From: Stephen Adams Date: Fri, 9 Dec 1994 03:32:03 +0000 (+0000) Subject: Initial revision X-Git-Tag: 20090517-FFI~6887 X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=7718d507a4c2f23ea016050a82887d58cba425d4;p=mit-scheme.git Initial revision --- diff --git a/v7/src/runtime/macros.scm b/v7/src/runtime/macros.scm new file mode 100644 index 000000000..167967ce7 --- /dev/null +++ b/v7/src/runtime/macros.scm @@ -0,0 +1,368 @@ +#| -*-Scheme-*- + +$Id: macros.scm,v 1.1 1994/12/09 03:32:03 adams Exp $ + +Copyright (c) 1988-1993 Massachusetts Institute of Technology + +This material was developed by the Scheme project at the Massachusetts +Institute of Technology, Department of Electrical Engineering and +Computer Science. Permission to copy this software, to redistribute +it, and to use it for any purpose is granted, subject to the following +restrictions and understandings. + +1. Any copy made of this software must include this copyright notice +in full. + +2. Users of this software agree to make their best efforts (a) to +return to the MIT Scheme project any improvements or extensions that +they make, so that these may be included in future releases; and (b) +to inform MIT of noteworthy uses of this software. + +3. All materials developed as a consequence of the use of this +software shall duly acknowledge such use, in accordance with the usual +standards of acknowledging credit in academic research. + +4. MIT has made no warrantee or representation that the operation of +this software will be error-free, and MIT is under no obligation to +provide any services, by way of maintenance, update, or otherwise. + +5. In conjunction with products arising from the use of this material, +there shall be no use of the name of the Massachusetts Institute of +Technology nor of any adaptation thereof in any advertising, +promotional, or sales literature without prior written consent from +MIT in each case. |# + +;;;; More Special Forms +;;; package: (runtime macros) + +(declare (usual-integrations)) + +(define (initialize-package!) + (for-each (lambda (keyword transform) + (syntax-table-define system-global-syntax-table keyword + transform)) + '(AND + BKPT + CASE + CONS-STREAM + DEFINE-INTEGRABLE + DO + LET* + LETREC + MAKE-ENVIRONMENT + QUASIQUOTE + SEQUENCE) + (list transform/and + transform/bkpt + transform/case + transform/cons-stream + transform/define-integrable + transform/do + transform/let* + transform/letrec + transform/make-environment + transform/quasiquote + transform/sequence))) + +(define (make-absolute-reference name) + `(ACCESS ,name #F)) + +(define (transform/and . expressions) + (if (null? expressions) + '#T + (let loop ((expressions expressions)) + (if (null? (cdr expressions)) + (car expressions) + `(IF ,(car expressions) + ,(loop (cdr expressions)) + #F))))) + +(define (transform/cons-stream head tail) + `(,(make-absolute-reference 'CONS) ,head (DELAY ,tail))) + +(define (transform/make-environment . body) + `((NAMED-LAMBDA (,lambda-tag:make-environment) + ,@body + (THE-ENVIRONMENT)))) + +(define (transform/sequence . actions) + `(BEGIN . ,actions)) + +(define (transform/bkpt datum . arguments) + `(,(make-absolute-reference 'BREAKPOINT-PROCEDURE) (THE-ENVIRONMENT) + ,datum + ,@arguments)) + +;;;; Quasiquote + +(define (transform/quasiquote expression) + (descend-quasiquote expression 0 finalize-quasiquote)) + +(define (descend-quasiquote x level return) + (cond ((pair? x) (descend-quasiquote-pair x level return)) + ((vector? x) (descend-quasiquote-vector x level return)) + (else (return 'QUOTE x)))) + +(define (descend-quasiquote-pair x level return) + (define (descend-quasiquote-pair* level) + (descend-quasiquote (car x) level + (lambda (car-mode car-arg) + (descend-quasiquote (cdr x) level + (lambda (cdr-mode