Re: [Jscheme-user] definitions available at compile time?

[Kyle R. B. <kyl...@gm...>]

> I'm getting an error that seems to indicate the compiler can't see my
> toplevel function definitions during macroexpansion. I have a function foo,
> and a macro M that uses it. I get an error compiling function bar, which
> uses M, saying undefined variable "foo". How can I make my definitions
> visible during compilation?
> Example code that exhibits this issue:
> (define (foo x) (+ 1 x))
> (define-macro (M y) (foo y))
> (define (bar z) (M 3))
>
> output:
> first pass of compiler
> (compiling  foo)
> (compiling  bar)
> (Error while compiling  SchemeException: ERROR: undefined variable "foo")
> SchemeException: ERROR: undefined variable "foo"
>         at jsint.E.error(E.java:14)
>
> thank you, and thank you for JScheme, which I am greatly enjoying!!

Do you want foo to be part of the expansoin?  In other words, do you
want M to expand to the call to foo, or do you want it to be 'compiled
away'?

eg, do you want bar to be equivalent to:

 (define (bar z) (foo 3))

Or do you want it to be

 (define (bar z) 4)

?

If it is the former, then M should probably look like:

  (define-macro (M y) `(foo ,y))

Either way, when I type in your expressions, I receive no error with
jscheme 7.2:

$ java -jar jscheme-7.2.jar
JScheme 7.2 (2/2/06 9:47 PM) http://jscheme.sourceforge.net
> (define (foo x) (+ 1 x))
$1 = (lambda foo (x)...)
> (foo 3)
$2 = 4
> (define-macro (M y) (foo y))
$3 = (macro M (y)...)
> (define (bar z) (M 3))
$4 = (lambda bar (z)...)
> (bar 1)
$5 = 4
> (bar 2)
$6 = 4
>

If you're after constant math (making bar be the integer 4), actually
regardless, it looks like if you put the macro definition in a
separate file and load it, it succeeds:

$ cat mac.scm
(define-macro (M y) (foo y))

kburton@lap0029 ~/projects/sandbox/jscheme
$ cat Foo.scm
(load "mac.scm")
(define (foo x) (+ 1 x))
(define (bar z) (M 3))

(define (main args)
  (write "bar ") (write (bar 10)) (newline))

I'm not very familiar with the compiler...I hope this helps.

Regards,

Kyle Burton