ikarus/scheme/ikarus.symbols.ss

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;;; Ikarus Scheme -- A compiler for R6RS Scheme.
;;; Copyright (C) 2006,2007,2008 Abdulaziz Ghuloum
;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License version 3 as
;;; published by the Free Software Foundation.
;;;
;;; This program is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(library (ikarus.symbols)
(export gensym gensym? gensym->unique-string gensym-prefix
gensym-count print-gensym string->symbol symbol->string
getprop putprop remprop property-list
top-level-value top-level-bound? set-top-level-value!
symbol-value symbol-bound? set-symbol-value!
reset-symbol-proc! system-value system-value-gensym)
(import
(ikarus system $symbols)
(ikarus system $pairs)
(ikarus system $fx)
(except (ikarus) gensym gensym? gensym->unique-string
gensym-prefix gensym-count print-gensym system-value
string->symbol symbol->string
getprop putprop remprop property-list
top-level-value top-level-bound? set-top-level-value!
symbol-value symbol-bound? set-symbol-value! reset-symbol-proc!))
(define gensym
(case-lambda
[() ($make-symbol #f)]
[(s)
(if (string? s)
($make-symbol s)
(if (symbol? s)
($make-symbol ($symbol-string s))
(die 'gensym "neither a string nor a symbol" s)))]))
(define gensym?
(lambda (x)
(and (symbol? x)
(let ([s ($symbol-unique-string x)])
(and s #t)))))
(define top-level-value
(lambda (x)
(unless (symbol? x)
(die 'top-level-value "not a symbol" x))
(let ([v ($symbol-value x)])
(when ($unbound-object? v)
(die 'eval "unbound variable"
(string->symbol
(symbol->string x))))
v)))
(define top-level-bound?
(lambda (x)
(unless (symbol? x)
(die 'top-level-bound? "not a symbol" x))
(not ($unbound-object? ($symbol-value x)))))
(define set-top-level-value!
(lambda (x v)
(unless (symbol? x)
(die 'set-top-level-value! "not a symbol" x))
($set-symbol-value! x v)))
(define symbol-value
(lambda (x)
(unless (symbol? x)
(die 'symbol-value "not a symbol" x))
(let ([v ($symbol-value x)])
(when ($unbound-object? v)
(die 'symbol-value "unbound" x))
v)))
(define symbol-bound?
(lambda (x)
(unless (symbol? x)
(die 'symbol-bound? "not a symbol" x))
(not ($unbound-object? ($symbol-value x)))))
(define set-symbol-value!
(lambda (x v)
(unless (symbol? x)
(die 'set-symbol-value! "not a symbol" x))
($set-symbol-value! x v)
($set-symbol-proc! x
(if (procedure? v) v
(lambda args
(die 'apply "not a procedure"
($symbol-value x)))))))
(define reset-symbol-proc!
(lambda (x)
(let ([v ($symbol-value x)])
($set-symbol-proc! x
(if (procedure? v)
v
(lambda args
(let ([v ($symbol-value x)])
(if ($unbound-object? v)
(die 'eval "unbound variable"
(string->symbol
(symbol->string x)))
(die 'apply "not a procedure" v)))))))))
(define string->symbol
(lambda (x)
(unless (string? x)
(die 'string->symbol "not a string" x))
(foreign-call "ikrt_string_to_symbol" x)))
(define symbol->string
(lambda (x)
(unless (symbol? x)
(die 'symbol->string "not a symbol" x))
(let ([str ($symbol-string x)])
(or str
(let ([ct (gensym-count)])
;;; FIXME: what if gensym-count is a bignum?
(let ([str (string-append (gensym-prefix) (fixnum->string ct))])
($set-symbol-string! x str)
(gensym-count ($fxadd1 ct))
str))))))
(define putprop
(lambda (x k v)
(unless (symbol? x) (die 'putprop "not a symbol" x))
(unless (symbol? k) (die 'putprop "not a symbol" k))
(let ([p ($symbol-plist x)])
(cond
[(assq k p) => (lambda (x) (set-cdr! x v))]
[else
($set-symbol-plist! x (cons (cons k v) p))]))))
(define getprop
(lambda (x k)
(unless (symbol? x) (die 'getprop "not a symbol" x))
(unless (symbol? k) (die 'getprop "not a symbol" k))
(let ([p ($symbol-plist x)])
(cond
[(assq k p) => cdr]
[else #f]))))
(define remprop
(lambda (x k)
(unless (symbol? x) (die 'remprop "not a symbol" x))
(unless (symbol? k) (die 'remprop "not a symbol" k))
(let ([p ($symbol-plist x)])
(unless (null? p)
(let ([a ($car p)])
(cond
[(eq? ($car a) k) ($set-symbol-plist! x ($cdr p))]
[else
(let f ([q p] [p ($cdr p)])
(unless (null? p)
(let ([a ($car p)])
(cond
[(eq? ($car a) k)
($set-cdr! q ($cdr p))]
[else
(f p ($cdr p))]))))]))))))
(define property-list
(lambda (x)
(unless (symbol? x)
(die 'property-list "not a symbol" x))
(letrec ([f
(lambda (ls ac)
(cond
[(null? ls) ac]
[else
(let ([a ($car ls)])
(f ($cdr ls)
(cons ($car a) (cons ($cdr a) ac))))]))])
(f ($symbol-plist x) '()))))
(define gensym->unique-string
(lambda (x)
(unless (symbol? x)
(die 'gensym->unique-string "not a gensym" x))
(let ([us ($symbol-unique-string x)])
(cond
[(string? us) us]
[(not us)
(die 'gensym->unique-string "not a gensym" x)]
[else
(let f ([x x])
(let ([id (uuid)])
($set-symbol-unique-string! x id)
(cond
[(foreign-call "ikrt_intern_gensym" x) id]
[else (f x)])))]))))
(define gensym-prefix
(make-parameter
"g"
(lambda (x)
(unless (string? x)
(die 'gensym-prefix "not a string" x))
x)))
(define gensym-count
(make-parameter
0
(lambda (x)
(unless (and (fixnum? x) ($fx>= x 0))
(die 'gensym-count "not a valid count" x))
x)))
(define print-gensym
(make-parameter
#t
(lambda (x)
(unless (or (boolean? x) (eq? x 'pretty))
(die 'print-gensym "not in #t|#f|pretty" x))
x)))
(define system-value-gensym (gensym))
(define (system-value x)
(unless (symbol? x)
(die 'system-value "not a symbol" x))
(cond
[(getprop x system-value-gensym) =>
(lambda (g)
(let ([v ($symbol-value g)])
(when ($unbound-object? v)
(die 'system-value "not a system symbol" x))
v))]
[else (die 'system-value "not a system symbol" x)]))
)