Re: Adding String to Beginning of Lines

[Stefan Monnier <monnier@iro.umontreal.ca>]

> If you look at the definition:
>
> (defsubst string-empty-p (string)
>   "Check whether STRING is empty."
>   (string= string ""))

FWIW, I agree with Louis on this one: (equal string "") is shorter and
just as clear as (or even more clear than) `(string-empty-p string)`,
so I'm no fan of such a definition.

> | (defun rcd-string-empty-p (s)
> |   "Returns T if string is empty or NIL"
> |   (let ((s (if (null s) "" s)))
> |     (if (stringp s)
> | 	(if (zerop (length s)) t nil))))
>
> That's more or less the same as
>
> (defun rcd-string-empty-p (s)
>   (or (null s) (and (stringp s) (zerop (length s)))))

BTW since (length nil) is zero, this can be reduced in most cases to
(zerop (length s)), the main difference being that the shorter
definition signals an error if passed an object that's neither an array
nor a proper list.

> But why handling an empty list specially, and not other empty sequences,
> like the empty vector?  That's what `seq-empty-p' in seq.el does, btw.

Indeed,


        Stefan