cdr-arg) + (cond ((and (eq? car-mode 'QUOTE) + (eq? cdr-mode 'QUOTE)) + (return 'QUOTE x)) + ((eq? car-mode 'UNQUOTE-SPLICING) + (if (and (eq? cdr-mode 'QUOTE) + (null? cdr-arg)) + (return 'UNQUOTE car-arg) + (return (make-absolute-reference 'APPEND) + (list car-arg + (finalize-quasiquote cdr-mode cdr-arg))))) + ((and (eq? cdr-mode 'QUOTE) + (null? cdr-arg)) + (return 'LIST + (list (finalize-quasiquote car-mode car-arg)))) + ((and (eq? cdr-mode 'QUOTE) + (list? cdr-arg)) + (return 'LIST + (cons (finalize-quasiquote car-mode car-arg) + (map (lambda (el) + (finalize-quasiquote 'QUOTE el)) + cdr-arg)))) + ((memq cdr-mode '(LIST CONS)) + (return cdr-mode + (cons (finalize-quasiquote car-mode car-arg) + cdr-arg))) + (else + (return + 'CONS + (list (finalize-quasiquote car-mode car-arg) + (finalize-quasiquote cdr-mode cdr-arg)))))))))) + (cond ((and (eq? (car x) 'QUASIQUOTE) + (pair? (cdr x)) + (null? (cddr x))) + (descend-quasiquote-pair* (1+ level))) + ((and (or (eq? (car x) 'UNQUOTE) + (eq? (car x) 'UNQUOTE-SPLICING)) + (pair? (cdr x)) + (null? (cddr x))) + (if (zero? level) + (return (car x) (cadr x)) + (descend-quasiquote-pair* (- level 1)))) + (else + (descend-quasiquote-pair* level)))) + +(define (descend-quasiquote-vector x level return) + (descend-quasiquote (vector->list x) level + (lambda (mode arg) + (case mode + ((QUOTE) + (return 'QUOTE x)) + ((LIST) + (return (make-absolute-reference 'VECTOR) arg)) + (else + (return (make-absolute-reference 'LIST->VECTOR) + (list (finalize-quasiquote mode arg)))))))) + +(define (finalize-quasiquote mode arg) + (case mode + ((QUOTE) `',arg) + ((UNQUOTE) arg) + ((UNQUOTE-SPLICING) (error ",@ in illegal context" arg)) + ((LIST) `(,(make-absolute-reference 'LIST) ,@arg)) + ((CONS) + (if (= (length arg) 2) + `(,(make-absolute-reference 'CONS) ,@arg) + `(,(make-absolute-reference 'CONS*) ,@arg))) + (else `(,mode ,@arg)))) + +(define (transform/case expr . clauses) + (let ((need-temp? (not (symbol? expr)))) + (let ((the-expression (if need-temp? (generate-uninterned-symbol) expr))) + (define (process-clauses clauses) + (if (null? clauses) + '() + (let ((selector (caar clauses)) + (rest (process-clauses (cdr clauses)))) + (if (null? selector) + rest + `((,(cond ((eq? selector 'ELSE) + (if (not (null? (cdr clauses))) + (error "CASE SYNTAX: ELSE not last clause" + clauses)) + 'ELSE) + ((pair? selector) + (transform selector)) + (else + (single-clause selector))) + ,@(cdar clauses)) + ,@rest))))) + + (define (check-selector selector) + (or (null? selector) + (and (eq-testable? (car selector)) + (check-selector (cdr selector))))) + + (define (eq-testable? selector) + (or (symbol? selector) + (char? selector) ;**** implementation dependent. + (fix:fixnum? selector) ;**** implementation dependent. + (eq? selector false) + (eq? selector true))) + + (define (single-clause selector) + `(,(if (eq-testable? selector) 'EQ? 'EQV?) ,the-expression ',selector)) + + (define (transform selector) + ;; Optimized for speed in compiled code. + (cond ((null? (cdr selector)) + (single-clause (car selector))) + ((null? (cddr selector)) + `(OR ,(single-clause (car selector)) + ,(single-clause (cadr selector)))) + ((null? (cdddr selector)) + `(OR ,(single-clause (car selector)) + ,(single-clause (cadr selector)) + ,(single-clause (caddr selector)))) + ((null? (cddddr selector)) + `(OR ,(single-clause (car selector)) + ,(single-clause (cadr selector)) + ,(single-clause (caddr selector)) + ,(single-clause (cadddr selector)))) + (else + `(,(if (check-selector selector) 'MEMQ 'MEMV) + ,the-expression ',selector)))) + + (let ((body `(COND ,@(process-clauses clauses)))) + (if need-temp? + `(let ((,the-expression ,expr)) + ,body) + body))))) + +(define (transform/let* bindings . body) + (guarantee-let-bindings