/usr/share/racket/pkgs/swindle/patterns.rkt is in racket-common 6.7-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 | #lang mzscheme
(provide (all-from-except mzscheme
define-values
define
let-values
let*-values
letrec-values
let
let*
letrec
set!
set!-values
lambda))
(provide (rename define-values~ define-values)
(rename define~ define)
(rename let-values~ let-values)
(rename let*-values~ let*-values)
(rename letrec-values~ letrec-values)
(rename let~ let)
(rename let*~ let*)
(rename letrec~ letrec)
(rename set!~ set!)
(rename set!-values~ set!-values)
(rename lambda~ lambda))
(define-syntaxes (define-values~
define~
let-values~
let*-values~
letrec-values~
let~
let*~
letrec~
set!~
set!-values~
lambda~)
(let ()
(define (id->handlers id)
(and (identifier? id)
(syntax-local-value
(datum->syntax-object id
(string->symbol
(string-append "extended-arg-keyword:"
(symbol->string
(syntax-e id))))
id)
(lambda () #f))))
(define (flatten-extended-bindings/values stxs expr)
(define temps (generate-temporaries stxs))
(define (remove-false-2nd l)
(let loop ([l l] [r '()])
(if (null? l)
(reverse r)
(loop (cdr l) (if (cadar l) (cons (car l) r) r)))))
(let loop (;; tail: listof (cons extended-id, assigned-temp)
[tail (map cons (syntax->list stxs) temps)]
;; r: listof (list extended-ids new-temps convert-expr)
;; or (list extended-id same-temp #f)
[r '()]
;; #f if non-id scanned, otherwise #t or 'first on first pass
[simple? 'first]
;; vbinds: listof listof listof (vars expr)
[vbinds (list (list (list temps expr)))])
(if (null? tail)
(let ([r (reverse r)])
(if simple?
(if (eq? simple? 'first)
(values stxs expr)
(values (datum->syntax-object stxs (map car r) stxs)
(let loop ([vbs (reverse vbinds)])
(if (null? vbs)
(if (and (pair? r) (null? (cdr r)))
(quasisyntax/loc stxs #,(cadar r))
(quasisyntax/loc stxs (values #,@(map cadr r))))
(quasisyntax/loc stxs
(let-values #,(remove-false-2nd (car vbs))
#,(loop (cdr vbs))))))))
;; saw non-identifiers, so start another iteration
(loop (apply append (map (lambda (x)
(if (caddr x)
(map cons (car x) (cadr x))
(list (cons (car x) (cadr x)))))
r))
'() #t (cons (map cdr r) vbinds))))
(syntax-case (caar tail) ()
[var (identifier? #'var)
(loop (cdr tail) (cons (list (caar tail) (cdar tail) #f) r)
simple? vbinds)]
[(id . xs) (identifier? #'id)
(cond
[(id->handlers #'id) =>
(lambda (handlers)
(let ([bindings (syntax->list ((car handlers) #'xs))]
[new-expr ((cadr handlers) (cdar tail) #'xs)])
(unless (list? bindings)
(error 'extended-binding
"`~s->bindings' returned a non-list value: ~s"
(syntax-e #'id) bindings))
(loop (cdr tail)
(cons (list bindings (generate-temporaries bindings)
new-expr)
r)
#f vbinds)))]
[else (raise-syntax-error
'extended-binding
"got a form which is not an extended binding"
(caar tail) #'id)])]
[_ (raise-syntax-error
'extended-binding "bad binding" (caar tail))]))))
(define (_define-values stx)
(syntax-case stx ()
[(_ (var ...) expr)
(let-values ([(bindings expr)
(flatten-extended-bindings/values #'(var ...) #'expr)])
(quasisyntax/loc stx (define-values #,bindings #,expr)))]))
(define (_define stx)
(syntax-case stx (values)
[(_ (values x ...) expr)
(syntax/loc stx (define-values~ (x ...) expr))]
[(_ (id . xs) expr) (id->handlers #'id)
(syntax/loc stx (define-values~ ((id . xs)) expr))]
[(_ (id . xs) body0 body ...)
(syntax/loc stx (define-values~ (id) (lambda~ xs body0 body ...)))]
[(_ x expr)
(syntax/loc stx (define-values~ (x) expr))]))
(define (make-let-values let-form)
(lambda (stx)
(syntax-case stx ()
[(_ (binding ...) body0 body ...)
(quasisyntax/loc stx
(#,let-form
#,(map (lambda (binding)
(syntax-case binding ()
[((var ...) expr)
(let-values ([(bindings expr)
(flatten-extended-bindings/values
#'(var ...) #'expr)])
(quasisyntax/loc binding
(#,bindings #,expr)))]))
(syntax->list #'(binding ...)))
body0 body ...))])))
(define _let-values (make-let-values #'let-values))
(define _let*-values (make-let-values #'let*-values))
(define _letrec-values (make-let-values #'letrec-values))
(define (make-let let-form label?)
