[Python-ideas] where statement in Pyret

[Markus Unterwaditzer]

While it is a nice idea, i don't think this feature deserves its own syntax. Besides doctests, another way of achieving this in Python might be:

    def sum(l):
        # implementation of sum
    
    def test_sum():
        assert sum([]) == 0
        assert sum([1, 2, 3]) == 6

which IMO is nice enough.

-- Markus

"Tarek Ziadé" <tarek at ziade.org> wrote:
>Hey
>
>I've read about Pyret on hackernews: http://www.pyret.org/
>
>and found the 'where' statement very compeling. Functions can end with
>a
>where that contains small unit
>tests.
>
>>From the documentation example:
>
>fun sum(l):
>  cases(List) l:
>    | empty => 0
>    | link(first, rest) => first + sum(rest)
>  end
>where:
>  sum([]) is 0
>  sum([1, 2, 3]) is 6
>end
>
> 
>It's quite similar to the doctests ideas I guess - but not intended to
>be documentation like them.
>
>I ended up disliking docttests because of this doc+test duality by the
>way: it often ends up as a
>not so good documentation and not so good tests.
>
>Anyways, having a dedicated keyword to append after a function some
>tests as part of the language
>has benefits imho:
>
>- the scope is reduced to the function - so it helps making 'real'
>isolated unit tests.
>- we do have the unittest conventions, but here it make tests a first
>class citizen in the language.
>
>Cheers
>Tarek
>
>
>
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>
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