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Black Hole
by Marcelo Alvim 17 Aoû '09

17 Aoû '09

Hi, I am new to Gambit (and Scheme as a whole), and I'm trying to install Black Hole with no success so far. I've tried following the instructions in http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Black_Hole, but whenever I try to clone http://mwaza.dyndns.org/apps/files/modules.git I get a timeout. If I try git://repo.or.cz/blackhole.git I get an empty repo. Does anyone know if Black Hole is still going and, if so, where to get it? Thanks, Marcelo.

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Gambit in Emacs: REPL interaction
by FFT 17 Aoû '09

17 Aoû '09

Hi I tried to use Emacs as suggested in the manual, and I also tried the Quack mode. Either I'm not using them right, or they just don't provide the functionality I need. I'm not looking for something as advanced as SLIME necessarily (which AFAIK only works with Scheme48), but at least something like what you get with ELISP: When you are editing a file, and eval an expression to the REPL, you get an answer in the minibuffer (which should temporarily expand if necessary) Also, if there is an error, you get a kind of pop-up window that's easy to dismiss and get to the top level of the REPL. I don't get these with Quack or Gambit mode. How do you make this work with Emacs? Commercial IDEs ruined this for me.

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macro vs runtime environment
by lowly coder 15 Aoû '09

15 Aoû '09

why is: (load "t1.scm") (define x 20) valid, where as: (define-macro (foo) (load "t1.scm") (define x 20)) result in a ill-placed define error? I was under the impression that scheme define-macro was just scheme code; it appears that the environment the macro is run in is different from the runtime ones? Thanks!

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Re: [gambit-list] Video game written in Gambit
by David Rush 15 Aoû '09

15 Aoû '09

ummm....I found a bug :) in action mode spin the cube so fast that the quantz all remain floating while a new quantz comes in. I eventually ended up with a stuck sprite in the middle of the screen... -- GPG Public key at http://cyber-rush.org/drr/gpg-public-key.txt

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why does load/include work differently for this function?
by lowly coder 15 Aoû '09

15 Aoû '09

~/test:$ cat lookup-var.scm (define (lookup-var var-name) (##define-macro (macro-code-cte c) `(##vector-ref ,c 2)) (##define-macro (macro-rte-up rte) `(##vector-ref ,rte 0)) (define (the-env) (##continuation-capture (lambda (cont) (if (##interp-continuation? cont) (let (($code (##interp-continuation-code cont)) (rte (##interp-continuation-rte cont))) (cons (macro-code-cte $code) rte)) (error "the-env must be called from interpreted code"))))) (define (env-ref env var) (let loop1 ((c (car env)) (r (cdr env))) (cond ((##cte-top? c) (##global-var-ref (##make-global-var var))) ((##cte-frame? c) (let loop2 ((vars (##cte-frame-vars c)) (i 1)) (if (pair? vars) (if (eq? var (##car vars)) (vector-ref r i) (loop2 (cdr vars) (+ i 1))) (loop1 (##cte-parent-cte c) (macro-rte-up r))))) (else (loop1 (##cte-parent-cte c) r))))) (env-ref (the-env) var-name)) ~/test:$ cat test.scm (define-macro (foo) (define x 20) (load "./lookup-var") (pp `(foo ,(lookup-var 'x)))) (define-macro (bar) (define x 20) (include "./lookup-var.scm") (pp `(bar ,(lookup-var 'x)))) (foo) (bar) ~/test:$ gsi test.scm (foo #!unbound) (bar 20) note that lookup-var is just a function ... i'm surprised that load/include gives me different results

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.gambcini vs included files
by lowly coder 15 Aoû '09

15 Aoû '09

~/test:$ cat ../.gambcini (define-macro (bar#fun2 foo) ''(yay)) (pp 'loaded-gambcini) ~/test:$ cat test.scm (define-macro (bar#fun x) (if (equal? x cons) 1 2)) (##namespace ("foo#")) (##namespace ("" pp load)) (pp (bar#fun '+)) (load "t1.scm") ~/test:$ cat t1.scm (pp (bar#fun2 '-)) (pp (bar#fun '-)) ~/test:$ gsi test.scm loaded-gambcini 2 (yay) *** ERROR IN "t1.scm"@2.6 -- Unbound variable: bar#fun ~/test:$ Here's what confuses me -- the macro defined in ~/.gambcini is accessible, but the one in test.scm is not. What 'environment' are the functions/macros in ~/.gambcini defined in? [And how can I at run time throw stuff in there]. Thanks!

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syntax-case and keywords
by Derrell Piper 15 Aoû '09

15 Aoû '09

Hi, I'm porting some Lisp to Scheme and I've run into a problem trying to use both extended parameter lists (keywords) with syntax-case. % cat test.scm (define (s #!key (f "foo") (v #f)) #t) % gsi test % gsi -e '(load "~~lib/syntax-case")' test *** ERROR IN ##call-with-values -- invalid syntax (define (s #!key (f "foo") (v #f)) #t) The actual code has both define-syntax and define-macro definitions. The manual says that define-syntax doesn't support special forms that are specific to Gambit, so I'm assuming that's the real issue here. But I'm wondering what the philosophy of Gambit is with respect to macros, given that define-syntax was specified for both R4RS and R5RS. Chicken 4 deprecated the use of define-macro and now forces one to use define-syntax. Which is ironically why I have define-syntax forms, in that I ported this code to Chicken first. Should I just rewrite them as define-macro? For all it's faults, CL only has one macro form. :-)

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Retrieving both key and value from table
by Alex Queiroz 14 Aoû '09

14 Aoû '09

Hallo, In a table I am using keys which are structures defined with define-type. Since some of the fields have the equality-skip: modifier, the key that I pass is not the same as the key stored in the table. I have taken a look in sys.scm and it seems I could hack a solution using ##table-access. Is this the best way to do this? I could also store a pair as the associated value in the hash table, but I'd like to avoid consing. Speaking about consing, is there a way to limit the growth of the hash table to a certain bound? Thanks, -- -alex http://www.ventonegro.org/

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macro tricks
by lowly coder 14 Aoû '09

14 Aoû '09

(define-macro (foo) (define x 20) (define (magic-func var-name) ...) (pp (magic-func 'x))) (foo) Is there anyway I can define magic-func so that 20 is outputted?

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macro problems
by lowly coder 13 Aoû '09

13 Aoû '09

(define foo 2) (pp (eval 'foo)) (define-macro (test) (define bar 3) (pp (eval 'bar))) ;(test) why does (test) fail? it confuses me why the eval works in foo but not in bar Thanks!

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