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;; This file is part of scheme-GNUnet, a partial Scheme port of GNUnet
;; scheme-GNUnet contains scheme-extractor.
;; scheme-extractor is a partial Scheme port of libextractor.
;; Copyright (C) 2020, 2021 Maxime Devos
;;
;; libextractor is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published
;; by the Free Software Foundation; either version 3, or (at your
;; option) any later version.
;;
;; libextractor 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 libextractor; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;; Brief: typed C-like enums
;; Features:
;; * typed
;; * integer and symbol conversion
;; * source line information (bug: isn't registered for some reason)
;; * docstrings
;; * enum values can be compared with eq?
;; (unless they aren't defined, in which
;; one must compare the indices directly,
;; or with value=?)
(define-library (gnu extractor enum)
(export value->index value->symbol value-dynamic?
value-documentation value-source
value-enum
enum-name enum-max-value enum-predefined-values
enum-source enum-docstring
integer->value symbol->value symbol-value
value enumeration define-enumeration
value=?)
(import (only (guile)
write newline display
syntax-source assq-ref compose
resolve-module module-ref
raise-exception)
(only (system syntax) syntax-local-binding)
(system vm program)
(ice-9 format)
(only (srfi srfi-9 gnu)
set-record-type-printer!)
(except (srfi srfi-1) map)
(srfi srfi-26)
(except (srfi srfi-43) vector-map)
(rnrs base)
;;map vector-map)
(rnrs control)
(rnrs syntax-case)
(rnrs records syntactic))
(begin
(define-record-type (<value> %make-value value?)
;; Numeric value
(fields (immutable index value->index)
;; Symbolic name (or #f)
(immutable symbol value->symbol)
;; Is this predefined (so eq? can be used),
;; or dynamically generated (so equal? must be used)?
(immutable dynamic? value-dynamic?)
;; Docstring (or #f)
(immutable docstring value-documentation)
;; thunked <enum>
(immutable part-of value-enum-thunk)
;; Source location (or #f)
(immutable source value-source))
(sealed #t)
(opaque #t))
(define (value=? x y)
"Compare two values of the same enumeration."
(assert (eq? ((value-enum-thunk x))
((value-enum-thunk y))))
(= (value->index x)
(value->index y)))
(define (value-enum enum)
"To which enumeration does @var{enum} belong?"
(let ((t (value-enum-thunk enum)))
(if t (t) #f)))
;; FIXME variant if enum is sparse
(define-record-type (<enum> %make-enum enum?)
(fields (immutable max enum-max-value)
(immutable symbol enum-name)
(immutable values enum-predefined-values)
(immutable source enum-source)
(immutable docstring enum-docstring))
(sealed #t)
(opaque #t))
;; Make sure record printing terminates.
;; Also include line numbers, and remove
;; uninteresting data (and data that takes
;; too much space).
(set-record-type-printer!
<value>
(lambda (record port)
(let ((sources (value-source record)))
(if sources
;; TODO source:[...] + syntax-source isn't correct,
;; at least on Guile 3.0.7, though no exception will result.
(format port "#<value (~a ~a) index: ~a at ~a:~a:~a>"
(enum-name ((value-enum-thunk record)))
(value->symbol record)
(value->index record)
(source:file sources)
(source:line sources)
(source:column sources))
(format port "#<value (~a ~a) index: ~a>"
(enum-name ((value-enum-thunk record)))
(value->symbol record)
(value->index record))))))
(set-record-type-printer!
<enum>
(lambda (record port)
(let ((sources (enum-source record)))
(if sources
(format port "#<enum ~a (max: ~a) at ~a:~a:~a>"
(enum-name record)
(enum-max-value record)
(source:file sources)
(source:line sources)
(source:column sources))
(format port "<enum ~a (max: ~a)>"
(enum-name record)
(enum-max-value record))))))
(define (%make-enum/fix max symbol values-proc source docstring)
(letrec ((e (%make-enum max symbol
(vector-map (lambda (vproc)
(vproc (lambda () e)))
values-proc)
source docstring)))
e))
(define (integer->value enum i)
(assert (and (exact? i) (integer? i)))
(assert (<= 0 i))
(assert (<= i (enum-max-value enum)))
(let ((predef (enum-predefined-values enum)))
(if (< i (vector-length predef))
(vector-ref predef i)
(%make-value i #f #t #f (lambda () enum) #f))))
;; Slow
(define (symbol->value enum s)
"Return the enum value in @var{enum} with symbol @var{s},
or #f it doesn't exist."
(let ((i (vector-index (compose (cute eq? s <>) value->symbol)
(enum-predefined-values enum))))
(and i (vector-ref (enum-predefined-values enum) i))))
;; Returned code is fast.
(define-syntax symbol-value
(lambda (x)
"Takes a (name of) a enumeration @var{enum} and literal symbol
@var{s} in that, and expands to an expression returning the enumeration
value. Due to technical reasons, @var{enum} must be a binding from a
module, and @var{enum} must be defined the same in the build and host."
(syntax-case x ()
((_ enum s)
(let-values (((type info) (syntax-local-binding #'enum)))
(case type
((global)
(let* ((module (resolve-module (cdr info)))
(enum@host (module-ref module (car info)))
(value@host (symbol->value enum@host
(syntax->datum #'s)))
(index (value->index value@host)))
#`(vector-ref (enum-predefined-values enum) #,index)))
(else (raise-exception
(syntax-violation 'symbol-value
"@var{enum} is not a global variable"
x
#'enum)))))))))
(define (syntax->list s)
(syntax-case s ()
(() '())
((x . rest)
(cons #'x (syntax->list #'rest)))))
(define-syntax value
(lambda (s)
(syntax-case s ()
((_ (x y) ...)
(let* ((key-value
(zip (map syntax->datum (syntax->list #'(x ...)))
(syntax->list #'(y ...))))
(index/syntax (assq-ref key-value 'index))
(index (car (syntax->datum index/syntax)))
(symbol/syntax (assq-ref key-value 'symbol))
(symbol (if symbol/syntax
(car (syntax->datum symbol/syntax))
#f))
(docstring/syntax
(assq-ref key-value 'documentation))
(docstring (if docstring/syntax
(car (syntax->datum docstring/syntax))
#f)))
(assert (and (exact? index) (integer? index)))
(when symbol
(assert (symbol? symbol)))
(when docstring
(assert (string? docstring)))
#`(lambda (thunk)
(%make-value #,index
'#,(datum->syntax s symbol)
#f
#,docstring
thunk
'#,(datum->syntax #f (syntax-source s)))))))))
;; TODO verify indices are correct
(define-syntax enumeration
(lambda (s)
(syntax-case s ()
((_ (name)
(#:documentation doc)
(#:max maximum)
(#:known entry ...))
#`(%make-enum/fix 'maximum
'name
(vector entry ...)
'#,(datum->syntax #f (syntax-source s))
doc)))))
(define-syntax define-enumeration
(syntax-rules ()
((_ (name enum-value?)
(#:documentation doc)
(#:max maximum)
(#:known entry ...))
(begin
(define name
(enumeration (name)
(#:documentation doc)
(#:max maximum)
(#:known entry ...)))
(define (enum-value? o)
(and (value? o)
(eq? name ((value-enum-thunk o)))))))))))
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