Re: [Chicken-users] Re: A few questions

[Kon Lovett]

On Jan 29, 2008, at 11:08 AM, Hans Nowak wrote:

> First of all, thanks to everybody who replied.
>
> Re docstrings: My next question would be, is it possible to add  
> them (e.g. as a library)?  And would it be desirable to do so?   
> Apparently it is already possible to write code like:
>
> (define (foo x)
>   "docstring for foo"
>   ...body...)
>
> It just has no effect, currently (or so I assume).  Would it be  
> possible to write a function/macro/etc like this:
>
> > (get-docstring foo)
> "docstring for foo"

Yes, but not with a documented interface. The procedure  
'(##sys#decorate-lambda proc pred decorator)' can create arbitrary  
"decorations" for a procedure. Then, '(##sys#lambda-decoration proc  
pred)' can retrieve it.

Let me look into this.

> ...?
>
> The reason I am asking is that someone suggested I should write  
> doctest for Scheme.  For those not familiar with it, this is a  
> Python module that allows you to add tests to docstrings.  It does  
> so by emulating the interactive interpreter; e.g. you could write:
>
> (define (plus a b)
>   "Add two numbers.
>
>    >>> (plus 2 2)
>    4
>    >>> (plus 1 2 3)
>    Error: bad argument count
>   "
>   ...implementation...)
>
> More here:
>
> http://docs.python.org/lib/module-doctest.html
>
> Does Chicken have something similar?  It doesn't have docstrings,  
> but it would still be possible to write unit tests like you're  
> typing them in the REPL.  I did not find an egg that does this kind  
> of testing, though.  Does such a library exist?  Would it be useful  
> to have?

No. But see above. (I wouldn't put the tests in a docstring but in a  
test decoration.)

There are plenty of testing eggs. Both testeez & testbase provide a  
REPL style test interface. But I don't use the REPL style for unit  
tests.

> Re using files as modules and scripts: I just found csi's -ss  
> option, which pretty much does what I want, although in a different  
> way.
>
> Anyway, I have another question: when you define a function, how  
> much "introspection" is possible?  E.g. from another thread  
> ("Runtime arity") I learned that it's possible to get the  
> function's signature.  Is there also a way to get e.g. the  
> function's body?  (My guess is, probably not, but I thought I'd ask.)

No. Why do you want it?

> Thanks,
>
> --Hans
>
>
>
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Best Wishes,
Kon