Re: (format ... "~A" (apply #'format nil errorstring arguments))

[Sam S. <sd...@gn...>]

> * Bruno Haible <oe...@py...t> [2017-08-23 22:09:17 +0200]:
>
> Sam wrote on 2017-08-02:
>> In clos-method2.lisp and many other places you have this pattern:
>> 
>> --8<---------------cut here---------------start------------->8---
>> (defmacro program-error-reporter (caller)
>>   `#'(lambda (form detail errorstring &rest arguments)
>>        (apply #'sys::lambda-list-error form detail
>>               "~S: ~A" ,caller (apply #'format nil errorstring arguments))))
>> --8<---------------cut here---------------end--------------->8---
>> 
>> Why not
>> 
>> --8<---------------cut here---------------start------------->8---
>> (defmacro program-error-reporter (caller)
>>   `#'(lambda (form detail errorstring &rest arguments)
>>        (apply #'sys::lambda-list-error form detail
>>               "~S: ~?" ,caller errorstring arguments)))
>> --8<---------------cut here---------------end--------------->8---
>> 
>> The only place where the second pattern is used is invalid-method-error
>> and method-combination-error in close-methcomb2.
>
> I replied:
>> Both are equivalent.
>
> Not always. When the format string contains directives that are
> sensitive on the current column position (tabulate, justification, all
> pretty-printing directives) or newline state (fresh-line,
> elastic-newline), the two idioms may produce different results.

Valid point, and, I think, an excellent argument in favor of the second
version.

Thanks

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