today’s hacked-together but task-appropriate refactoring aid

find-webpage.py

#!/usr/bin/env python2
# -*- coding: utf-8 -*-

import ast
import codeop


def try_get_context(source_lines, lineno, limit=10):
    # does not try very hard
    line = source_lines[node.lineno - 1]

    extend = 0
    source = 'def _():\n    ' + line.lstrip()

    while extend < limit:
        try:
            code = codeop.compile_command(source + '\n\n') is not None
        except (SyntaxError, OverflowError, ValueError):
            return 0, False

        source += '\n' + source_lines[node.lineno + extend]
        extend += 1

        if code:
            return extend, False

    return limit, True


if __name__ == '__main__':
    import io
    import sys

    for path in sys.argv[1:]:
        with io.open(path, "rb") as f:
            source = f.read()

        module = ast.parse(source, filename=path)

        for node in ast.walk(module):
            if isinstance(node, ast.Call):
                if isinstance(node.func, ast.Name):
                    match = node.func.id == 'webpage'
                elif isinstance(node.func, ast.Attribute):
                    match = node.func.attr == 'webpage'
                else:
                    raise Exception("Unexpected")

                if match:
                    if (
                        len(node.args) >= 4 or
                        'options' in (kw.arg for kw in node.keywords) or
                        node.starargs is not None or
                        node.kwargs is not None
                    ):
                        source_lines = source.decode('utf-8').splitlines()
                        line = source_lines[node.lineno - 1]

                        location = '%s:%i:%i' % (path, node.lineno, node.col_offset)
                        align = ' ' * (len(location) - 2)
                        print '%s %s' % (location, line)

                        extend, continues = try_get_context(source_lines, node.lineno)

                        for i in range(extend):
                            print '%s | %s' % (align, source_lines[node.lineno + i])

                        if continues:
                            print align + '   ...'

                        print