144 lines
5.9 KiB
Scheme
144 lines
5.9 KiB
Scheme
#lang scheme/base
|
|
(require (for-syntax scheme/base
|
|
syntax/kerncase)
|
|
"stxparam.ss"
|
|
"private/stxparam.ss")
|
|
|
|
(provide splicing-let-syntax
|
|
splicing-let-syntaxes
|
|
splicing-letrec-syntax
|
|
splicing-letrec-syntaxes
|
|
splicing-syntax-parameterize)
|
|
|
|
(define-for-syntax (do-let-syntax stx rec? multi? let-stx-id)
|
|
(syntax-case stx ()
|
|
[(_ ([ids expr] ...) body ...)
|
|
(let ([all-ids (map (lambda (ids-stx)
|
|
(let ([ids (if multi?
|
|
(syntax->list ids-stx)
|
|
(list ids-stx))])
|
|
(unless ids
|
|
(raise-syntax-error
|
|
#f
|
|
"expected a parenthesized sequence of identifiers"
|
|
stx
|
|
ids-stx))
|
|
(for-each (lambda (id)
|
|
(unless (identifier? id)
|
|
(raise-syntax-error
|
|
#f
|
|
"expected an identifier"
|
|
stx
|
|
id)))
|
|
ids)
|
|
ids))
|
|
(syntax->list #'(ids ...)))])
|
|
(let ([dup-id (check-duplicate-identifier
|
|
(apply append all-ids))])
|
|
(when dup-id
|
|
(raise-syntax-error
|
|
#f
|
|
"duplicate binding"
|
|
stx
|
|
dup-id)))
|
|
(if (eq? 'expression (syntax-local-context))
|
|
(with-syntax ([let-stx let-stx-id])
|
|
(syntax/loc stx
|
|
(let-stx ([ids expr] ...)
|
|
(#%expression body)
|
|
...)))
|
|
(let ([def-ctx (syntax-local-make-definition-context)]
|
|
[ctx (list (gensym 'intdef))])
|
|
(syntax-local-bind-syntaxes (apply append all-ids) #f def-ctx)
|
|
(internal-definition-context-seal def-ctx)
|
|
(let* ([add-context
|
|
(lambda (expr)
|
|
(let ([q (local-expand #`(quote #,expr)
|
|
ctx
|
|
(list #'quote)
|
|
def-ctx)])
|
|
(syntax-case q ()
|
|
[(_ expr) #'expr])))])
|
|
(with-syntax ([((id ...) ...)
|
|
(map (lambda (ids)
|
|
(map add-context ids))
|
|
all-ids)]
|
|
[(expr ...)
|
|
(let ([exprs (syntax->list #'(expr ...))])
|
|
(if rec?
|
|
(map add-context exprs)
|
|
exprs))]
|
|
[(body ...)
|
|
(map add-context (syntax->list #'(body ...)))])
|
|
#'(begin
|
|
(define-syntaxes (id ...) expr)
|
|
...
|
|
body ...))))))]))
|
|
|
|
(define-syntax (splicing-let-syntax stx)
|
|
(do-let-syntax stx #f #f #'let-syntax))
|
|
|
|
(define-syntax (splicing-let-syntaxes stx)
|
|
(do-let-syntax stx #f #t #'let-syntaxes))
|
|
|
|
(define-syntax (splicing-letrec-syntax stx)
|
|
(do-let-syntax stx #t #f #'letrec-syntax))
|
|
|
|
(define-syntax (splicing-letrec-syntaxes stx)
|
|
(do-let-syntax stx #t #t #'letrec-syntaxes))
|
|
|
|
;; ----------------------------------------
|
|
|
|
(define-syntax (splicing-syntax-parameterize stx)
|
|
(if (eq? 'expression (syntax-local-context))
|
|
;; Splicing is no help in an expression context:
|
|
(do-syntax-parameterize stx #'let-syntaxes)
|
|
;; Let `syntax-parameterize' check syntax, then continue
|
|
(do-syntax-parameterize stx #'ssp-let-syntaxes)))
|
|
|
|
(define-syntax (ssp-let-syntaxes stx)
|
|
(syntax-case stx ()
|
|
[(_ ([(id) rhs] ...) body ...)
|
|
(with-syntax ([(splicing-temp ...) (generate-temporaries #'(id ...))])
|
|
#'(begin
|
|
;; Evaluate each RHS only once:
|
|
(define-syntax splicing-temp rhs) ...
|
|
;; Partially expand `body' to push down `let-syntax':
|
|
(expand-ssp-body (id ...) (splicing-temp ...) body)
|
|
...))]))
|
|
|
|
(define-syntax (expand-ssp-body stx)
|
|
(syntax-case stx ()
|
|
[(_ (sp-id ...) (temp-id ...) body)
|
|
(let ([body (local-expand #'(letrec-syntaxes ([(sp-id) (syntax-local-value (quote-syntax temp-id))]
|
|
...)
|
|
(force-expand body))
|
|
(syntax-local-context)
|
|
null ;; `force-expand' actually determines stopping places
|
|
#f)])
|
|
;; Extract expanded body out of `body':
|
|
(syntax-case body (quote)
|
|
[(ls _ _ (quoute body))
|
|
(let ([body #'body])
|
|
(syntax-case body (begin define-values define-syntaxes define-for-syntaxes)
|
|
[(define-values (id ...) rhs)
|
|
(syntax/loc body
|
|
(define-values (id ...)
|
|
(letrec-syntaxes ([(sp-id) (syntax-local-value (quote-syntax temp-id))] ...)
|
|
rhs)))]
|
|
[(define-syntaxes . _) body]
|
|
[(define-for-syntaxes . _) body]
|
|
[expr (syntax/loc body
|
|
(letrec-syntaxes ([(sp-id) (syntax-local-value (quote-syntax temp-id))] ...)
|
|
expr))]))]))]))
|
|
|
|
(define-syntax (force-expand stx)
|
|
(syntax-case stx ()
|
|
[(_ stx)
|
|
;; Expand `stx' to reveal type of form, and then preserve it via
|
|
;; `quote':
|
|
#`(quote #,(local-expand #'stx
|
|
'module
|
|
(kernel-form-identifier-list)
|
|
#f))]))
|