[Patches] selfnanny.py: checking for "self" in every method

[Moshe Zadka]

This simple nanny checks a Python source for methods that don't have
arguments, or that the first argument isn't called "self". This is an
important enough style guideline that I believe it is worth putting in 
a check, besides, it would stop bugs like

class foo:

	def __init__():
		self.i = 1

a = foo()

NameError: self

---------------- selfnanny.py ----------------------
#!/usr/local/bin/python

import parser, symbol, types

def check_file(file):
	return check_string(file.read())

def check_string(s):
	return check_ast(parser.suite(s))

def check_ast(ast):
	return check_tuple(ast.totuple(1)) # retain line numbers

def check_tuple(tup, classname=None):
	if type(tup) != types.TupleType:
		return []
	problems = []
	if tup[0] == symbol.funcdef:
		if classname is not None:
			args = get_function_args(tup)
			if not args or args[0] != 'self':
				funcname, funcline = tup[2][1:]
				problems.append((funcline, funcname, classname))
		classname = None
	if tup[0] == symbol.classdef:
		classname = tup[2][1]
	for t in tup[1:]:
		problems.extend(check_tuple(t, classname))
	return problems

def get_function_args(tup):
	ret = []
	for t in tup[1:]:
		if t[0] == symbol.parameters:
			parameters = t
	arglist = ()
	for t in parameters[1:]:
		if t[0] == symbol.varargslist:
			arglist = t
	for arg in arglist[1:]:
		if arg[0] == symbol.fpdef:
			ret.append(arg[1][1])
	return ret

def format_problem(problem):
	s = 'line %d: method %s in class %s missing first argument "self"'
	return s % problem

def print_problems(problems):
	for problem in problems:
		print format_problem(problem)

def nanny(filename):
	print_problems(check_file(open(filename)))


if __name__=='__main__':
	import sys
	for filename in sys.argv[1:]:
		nanny(filename)
------------------- selfnanny.py ---------------------

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--
Moshe Zadka <mzadka@geocities.com>. 
http://www.oreilly.com/news/prescod_0300.html