PATCH: Handle symbols in messages

[Doug Evans]

fwiw, while string-concat might not clearly specify the operation
(though I don't have a problem with it), `concat' seems too generic
(or at least not string-specific enough in the way that the rest of
the string functions are so named).

string-map is to map,
as string-list is to list,
as string-<mumble> is to concat.

concat mightn't make sense outside of strings (and thus why have the
string- prefix ...), but why preclude symbol-concat? (etc.)

How about string-concat?

 > diff -c -p -r1.82 utils.scm
 > *** cgen/utils.scm	16 Dec 2004 21:52:37 -0000	1.82
 > --- cgen/utils.scm	20 Jan 2005 22:52:04 -0000
 > ***************
 > *** 85,90 ****
 > --- 85,96 ----
 >       (write (spaces n) port))
 >   )
 >   
 > + ; Concatenate all the arguments and make a string.  Symbols are
 > + ; converted to strings.
 > + (define (concat . sequences)
 > +   (define (sequence->string o) (if (symbol? o) (symbol->string o) o))
 > +   (apply string-append (map sequence->string sequences)))
 > + 
 >   ; Often used idiom.
 >   
 >   (define (string-map fn . args) (apply string-append (apply map (cons fn args))))