auto-syntax-e/main.rkt
2016-10-20 01:43:49 +02:00

103 lines
3.5 KiB
Racket

#lang racket/base
(require racket/match
syntax/parse
(for-syntax racket/base
racket/syntax
racket/list
racket/struct
syntax/parse
racket/private/sc)
;; attribute-mapping? is provided for-syntax
(only-in syntax/parse/private/residual attribute-mapping?))
(provide auto-with-syntax)
(provide auto-syntax)
(provide auto-syntax-case)
(define (leaves->datum e depth)
(if (> depth 0)
(map (λ (eᵢ) (leaves->datum eᵢ (sub1 depth))) e)
(if (syntax? e)
(syntax->datum e)
e)))
(define-syntax (to-datum stx)
(syntax-case stx ()
[(_ id)
(syntax-pattern-variable? (syntax-local-value #'id (λ () #f)))
(begin
(let* ([mapping (syntax-local-value #'id)]
[valvar (syntax-mapping-valvar mapping)]
[depth (syntax-mapping-depth mapping)])
(if (attribute-mapping? (syntax-local-value valvar (λ () #f)))
#`(leaves->datum (attribute id) #,depth)
#`(leaves->datum #,valvar #,depth))))]))
(begin-for-syntax
(define-values (struct:auto-pvar
make-auto-pvar
auto-pvar?
auto-pvar-ref
auto-pvar-set!)
(make-struct-type 'auto-pvar
(eval #'struct:syntax-mapping
(module->namespace 'racket/private/sc))
0
0
#f
null
(current-inspector)
(λ (self stx)
#`(to-datum #,stx)))))
(define-for-syntax (syntax->tree/ids e)
(cond [(identifier? e) e]
[(syntax? e) (syntax->tree/ids (syntax-e e))]
[(pair? e) (cons (syntax->tree/ids (car e))
(syntax->tree/ids (cdr e)))]
[(vector? e) (map syntax->tree/ids (vector->list e))]
[(box? e) (syntax->tree/ids (unbox e))]
[(prefab-struct-key e) (map syntax->tree/ids (struct->list e))]
[else e]))
(define-for-syntax (syntax->ids e)
(filter identifier? (flatten (syntax->tree/ids e))))
(define-syntax auto-syntax
(syntax-parser
[(_ (id ...) body ...)
#:with (pvar-id ...) (filter (λ (id)
(syntax-pattern-variable?
(syntax-local-value id (λ () #f))))
(syntax->list #'(id ...)))
(with-disappeared-uses
(let ()
(record-disappeared-uses (syntax->list #'(pvar-id ...)))
#'(let-syntax ([pvar-id
(make-set!-transformer
(let ([mapping (syntax-local-value
(quote-syntax pvar-id))])
(make-auto-pvar (syntax-mapping-depth mapping)
(syntax-mapping-valvar mapping))))]
...)
body ...)))]))
(define-syntax auto-with-syntax
(syntax-parser
[(_ ([pat e] ...) body ...)
#:with (id ...) (syntax->ids #'(pat ...))
#'(with-syntax ([pat e] ...)
(auto-syntax (id ...)
body ...))]))
(define-syntax auto-syntax-case
(syntax-parser
[(_ stx-expression literals [pat guard+body ...] ...)
#:with (id ...) (syntax->ids #'(pat ...))
#'(syntax-case stx-expression literals
[pat (auto-syntax (id ...)
guard+body ...)]
...)]))