Re: Guarded Function Definitions Package

Hi Birdt,

Welcome to the Chicken community!

I have briefly looked over the code, and I it looks well-written to me.
You're using implicit-renaming and gensyms which should avoid the most
common pitfalls. In my opinion, your use of unquoted splicing makes it all
very readable.

You could use handle-exceptions [0] to test it if you use error or raise
instead of assert. These are part of chicken itself and as such requires no
external dependencies.

As puplishing this as an egg, however, and in danger of being discouraging,
I wonder how general this macro is. For example, variables are always
placed as the first argument:

... (x (even?) (> 5)) ...
=> (and (even? x) (> x 5)) ...

Things like this may be considered un-Schemeish by some. There are many
existing helpers that let you address arument-placement like this. For
example: flip, compose, cut/cute, case-lambda, -> and ->> and many more. In
the regime above, it may be hard to take advantage of these. Writing a
useful, reusable and expressive macro is truly an art.

I don't know if it's relevant for your use-case, but Chicken allow you to
declare types [1]. These are sometimes are able to detect errors at compile
time.

When I first started writing Scheme, I wrote a macro for everything. One
for looping, one for starting threads, and one for including the git tag at
compile-time and so on. But I learned that custom macros make code harder
to read in the long run because you can't jump into a section and
understand it. You first need to review it's macros. That cost is bigger
than the benefit of a slightly shorter program.

This is just my opinion, and I hope this isn't discouraging. Keep writing
macros and post them here! We appreciate your input.

K.
[0]: http://api.call-cc.org/5/doc/chicken/condition/handle-exceptions
[1]: http://wiki.call-cc.org/man/5/Types

On Tue, Aug 6, 2024, 14:43 birdt_--- via <[email protected]> wrote:

> Hi all!
>
> I'm not very experienced with Scheme or Chicken, but I've written a small
> macro which I've found useless on a few learning projects which I thought
> I'd share with the hope of getting it included on the package list.
>
> The repo is here <https://github.com/BirDt/guards/> (along with a
> release-info, provided I understand the format correctly), I'd appreciate
> any feedback on the macro itself as I'm sure it's written in a very
> inefficient way (I'm not even sure if using `assert` is best here, instead
> of a conditional `error`) and I'd like to improve it since I like using
> this syntax.
>
> Also, is there a way to capture assertion failures at runtime? I've
> neglected to write any unit tests at present since I'd like to do this
> without any third party libraries simply for the learning experience.
>
> Thanks and o7,
> Jakub
>