bindings 'LET* #f) + (define (do-one bindings) + (if (null? bindings) + `(BEGIN ,@body) + `(LET (,(car bindings)) + ,(do-one (cdr bindings))))) + (if (null? bindings) + `(LET () ,@body) ; To allow internal definitions + (do-one bindings))) + +(define (transform/letrec bindings . body) + (guarantee-let-bindings bindings 'LETREC #f) + `(LET () + ,@(map (lambda (binding) `(DEFINE ,@binding)) bindings) + (LET () ; Internal definitions must be in + ; nested contour. + ,@body))) + +(define (transform/do bindings test . body) + (guarantee-let-bindings bindings 'DO #t) + (let ((the-name (string->uninterned-symbol "do-loop"))) + `(LET ,the-name + ,(map (lambda (binding) + (if (or (null? (cdr binding)) + (null? (cddr binding))) + binding + `(,(car binding) ,(cadr binding)))) + bindings) + ,(process-cond-clause test false + `(BEGIN + ,@body + (,the-name ,@(map (lambda (binding) + (if (or (null? (cdr binding)) + (null? (cddr binding))) + (car binding) + (caddr binding))) + bindings))))))) + +(define (guarantee-let-bindings bindings keyword do-like?) + (if (not (and (list? bindings) + (for-all? bindings + (lambda (binding) + (and (list? binding) + (not (null? binding)) + (symbol? (car binding)) + (or (null? (cdr binding)) + (null? (cddr binding)) + (and do-like? (null? (cdddr binding))))))))) + (error "SYNTAX: Bad bindings:" keyword bindings))) + +(define (process-cond-clause clause else-permitted? rest) + (if (or (null? clause) (not (list? clause))) + (error "cond-clause syntax: not a non-empty list:" clause)) + (cond ((eq? 'ELSE (car clause)) + (if (not else-permitted?) + (error "cond-clause syntax: ELSE not permitted:" clause)) + (if (null? (cdr clause)) + (error "cond-clause syntax: ELSE missing expressions:" clause)) + `(BEGIN ,@(cdr clause))) + ((null? (cdr clause)) + `(OR ,(car clause) ,rest)) + ((eq? '=> (cadr clause)) + (if (null? (cddr clause)) + (error "cond-clause syntax: => missing recipient:" clause)) + (if (not (null? (cdddr clause))) + (error "cond-clause syntax: misformed => clause:" clause)) + (let ((predicate (string->uninterned-symbol "predicate"))) + `(LET ((,predicate ,(car clause))) + (IF ,predicate + (,(caddr clause) ,predicate) + ,rest)))) + (else + (if (null? (cdr clause)) + (error "cond-clause syntax: missing expressions:" clause)) + `(IF ,(car clause) + (BEGIN ,@(cdr clause)) + ,rest)))) + +(define transform/define-integrable + (macro (pattern . body) + (parse-define-syntax pattern body + (lambda (name body) + `(BEGIN (DECLARE (INTEGRATE ,pattern)) + (DEFINE ,name ,@body))) + (lambda (pattern body) + `(BEGIN (DECLARE (INTEGRATE-OPERATOR ,(car pattern))) + (DEFINE ,pattern + ,@(if (list? (cdr pattern)) + `((DECLARE + (INTEGRATE + ,@(lambda-list->bound-names (cdr pattern))))) + '()) + ,@body)))))) + +(define (parse-define-syntax pattern body if-variable if-lambda) + (cond ((pair? pattern) + (let loop ((pattern pattern) (body body)) + (cond ((pair? (car pattern)) + (loop (car pattern) `((LAMBDA ,(cdr pattern) ,@body)))) + ((symbol? (car pattern)) + (if-lambda pattern body)) + (else + (error "Illegal name" (car pattern)))))) + ((symbol? pattern) + (if-variable pattern body)) + (else + (error "Illegal name" pattern)))) + +(define (lambda-list->bound-names lambda-list) + (cond ((null? lambda-list) + '()) + ((pair? lambda-list) + (let ((lambda-list + (if (eq? (car lambda-list) lambda-optional-tag) + (begin (if (not (pair? (cdr lambda-list))) + (error "Missing optional variable" lambda-list)) + (cdr lambda-list)) + lambda-list))) + (cons (let ((parameter (car lambda-list))) + (if (pair? parameter) (car parameter) parameter)) + (lambda-list->bound-names (cdr lambda-list))))) + (else + (if (not (symbol? lambda-list)) + (error "Illegal rest variable" lambda-list)) + (list lambda-list)))) \ No newline at end of file