snarfing docstrings in c extensions

snarfing docstrings in c extensions

[Samuel Barreto]

Hi everyone,

I'm trying to write a GSL wrapper in guile. I have written a lot of
simple functions using SCM_DEFINE and documented them using the last
SCM_DEFINE macro argument.

Now I'd like to make those docstrings accessible from Scheme code.
The way I do it for now is with this makefile instructions:

%.doc: %.c
	/wherevere/guile/source/code/is/libguile/guile-snarf-docs -o $@ $< \
	-- $(CFLAGS)

%.texi: %.doc
	cat $< | guild snarf-check-and-output-texi > $@

And then call makeinfo on it.
(I had to change some hardcoded path in the guile-snarf-docs scripts so
that it worked from another directory btw.)

So I do am able to generate the info files that I want. My two problems
are:

1. how to use guile-snarf-docs portably ? (I have hardcoded them in my
   Makefile for now.)
2. how to "link" them with functions defined in the extensions ? (I have
   tried to (set! documentation-files "PATH/TO/doc.txt") but I think I
   miss a step so that (procedure-documentation my-gsl-function) returns
   the docstring I want)

And from a broader perspective, is it the way it is supposed to work ? I
mean, am I doing it the right way or are other "guile-extension-writers"
doing it otherwise ?

Thank you for your help,
samuel

Re: snarfing docstrings in c extensions

[Mike Gran]

On Sat, Apr 07, 2018 at 08:59:32PM +0200, Samuel Barreto wrote:

> So I do am able to generate the info files that I want. My two problems
> are:
> 
> 1. how to use guile-snarf-docs portably ? (I have hardcoded them in my
>    Makefile for now.)

Since they don't get installed, it is hard to know the most robust method.
They are used as internal tools to Guile.

> ...

> And from a broader perspective, is it the way it is supposed to work ? I
> mean, am I doing it the right way or are other "guile-extension-writers"
> doing it otherwise ?

That is the way it is supposed to work.  But, I stopped doing it that way.
I had the same sort of problems you are having now.

Instead, I started writing scheme wrappers around my C functions. In C,
let's say I had a library with a function named %foo.  In scheme, I would
make a procedure

(define (foo x)
  "docstring"
  (%foo x))

It is a lot of wasted effort that way, but, it is easier to understand
for me.  I'm not sure I should recommend it, tho.

-Mike Gran

Re: snarfing docstrings in c extensions

[Samuel Barreto]

> On Sat, Apr 07, 2018 at 08:59:32PM +0200, Samuel Barreto wrote:
>
>> So I do am able to generate the info files that I want. My two problems
>> are:
>>
>> 1. how to use guile-snarf-docs portably ? (I have hardcoded them in my
>>    Makefile for now.)
>
> Since they don't get installed, it is hard to know the most robust method.
> They are used as internal tools to Guile.
>
>> ...
>
>> And from a broader perspective, is it the way it is supposed to work ? I
>> mean, am I doing it the right way or are other "guile-extension-writers"
>> doing it otherwise ?
>
> That is the way it is supposed to work.  But, I stopped doing it that way.
> I had the same sort of problems you are having now.
>
> Instead, I started writing scheme wrappers around my C functions. In C,
> let's say I had a library with a function named %foo.  In scheme, I would
> make a procedure
>
> (define (foo x)
>   "docstring"
>   (%foo x))
>
> It is a lot of wasted effort that way, but, it is easier to understand
> for me.  I'm not sure I should recommend it, tho.
>
> -Mike Gran

Thanks for your answer, I was having the feeling that defining scheme
wrappers was the way to go. I agree that it is a lot of wasted effort,
but then a lot of boilerplate code can be written in scheme that way
(taking care of arguments validity, simpler docstrings, stuffs like
that) !

Thanks again !
sam