, for example:

class ParseCall(ast.NodeVisitor):
    def __init__(self):
        self.ls = []
    def visit_Attribute(self, node):
        ast.NodeVisitor.generic_visit(self, node)
        self.ls.append(node.attr)
    def visit_Name(self, node):
        self.ls.append(node.id)


class FindFuncs(ast.NodeVisitor):
    def visit_Call(self, node):
        p = ParseCall()
        p.visit(node.func)
        print ".".join(p.ls)
        ast.NodeVisitor.generic_visit(self, node)


code = 'something = a.b.method(foo() + xtime.time(), var=1) + q.y(x.m())'
tree = ast.parse(code)
FindFuncs().visit(tree)

result

a.b.method
foo
xtime.time
q.y
x.m