List names of functions declared in a Python module in the order of declaration

list_functions_in_module_ordered.py

"""
Gets list of functions in a module, preserve declaration order.

This cannot be done with inspect.getmembers() or dir() because they lose the order.
Have to construct AST with ast.
"""

import ast
import importlib
import os.path


class Parser(ast.NodeVisitor):
    def __init__(self):
        super(Parser, self).__init__()
        self.functions = []

    def visit_FunctionDef(self, node):
        self.functions.append(node.name)


class Inspector(object):
    def __init__(self, mod_name):
        self.mod_name = mod_name
        self._mod_filename = None
        self._ast = None
        self._parser = None

    @property
    def mod_filename(self):
        if self._mod_filename is None:
            direct_path = self.mod_name.replace('.', '/') + '.py'
            if os.path.exists(direct_path):
                self._mod_filename = direct_path
            else:
                m = importlib.import_module(self.mod_name)
                self._mod_filename = m.__file__
        return self._mod_filename

    @property
    def ast(self):
        if self._ast is None:
            with open(self.mod_filename) as f:
                self._ast = ast.parse(f.read(), filename=self.mod_filename)
        return self._ast

    @property
    def parser(self):
        if self._parser is None:
            self._parser = Parser()
            self._parser.visit(self.ast)
        return self._parser

    def get_function_names(self):
        return self.parser.functions


print(Inspector('idemseq.examples.context_provider').get_function_names())