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

[Bruno H. <br...@cl...>]

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.

I don't know whether this has an impact on your change from 2017-08-02.

Bruno