Re: Why (substring "abc" 0 4) does not return "abc" instead of an error?

[Bastien <bzg@gnu.org>]

Hi Pascal,

"Pascal J. Bourguignon" <pjb@informatimago.com> writes:

> (defun mysubstring (str start end)
>   (substring str (max start 0)
>                  (if end
>                      (min end (length str))
>                      (length str))))
>
> and use (mysubstring "abc" 0 4) --> "abc" 
> instead of substring.

I know how to implement my own defun for this but thanks.

My question was about what _justifies_ the current behavior.

Dmitry said at least JS, Ruby, Python and perhaps C++ uses 
the behavior I mention --  so I'm even more curious now.

I am not saying the behavior I expect is superior, it is
just the one I expect -- I would like to read a good reason
for the current one.  Juanma have a point when he said that 
the current behavior is consistent with other *-substring 
functions but again, `substring' seems different to me.

> The point of lisp is to let you define your own language seamlessly.

True.  

But the point of sharing code is also to not reinvent the 
wheel, right?

Best,

-- 
 Bastien