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| ;;; Multi-language support | |
| ;; Copyright (C) 2001, 2009, 2010, 2011, 2013 Free Software Foundation, Inc. | |
| ;; This library is free software; you can redistribute it and/or | |
| ;; modify it under the terms of the GNU Lesser General Public | |
| ;; License as published by the Free Software Foundation; either | |
| ;; version 3 of the License, or (at your option) any later version. | |
| ;; | |
| ;; This library 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 | |
| ;; Lesser General Public License for more details. | |
| ;; | |
| ;; You should have received a copy of the GNU Lesser General Public | |
| ;; License along with this library; if not, write to the Free Software | |
| ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
| ;; 02110-1301 USA | |
| ;;; Code: | |
| (define-module (system base language) | |
| #:use-module (system base syntax) | |
| #:export (define-language language? lookup-language make-language | |
| language-name language-title language-reader | |
| language-printer language-parser | |
| language-compilers language-decompilers language-evaluator | |
| language-joiner language-for-humans? | |
| language-make-default-environment | |
| lookup-compilation-order lookup-decompilation-order | |
| invalidate-compilation-cache! default-environment | |
| *current-language*) | |
| #:re-export (current-language)) | |
| ;;; | |
| ;;; Language class | |
| ;;; | |
| (define-record/keywords <language> | |
| name | |
| title | |
| reader | |
| printer | |
| (parser #f) | |
| (compilers '()) | |
| (decompilers '()) | |
| (evaluator #f) | |
| (joiner #f) | |
| (for-humans? #t) | |
| (make-default-environment make-fresh-user-module)) | |
| (define-macro (define-language name . spec) | |
| `(begin | |
| (invalidate-compilation-cache!) | |
| (define ,name (make-language #:name ',name ,@spec)))) | |
| (define (lookup-language name) | |
| (let ((m (resolve-module `(language ,name spec)))) | |
| (if (module-bound? m name) | |
| (module-ref m name) | |
| (error "no such language" name)))) | |
| (define *compilation-cache* '()) | |
| (define *decompilation-cache* '()) | |
| (define (invalidate-compilation-cache!) | |
| (set! *decompilation-cache* '()) | |
| (set! *compilation-cache* '())) | |
| (define (compute-translation-order from to language-translators) | |
| (cond | |
| ((not (language? to)) | |
| (compute-translation-order from (lookup-language to) language-translators)) | |
| (else | |
| (let lp ((from from) (seen '())) | |
| (cond | |
| ((not (language? from)) | |
| (lp (lookup-language from) seen)) | |
| ((eq? from to) (reverse! seen)) | |
| ((memq from seen) #f) | |
| (else (or-map (lambda (pair) | |
| (lp (car pair) (acons from (cdr pair) seen))) | |
| (language-translators from)))))))) | |
| (define (lookup-compilation-order from to) | |
| (let ((key (cons from to))) | |
| (or (assoc-ref *compilation-cache* key) | |
| (let ((order (compute-translation-order from to language-compilers))) | |
| (set! *compilation-cache* | |
| (acons key order *compilation-cache*)) | |
| order)))) | |
| (define (lookup-decompilation-order from to) | |
| (let ((key (cons from to))) | |
| (or (assoc-ref *decompilation-cache* key) | |
| ;; trickery! | |
| (let ((order (and=> | |
| (compute-translation-order to from language-decompilers) | |
| reverse!))) | |
| (set! *decompilation-cache* (acons key order *decompilation-cache*)) | |
| order)))) | |
| (define (default-environment lang) | |
| "Return the default compilation environment for source language LANG." | |
| ((language-make-default-environment | |
| (if (language? lang) lang (lookup-language lang))))) | |
| ;;; | |
| ;;; Current language | |
| ;;; | |
| ;; Deprecated; use current-language instead. | |
| (define *current-language* (parameter-fluid current-language)) | |