Re: [Axiom-developer] A first attempt at a notangle in Lisp

[Gregory Vanuxem]

Le vendredi 16 février 2007 à 13:44 +0100, Waldek Hebisch a écrit : 
> > I hesitate to say it's useful, but I have what appears to be a (more or
> > less) working notangle command in lisp.  It successfully handles a
> > couple test files, and although I haven't inspected the results it
> > handled most of the contents of boot and interp without crashing. 
> > Unfortunately it's performance is worse than abysmal.  
> 
> Your method of appending content to a chunk was quadratic.  Below
> is a diff changing this to linear method, gives much better speed (at
> least on "nag-e02.boot.pamphlet") but still much slower than Debian
> notangle (0.48s sbcl, 0.028s system version).  AFAICS reading
> pamphlets is still slow (takes 0.4s on "nag-e02.boot.pamphlet").
> 
> 
> --- cl-notangle.lisp.pamphlet 2007-02-16 11:57:23.000000000 +0100
> +++ cl-notangle.lisp.pamphlet 2007-02-16 13:03:47.000000000 +0100
> @@ -365,13 +365,21 @@
>  
>  <<readin-chunk>>=
>  (defun read-in-chunk (curr-chunk-name filename)
> -  (let ((nextline (read-line filename nil)))
> -    (if (or (not (search endchunkchars nextline)) 
> -            (search (concatenate 'string (string #\") endchunkchars)
> -                  nextline)) 
> -     (progn
> -       (add-to-chunk-contents curr-chunk-name nextline)
> -       (read-in-chunk curr-chunk-name filename)))))
> +  (let ((lines nil))
> +     (loop for nextline = (read-line filename nil)
> +            while (or (not (search endchunkchars nextline))
> +                       (search (concatenate 'string (string #\") 
> endchunkchars)
> +                                nextline))
> +            do
> +                  (progn
> +                     (push nextline lines)
> +                     (push (string #\Newline) lines)))
> +      (if lines
> +         (progn
> +            (pop lines)
> +            (add-to-chunk-contents curr-chunk-name
> +                            (apply #'concatenate 'string 
> +                                 (reverse lines)))))))

And another one (it does not remove the last #\Newline):

(defun read-in-chunk (curr-chunk-name filename)
  (let* ((nl (string #\Newline))
        (lines (loop for nextline = (read-line filename nil)
                 while (or (not (search endchunkchars nextline))
                       (search (concatenate 'string (string #\") 
                                        endchunkchars)
                                nextline))
                 collect (concatenate 'string nextline nl))))
      (if lines 
            (add-to-chunk-contents curr-chunk-name 
                            (apply #'concatenate 'string 
                                 lines)))))

Only tested on nag-e02.boot.pamphlet with SBCL.

Greg