On 2026-04-03 13:23, Maciek Godek wrote:

> FWIW "is" is also used by SRFI-156 for an entirely different purpose

Hi Maciek!

should be not a big deal, as we can export with rename/prefix.

(t:test "our test"
 (t:is (is 2 = 2)))

or

(test "our test"
 (is (infix 2 = 2)))

>
> pt., 3 kwi 2026 o 11:57 Jakub T. Jankiewicz <xxxxxx@jcubic.pl> napisał(a):
>
>> The name `is`, in its current form, is problematic. It doesn't make sense
>> semantically. `is` should compare two values not compare if something is
>> truthy.
>>
>> In normal sentence you have:
>>
>> x is y
>>
>> so the prefix notation should be:
>>
>> (is x y)
>>
>> And the best way to implement `is` is using equal.
>>
>> (define (is x y)
>>   (if (not (equal x y))
>>       (signal "Error")))
>>
>> in LISP Scheme, I use JavaScript testing framework called AVA. The tests
>> looks like this:
>>
>> (test "core: values without wrapping"
>>       (lambda (t)
>>         (t.is (values 1) 1)
>>         (t.is #void (values))))
>>
>> t is an object from AVA that have is method. But I use `t.is` macro
>> anyway.
>> LIPS Scheme use JavaScript dot notation.
>>
>> And if `is` must be an assert, like the doc string in example
>> implementation
>> says. Then it should be called accordingly.
>>
>> (assert (= 1 2))
>>
>> I'm not sure what `assert` in the example implementation is (it's used by
>> `is` macro). `assert` is not part of the R7RS.
>>
>> And if guile-ares-rs wants to use `(is x)` this can be easily abstracted
>> with
>> a macro.
>>
>> (define-library (ares-test)
>>   (export (rename assert is))
>>   (import (scheme base)
>>           (test))
>>
>>   (define-syntax assert
>>     (syntax-rules ()
>>       ((_ expr)
>>        (is expr #t)))))
>>
>>
>> Jakub
>>
>> --
>> Jakub T. Jankiewicz, Senior Front-End Developer
>> https://jakub.jankiewicz.org
>> https://lips.js.org
>> https://snapp.md
>> https://koduj.org
>>

--
Best regards,
Andrew Tropin