Re: Code for cond*

[JD Smith]

> On Jan 25, 2024, at 10:17 AM, JD Smith <jdtsmith@gmail.com> wrote:
> 
> 
> 
>> On Jan 25, 2024, at 8:57 AM, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>> 
>>>> 
>>>> (cond-let
>>>> (((var value)
>>>>  (dvar (derived-from var))
>>>>  ((has-the-right-stuff-p dvar)))
>>>> (cons 'correct dvar))
>>>> 
>>>> (((foo value2)
>>>>  (bar (1- foo))
>>>>  ((< bar 0)))
>>>> (cons 'incorrect bar))
>>>> 
>>>> (t nil))
>> 
> 
>> Personally, I was thinking of a syntax like
>> 
>>   (my-cond
>>    (:let var value)
>>    (:let dvar (derived-from var))
>>    ((has-the-right-stuff-p dvar)
>>     (cons 'correct dvar))
>> 
>>    (:let foo value2)
>>    (:let bar (1- foo))
>>    ((< bar 0)
>>     (cons 'incorrect bar))
>> 
>>    (t nil))

And it perhaps goes without saying that the two approaches could be combined :) 
—

(cond-let
  (:let var-for-rest value)
  (simple0-using-var-for-rest body0) ; a normal cond-like clause
  (bindings1 body1-including-var-for-rest)
  
  (:let another-var (some-function var-for-rest))
  (bindings2-using-another-var body2)
  (bindings3 body3-using-another-var)
  (t fallthrough-body))