Re: [Axiom-developer] lisp -> spad question

[Waldek Hebisch]

Arthur Ralfs wrote:
> Hello,
> 
> The following lisp seems to do what I want, i.e. capture stuff written to
> *standard-output* in a string,
> 
> (1) -> )lisp (setq out (with-output-to-string (*standard-output*)
> (write-line "hello universe")))
> (1) ->
> Value = "hello universe
> "
> (1) -> )lisp (write-line out)
> hello universe
> 
> Value = "hello universe
> "
> 
> However when I try to translate this to spad with the following function:
> 
>     testCommand2():Void ==
>        
> SETQ(out$Lisp,WITH_-OUTPUT_-TO_-STRING(LIST(_*STANDARD_-OUTPUT_*$Lisp)$Lisp,
>             WriteLine("Hello Universe")$Lisp)$Lisp)$Lisp
> 
> 
> I get this:
> 
> (1) -> testCommand2()
>    Loading /home/arthur/axiom/silver/silver-07-08-25/AXSERV.nrlib/code
>       for package AxiomServer
> 
>    >> System error:
>    #<synonym stream to *TERMINAL-IO*> is not a string with a fill-pointer.
> 
> Can anybody tell me what's going on?
> 

Your Spad code corresponds to:

(setq out (with-output-to-string (list *standard-output*)
          (write-line "hello universe")))

which wants *standard-output* to be a string with fill pointer
(and list would be the resulting stream).  To get your Lisp
you need something like:

SETQ(out$Lisp,WITH_-OUTPUT_-TO_-STRING(_*STANDARD_-OUTPUT_*()$Lisp)$Lisp,
             WriteLine("Hello Universe")$Lisp)$Lisp)$Lisp

(which IMHO is extremally ugly).

I would say that it if you need things like with-output-to-string than
it is better to write your function in Lisp -- Spad version is
impossible to understand without knowing Lisp and a Lisper will
still have trouble translating Spad syntax to Lisp.

-- 
                              Waldek Hebisch
address@hidden