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4 points by nex3 6147 days ago | link | parent

I don't really see Anarki as a fork of Arc, and certainly not as a competing implementation. I see it as a place to put bug-fixing patches, to experiment with crazy implementation ideas, to keep libraries and add-ons, and so forth. I keep it up-to-date with the latest arcn.tar, and we all try not to make the API incompatible. If PG ever says that there's some feature in it that he won't include in the official distribution, at least one that involves patching ac.scm, we'll get rid of it. The rest can be included as arcn-compatible libraries.

So I don't predict that there'll really be incompatibility issues in the future.



2 points by sacado 6147 days ago | link

Well, as far as I know, there are some improvements (bug fixes & efficiency issues) made in ac.scm from arc2 that have been ignored on the anarki version (where other patches & fixes were previously applied). In other words, anarki's current version of ac.scm is much closer to anarki's "arc1+" version than to arc2's version. I tried to merged them a few days ago, but apparently it broke in some versions of mzscheme. I might try again later.

No big deal however, these are only minor issues, but it might get harder as pg improves his own version while we get addicted to (and improve) the cool features implemented in the version we're working on. One day or another, it will be almost impossible to merge them. (Animal species work that way btw)

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3 points by nex3 6147 days ago | link

There shouldn't be anything in arc2 that isn't in Anarki except maybe a couple srv.arc improvements that are more or less a subset of the improvements made earlier in Anarki.

I did a full merge of arc2 when it was released (see http://www.arclanguage.org/item?id=3427), and when there were conflicts, generally favored PG's solutions to the ones already present. If there is anything missing, I'd love to know what it is.

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2 points by sacado 6147 days ago | link

For example, arc-call was change a little, for performance reasons I guess :

  (define (ac-call fn args env)
   (let ((macfn (ac-macro? fn)))
    (cond (macfn
           (ac-mac-call macfn args env))
          ((and (pair? fn) (eqv? (car fn) 'fn))
           `(,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          ((= (length args) 0)
           `(ar-funcall0 ,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          ((= (length args) 1)
           `(ar-funcall1 ,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          ((= (length args) 2)
           `(ar-funcall2 ,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          ((= (length args) 3)
           `(ar-funcall3 ,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          ((= (length args) 4)
           `(ar-funcall4 ,(ac fn env) ,@(map (lambda (x) (ac x env)) args)))
          (#t
           `(ar-apply ,(ac fn env)
                      (list ,@(map (lambda (x) (ac x env)) args)))))))
Instead of the code currently in anarki, taken from arc1 :

  (define (ac-call fn args env)
  (let ((macfn (ac-macro? fn)))
    (if macfn
      (ac-mac-call macfn args env)
      (let ((afn (ac fn env))
            (aargs (map (lambda (x) (ac x env)) args))
            (nargs (length args)))
        (cond
          ((eqv? (xcar fn) 'fn)
           `(,afn ,@aargs))
          ((and (>= nargs 0) (<= nargs 4))
           `(,(string->symbol (string-append "ar-funcall" (number->string nargs)))
              ,afn ,@aargs))
          (#t
           `(ar-apply ,afn (list ,@aargs))))))))
That one is not crucial, as it only brings a minor performance gain in most of the cases. However, I'm more skeptical about that :

  (define (ac-fn args body env)
   (if (ac-complex-args? args)
      (ac-complex-fn args body env)
      `(lambda ,(let ((a (ac-denil args))) (if (eqv? a 'nil) '() a))
         'nil
         ,@(ac-body body (append (ac-arglist args) env)))))
Versus the code from Anarki, still the original arc1's version :

  (define (ac-fn args body env)
   (if (ac-complex-args? args)
      (ac-complex-fn args body env)
      `(lambda ,(let ((a (ac-denil args))) (if (eqv? a 'nil) '() a))
         ,@(ac-body* body (append (ac-arglist args) env)))))
Isn't it a bug fix ? The one someone told about, with '(), () and nil not being always equivalent ? If so, that's more problematic. I tried to merge these codes together, but it was obviously broken and was reverted later in the git.

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5 points by nex3 6147 days ago | link

Those do seem to be mistakes. It looks like this might have been caused by the Windows-newlining of ac.scm, which screwed with the Git history a little. I'll change these to the arc2 versions... if you see any other inconsistencies, let me know.

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2 points by nex3 6146 days ago | link

I've changed ac-call to the arc2 version, but I think you're wrong about ac-fn. The following:

  (define (ac-fn args body env)
   (if (ac-complex-args? args)
      (ac-complex-fn args body env)
      `(lambda ,(let ((a (ac-denil args))) (if (eqv? a 'nil) '() a))
         'nil
         ,@(ac-body body (append (ac-arglist args) env)))))
is how it's been in arc0, arc1, and arc2. The following:

  (define (ac-fn args body env)
   (if (ac-complex-args? args)
      (ac-complex-fn args body env)
      `(lambda ,(let ((a (ac-denil args))) (if (eqv? a 'nil) '() a))
         ,@(ac-body* body (append (ac-arglist args) env)))))
is unique to Anarki, and was added as part of a patch for MzScheme compatibility.

After getting rid of all the trailing-whitespace-removal that was clogging the diffs, I think ac-call was the only non-purposeful difference between ac.scm in Anarki and arc2. Let me know if you notice any more, though.

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