Re: first-is (3 versions, Elisp hangup) (was: Re: we need *modularity* [last problem])

[Emanuel Berg <incal@dataswamp.org>]

Oh, no!

;; (elpat--first-is   "" "same") ; t
;; (elpat--first-is-2 "" "same") ; nil
;; (elpat--first-is-3 "" "same") ; nil

;; (elpat--first-is   "s" "") ; nil
;; (elpat--first-is-2 "s" "") ; crash
;; (elpat--first-is-3 "s" "") ; crash

;; (elpat--first-is   "" "") ; t
;; (elpat--first-is-2 "" "") ; crash
;; (elpat--first-is-3 "" "") ; crash

But hang on, I have some thing for that as well. Here:

(defun string-data-p (str)
  (and (stringp str) (not (string= str "")) str))

Heh, see where this is going?

It is clear to me that Elisp isn't a language designed or
optimized for devel speed and productivity.

Lisp could be (I _think_, much more so anyway) - but I guess
it won't happen.

> (defun elpat--first-is-3 (s str)
>   (and (stringp s)
>        (stringp str)
>        (string= s (char-to-string (seq-first str)))))
>
> (defun elpat--first-is-2 (s str)
>   (and (stringp s)
>        (stringp str)
>        (string= s (substring str 0 1))))
>
> (defun elpat--first-is (s str)
>   (and (cl-every #'stringp (list s str))
>        #1=(string-match s str)
>        (zerop #1#)))
>
> ;; (elpat--first-is   "s" "same")
> ;; (elpat--first-is-2 "s" "same")
> ;; (elpat--first-is-3 "s" "same")
>
> ;; (elpat--first-is   "s" "lame")
> ;; (elpat--first-is-2 "s" "lame")
> ;; (elpat--first-is-3 "s" "lame")

-- 
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https://dataswamp.org/~incal