Le vendredi 2 septembre 2016 12:32:52 UTC+2, Jack Firth a écrit :
> However, (parameterize ([param tool-func]) (dynamic-require mod-path))
> doesn't seem to work because the parameter is being set for the runtime phase
> rather than the expansion time phase.
Here's a solution, which also allows the mod-path to return a value, but it
must do so at compile-time (I think the run-time is not even executed).
param.rkt:
#lang racket
(provide foo)
(define foo (make-parameter #f))
mod-path.rkt:
#lang racket
(require (for-meta 1 "param.rkt"))
(provide (for-syntax return-value))
(define-for-syntax return-value `("here's my report: " (foo is ,(foo))))
(provide (for-syntax varref))
(define-for-syntax varref (#%variable-reference))
tool.rkt:
#lang racket
(require (for-meta 1 "param.rkt"))
(define run-time-param-value (+ 40 2))
(define run-time-module-name (string-append "mod" "-path.rkt"))
(define result
(eval #`(begin
(define-syntax (trampoline _stx)
(parameterize ([foo #,run-time-param-value])
(define ns
(eval '(begin
(require (for-template #,run-time-module-name))
(variable-reference->namespace varref))))
#`#,(namespace-variable-value 'varref #f #f ns)))
(define varref-0 (trampoline))
(define ns-0 (variable-reference->namespace varref-0))
(parameterize ([current-namespace ns-0])
(namespace-variable-value 'return-value)))))
result
After our discussion on IRC:
> …
> @notjack: IIUC, your tool expands 'mod, and wants to access the syntax
> properties of the expanded code?
> <notjack> yup, exactly
> …
it seems something like this would be more suited to your purposes:
mod-path.rkt:
#lang racket
(define-syntax (mod-stx stx)
(syntax-property #'42
'my-prop 123))
(mod-stx)
tool.rkt:
#lang racket
(define (traverse stx)
(when (and (syntax? stx) (syntax-property stx 'my-prop))
(displayln (syntax-property stx 'my-prop)))
(cond
[(syntax? stx) (traverse (syntax-e stx))]
[(list? stx) (map traverse stx)]
[(pair? stx) (traverse (car stx))
(traverse (cdr stx))]
[(vector? stx) (traverse (vector->list stx))]
[(prefab-struct-key stx) (traverse (struct->vector stx))])
(void))
(traverse
(parameterize ([read-accept-lang #t]
[current-namespace (make-base-namespace)])
(expand-syntax
(namespace-syntax-introduce
(read-syntax "tool.rkt" (open-input-file "tool.rkt"))))))
;; => 123
;; 123
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