From 7422aa099914e5d8c74f28580e961aec84d9de12 Mon Sep 17 00:00:00 2001 From: Chris Hanson Date: Fri, 9 Jan 2004 21:12:19 +0000 Subject: [PATCH] Implement REVERSE* and REVERSE*!, like REVERSE and REVERSE! but a non-null tail element can be specified. --- v7/src/runtime/list.scm | 25 +++++++++++-------------- v7/src/runtime/runtime.pkg | 4 +++- 2 files changed, 14 insertions(+), 15 deletions(-) diff --git a/v7/src/runtime/list.scm b/v7/src/runtime/list.scm index 2be56e537..dddb93d0a 100644 --- a/v7/src/runtime/list.scm +++ b/v7/src/runtime/list.scm @@ -1,10 +1,10 @@ #| -*-Scheme-*- -$Id: list.scm,v 14.37 2003/04/25 03:31:49 cph Exp $ +$Id: list.scm,v 14.38 2004/01/09 21:12:16 cph Exp $ Copyright 1986,1987,1988,1989,1990,1991 Massachusetts Institute of Technology Copyright 1992,1993,1994,1995,1996,2000 Massachusetts Institute of Technology -Copyright 2001,2002,2003 Massachusetts Institute of Technology +Copyright 2001,2002,2003,2004 Massachusetts Institute of Technology This file is part of MIT/GNU Scheme. @@ -434,8 +434,8 @@ USA. ;;; clever compiler could optimize this into the obvious loop that ;;; everyone would write in assembly language. -(define (append . lists) - (%append lists)) +(define (append . lists) (%append lists)) +(define (append! . lists) (%append! lists)) (define (%append lists) (let ((lists (reverse! lists))) @@ -466,9 +466,6 @@ USA. accum)) '()))) -(define (append! . lists) - (%append! lists)) - (define (%append! lists) (if (pair? lists) (let loop ((head (car lists)) (tail (cdr lists))) @@ -483,27 +480,27 @@ USA. (loop (car tail) (cdr tail))))) '())) -(define (reverse l) - (%reverse l '())) +(define (reverse l) (reverse* l '())) +(define (reverse! l) (reverse*! l '())) -(define (%reverse l tail) +(define (reverse* l tail) (let loop ((rest l) (so-far tail)) (if (pair? rest) (loop (cdr rest) (cons (car rest) so-far)) (begin (if (not (null? rest)) - (error:wrong-type-argument l "list" '%REVERSE)) + (error:wrong-type-argument l "list" 'REVERSE*)) so-far)))) -(define (reverse! l) - (let loop ((current l) (new-cdr '())) +(define (reverse*! l tail) + (let loop ((current l) (new-cdr tail)) (if (pair? current) (let ((next (cdr current))) (set-cdr! current new-cdr) (loop next current)) (begin (if (not (null? current)) - (error:wrong-type-argument l "list" 'REVERSE!)) + (error:wrong-type-argument l "list" 'REVERSE*!)) new-cdr)))) ;;;; Mapping Procedures diff --git a/v7/src/runtime/runtime.pkg b/v7/src/runtime/runtime.pkg index f1f84a189..560f71878 100644 --- a/v7/src/runtime/runtime.pkg +++ b/v7/src/runtime/runtime.pkg @@ -1,6 +1,6 @@ #| -*-Scheme-*- -$Id: runtime.pkg,v 14.470 2004/01/06 06:22:37 cph Exp $ +$Id: runtime.pkg,v 14.471 2004/01/09 21:12:19 cph Exp $ Copyright 1988,1989,1990,1991,1992,1993 Massachusetts Institute of Technology Copyright 1994,1995,1996,1997,1998,1999 Massachusetts Institute of Technology @@ -2104,6 +2104,8 @@ USA. reduce-right reverse reverse! + reverse* + reverse*! second set-car! set-cdr! -- 2.25.1