(lambda (stx)
(syntax-case stx ()
[(_ label ((var val) ...) body0 body ...)
(and label? (identifier? #'label))
(quasisyntax/loc stx
((letrec~ ([label (lambda~ (var ...) body0 body ...)]) label)
val ...))]
[(_ (binding ...) body0 body ...)
(quasisyntax/loc stx
(#,let-form #,(map (lambda (binding)
(syntax-case binding (values)
[((values x ...) expr) #'((x ...) expr)]
[(x expr) #'((x) expr)]))
(syntax->list #'(binding ...)))
body0 body ...))])))
(define _let (make-let #'let-values~ #t))
(define _let* (make-let #'let*-values~ #f))
(define _letrec (make-let #'letrec-values~ #f))
(define (_set! stx)
(syntax-case stx (values)
[(_ (values x ...) expr) (syntax/loc stx (set!-values~ (x ...) expr))]
[(_ x expr) (syntax/loc stx (set!-values~ (x) expr))]))
(define (_set!-values stx)
(syntax-case stx ()
[(_ (var ...) expr)
(let-values ([(bindings expr)
(flatten-extended-bindings/values #'(var ...) #'expr)])
(quasisyntax/loc stx
(set!-values #,bindings #,expr)))]))
(define (_lambda stx)
(syntax-case stx ()
[(_ vars body0 body ...)
(let loop ([vs #'vars] [newvars '()] [specials '()] [restarg '()])
(syntax-case vs ()
[((id xs ...) . rest) (identifier? #'id)
(let ([newvar (car (generate-temporaries #'(id)))])
(loop #'rest (cons newvar newvars)
(cons (list #'(id xs ...) newvar) specials)
restarg))]
[(id . rest) (identifier? #'id)
(loop #'rest (cons #'id newvars) specials restarg)]
[id (identifier? #'id)
(loop #'() newvars specials #'id)]
[() (let ([args (datum->syntax-object
#'vars (append (reverse newvars) restarg)
#'vars)])
(if (null? specials)
(quasisyntax/loc stx (lambda #,args body0 body ...))
(quasisyntax/loc stx
(lambda #,args
(let~ #,(reverse specials)
body0 body ...)))))]))]))
(values _define-values
_define
_let-values
_let*-values
_letrec-values
_let
_let*
_letrec
_set!
_set!-values
_lambda)))
;; These are used as procedures for the syntax level
(provide extended-arg-keyword:list extended-arg-keyword:vector)
(define-syntax extended-arg-keyword:list
(list (lambda (vars) vars)
(lambda (expr vars)
(quasisyntax/loc expr (apply values #,expr)))))
(define-syntax extended-arg-keyword:vector
(list (lambda (vars) vars)
(lambda (expr vars)
(quasisyntax/loc expr (apply values (vector->list #,expr))))))
;; quote turns implicit lists and vectors to explicit ones
(provide extended-arg-keyword:quote)
(define-syntax extended-arg-keyword:quote
(list (lambda (vars)
(define (do-vars vs)
(datum->syntax-object
vs (map (lambda (v)
(if (identifier? v) v (quasisyntax/loc v '#,v)))
(syntax->list vs))
vs))
(do-vars (syntax-case vars ()
[((v ...)) #'(v ...)] [(#(v ...)) #'(v ...)])))
(lambda (expr vars)
(syntax-case vars ()
[((v ...))
(quasisyntax/loc expr (apply values #,expr))]
[(#(v ...))
(quasisyntax/loc expr (apply values (vector->list #,expr)))]))))
;; (define (values a (list (vector b c) (vector d) (list)) e)
;; (values 1 (list (vector 2 3) (vector 4) (list)) 5))
;; (list a b c d e)
;; (let ([(values a (list (vector b c) (vector d) (list)) e)
;; (values 1 (list (vector 2 3) (vector 4) (list)) 5)])
;; (list a b c d e))
;; (let* ([(list x y) (list 1 2)] [(list x y) (list y x)]) (list x y))
;; (let ([(values a '(#(b c) #(d) ()) e)
;; (values 1 '(#(2 3) #(4) ()) 5)])
;; (list a b c d e))
;; (map (lambda ((list x y)) (list y x)) '((1 2) (3 4)))
;; (let loop ([(list str n) (list "foo" 10)])
;; (if (zero? n) str (loop (list (string-append str "!") (sub1 n)))))
;;
;; (module foo mzscheme
;; (provide (struct point (x y)) extended-arg-keyword:make-point)
;; (define-struct point (x y))
;; (define-syntax extended-arg-keyword:make-point
;; (list (lambda (vars) (syntax-case vars () ((x y) vars)))
;; (lambda (expr vars)
;; (quasisyntax/loc expr
;; (values (point-x #,expr) (point-y #,expr)))))))
;; (require foo)
;; (define a (make-point 1 2))
;; (let ([(make-point x y) a]) (+ x y))
|