Parsing naive install_requires with AST

parse.py

import ast

tree = ast.parse(open('setup.py').read())

names = {}

def strings(tree):
    ret = []
    for node in ast.walk(tree):
        if isinstance(node, ast.Name):
            ret.extend(names.get(node.id) or [])
        if isinstance(node, ast.Str):
            ret.append(node.s)
    return ret


for node in ast.walk(tree):
    if isinstance(node, ast.Assign):
        value = strings(node.value)
        for target in node.targets:
            if isinstance(target, ast.Name):
                names[target.id] = value


for node in ast.walk(tree):
    if isinstance(node, ast.Call) and isinstance(node.func, ast.Name):
        if not node.func.id == 'setup':
            continue
        for keyword in node.keywords:
            if keyword.arg == 'install_requires':
                print strings(keyword.value)