Re: More GUILE for LilyPond

[Russ McManus <russell.mcmanus@gs.com>]

Han-Wen Nienhuys <hanwen@cs.uu.nl> writes:

> I am still muddling along with integrating GUILE in LilyPond, and I
> have a question.  I want to replace an existing C++ implementation of
> identifier tables by GUILE's code.  I've managed to replace
> 
> 	Hash_table<String,Identifier*>
> 
> by
> 
> 	Hash_table<SCM, Identifier*>
> 
> and use interning and GUILE symbols for doing the identifier lookup.
> But I'd like to use GUILE's hash tables as well, and that's were my
> question comes in: is there an interface that allows me to iterate
> through the entries of a GUILE hash table?

I use the following, which should definitely be provided somewhere
in guile, but isn't, AFAIK:

(define (hash-table-for-each fn ht)
  (do ((i 0 (+ 1 i)))
      ((= i (vector-length ht)))
    (do ((alist (vector-ref ht i) (cdr alist)))
	((null? alist) #t)
      (fn (car (car alist)) (cdr (car alist))))))

(define (hash-table-map fn ht)
  (do ((i 0 (+ 1 i))
       (ret-ls '()))
      ((= i (vector-length ht)) (reverse ret-ls))
    (do ((alist (vector-ref ht i) (cdr alist)))
	((null? alist) #t)
      (set! ret-ls (cons (fn (car (car alist)) (cdr (car alist))) ret-ls)))))

If you want a C version, you can run the above code through hobbit, or
tranlate it to C by hand.

-russ


--
"Whenever you find yourself on the side of the majority, it is time to
pause and reflect."
             -- Mark Twain