bad-ptr / typecheck.py

Python 3 runtime type checking functions and decorators. Also checks nested iterable objects.

Copyright 2013 Constantin Kulikov

Author: Constantin Kulikov (Bad_ptr) [email protected]
Date: 2013/07/09 21:28:06
License: GPL either version 2 or any later version
Keywords: python 3, typecheck, lib
X-URL: https://github.com/Bad-ptr/typecheck.py

typecheck.py

Intro

The core of this module is rec_type_check function.
You can extend it by defining new subclasses to type_spec class (and then using this subclasses in type signature).
The one thing I'm unshure is how correct the dict handling code couse dict is not ordered collection.
It was tested with Python 3.3.1

Usage notes

Level of error reporting is controlled via __typecheck_error_level variable:
NOTHING = -1
WARNING = 0
EXCEPTION = 1
Which could be set by set_typecheck_error_level function.

Example

from typecheck import (typecheck,accepts,returns, ts_num, set_typecheck_error_level
                       , NOTHING, WARNING, EXCEPTION)

@accepts(ts_num(int, min_num=3,max_num=3),("asd",tuple,list,[int,1]),bool)
def fun(a,b,c,d,test=False):
    print("test =", test)
    return a,b,c,d

fun(1,2,3,("asd",(),[],[2,1]),True)
# test = True
# (1, 2, 3, ('asd', (), [], [2, 1]))

fun(1,2,3,("asd",(),[],[3,1]))
# test = False
# (1, 2, 3, ('asd', (), [], [3, 1]))

returns(1,2,3,(str,(),[ts_num(int)],[1,1]))(fun)

set_typecheck_error_level(EXCEPTION) # EXCEPTION == 1

fun(1,2,3,("asd",(),[],[1,1]),True)
# 'fun' method returns ((1, 2, 3, ('asd', (), [ts_num((<class 'int'>,), min_num=1, max_num=-1)], [1, 1]))),
# but result is (((1, 2, 3, ('asd', (), [], [1, 1])),))
# TypeStack:
#  ts_num not matched: min_num=1, max_num=-1; but actual_num=0 (<class 'int'>,) to ()
# Type not matched: (ts_num((<class 'int'>,), min_num=1, max_num=-1),) to ()
# Type not matched: ([ts_num((<class 'int'>,), min_num=1, max_num=-1)], [1, 1]) to ([], [1, 1])
# Type not matched: (('asd', (), [ts_num((<class 'int'>,), min_num=1, max_num=-1)], [1, 1]),) to (('asd',(), [], [1, 1]),)
#
# Traceback ...

@typecheck()
def foo(a:int,b:bool, *vargs:((1,2),)) -> 'ret_string':
    return 'ret_string'

foo(0,False,(1,2))
# 'ret_string'