計算機プログラムの構造と解釈[第2版]
(翔泳社)
ハロルド エイブルソン (著)ジュリー サスマン (著)
ジェラルド・ジェイ サスマン (著)
Harold Abelson (原著)Julie Sussman (原著)
Gerald Jay Sussman (原著)和田 英一 (翻訳)
開発環境
- OS X Yosemite - Apple (OS)
- Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
- Scheme (プログラミング言語)
- Gauche (処理系)
計算機プログラムの構造と解釈[第2版](ハロルド エイブルソン (著)、ジュリー サスマン (著)、ジェラルド・ジェイ サスマン (著)、Harold Abelson (原著)、Julie Sussman (原著)、Gerald Jay Sussman (原著)、和田 英一 (翻訳)、翔泳社、原書: Structure and Interpretation of Computer Programs (MIT Electrical Engineering and Computer Science)(SICP))の5(レジスタ計算機での計算)、5.3(記憶の割り当てとごみ集め)、5.3.1(ベクターとしてのメモリー)、Lispデータの表現、基本リスト演算の実装、スタックの実装、問題 5.22-1.を解いてみる。
その他参考書籍
- Instructor's Manual to Accompany Structure & Interpretation of Computer Programs
- プログラミングGauche (Kahuaプロジェクト (著), 川合 史朗 (監修), オライリージャパン)
- Scheme手習い
問題 5.22-1.
コード(BBEdit, Emacs)
sample22_1.scm
#!/usr/bin/env gosh
;;-*- coding: utf-8 -*-
(load "./simulator.scm")
(define append-machine
(make-machine
(list (list 'null? null?)
(list 'car car)
(list 'cdr cdr)
(list 'cons cons))
'((assign continue (label append-done))
test
(test (op null?) (reg x))
(branch (label null))
(save continue)
(assign continue (label cons))
(assign t (op car) (reg x))
(save t)
(assign x (op cdr) (reg x))
(goto (label test))
cons
(restore t)
(assign val (op cons) (reg t) (reg val))
(restore continue)
(goto (reg continue))
null
(assign val (reg y))
(goto (reg continue))
append-done)))
(print "(append '() '())")
(set-register-contents! append-machine 'x '())
(set-register-contents! append-machine 'y '())
(start append-machine)
(print (get-register-contents append-machine 'val))
(print "(append '(1) '())")
(set-register-contents! append-machine 'x '(1))
(set-register-contents! append-machine 'y '())
(start append-machine)
(print (get-register-contents append-machine 'val))
(print "(append '() '(2))")
(set-register-contents! append-machine 'x '())
(set-register-contents! append-machine 'y '(2))
(start append-machine)
(print (get-register-contents append-machine 'val))
(print "(append '(1 2) '(3 4 5))")
(set-register-contents! append-machine 'x '(1 2))
(set-register-contents! append-machine 'y '(3 4 5))
(start append-machine)
(print (get-register-contents append-machine 'val))
(print "(append '((1 2) () (3 (4 5) 6) 7 ()) '((9) 10))")
(set-register-contents! append-machine 'x '((1 2) () (3 (4 5) 6) 7 ()))
(set-register-contents! append-machine 'y '((9) 10))
(start append-machine)
(print (get-register-contents append-machine 'val))
simulator.scm
;; -*- coding: utf-8 -*-
(define (tagged-list? exp tag)
(if (pair? exp)
(eq? (car exp) tag)
#f))
(define (make-machine ops controller-text)
(let ((machine (make-new-machine)))
((machine 'install-operations) ops)
((machine 'install-instruction-sequence)
(assemble controller-text machine))
machine))
(define (make-register name)
(let ((contents '*unassigned*)
(trace #f))
(define (dispatch message)
(cond ((eq? message 'get) contents)
((eq? message 'set)
(lambda (value) (set! contents value)))
((eq? message 'trace-on)
(set! trace #t))
((eq? message 'trace-off)
(set! trace #f))
((eq? message 'trace?) trace)
(else
(error "Unknown request -- REGISTER" message))))
dispatch))
(define (get-contents register)
(register 'get))
(define (set-contents! register value)
((register 'set) value))
(define (make-stack)
(let ((s '())
(number-pushes 0)
(max-depth 0)
(current-depth 0))
(define (push x)
(set! s (cons x s))
(set! number-pushes (+ 1 number-pushes))
(set! current-depth (+ 1 current-depth))
(set! max-depth (max current-depth max-depth)))
(define (pop)
(if (null? s)
(error "Empty stack -- POP")
(let ((top (car s)))
(set! s (cdr s))
(set! current-depth (- current-depth 1))
top)))
(define (initialize)
(set! s '())
(set! number-pushes 0)
(set! max-depth 0)
(set! current-depth 0))
(define (print-statistics)
(print (list 'total-pushes '= number-pushes
'maximum-depth '= max-depth)))
(define (dispatch message)
(cond ((eq? message 'push) push)
((eq? message 'pop) (pop))
((eq? message 'initialize) (initialize))
((eq? message 'print-statistics)
(print-statistics))
(else (error "Unknown request -- STACK"
message))))
dispatch))
(define (pop stack)
(stack 'pop))
(define (push stack value)
((stack 'push) value))
(define (print-statistics machine)
((machine 'stack) 'print-statistics))
(define (make-new-machine)
(let ((pc (make-register 'pc))
(flag (make-register 'flag))
(stack (make-stack))
(the-instruction-sequence '())
(instruction-counting 0)
(trace-flag #f)
(label '())
(breakpoints '())
(current-n -1))
(let ((the-ops
(list (list 'initialize-stack
(lambda () (stack 'initialize)))
(list 'print-stack-statisstics
(lambda () (stack 'print-statistics)))))
(register-table
(list (list 'pc pc) (list 'flag flag))))
(define (allocate-register name)
(if (assoc name register-table)
(error "Multiply defined register: " name)
(set! register-table
(cons (list name (make-register name))
register-table)))
'register-allocated)
(define (lookup-register name)
(let ((val (assoc name register-table)))
(if val
(cadr val)
(begin (allocate-register name)
(lookup-register name)))))
(define (execute)
(let ((insts (get-contents pc)))
(if (null? insts)
'done
(begin
(if (eq? (caaar insts) 'label)
(begin (set! label (cadr (caar insts)))
(set! current-n 0))
(set! instruction-counting (+ instruction-counting 1)))
(if trace-flag
(print "label: " label ", trace: " (caar insts)))
(let ((val (assoc label breakpoints)))
(if (and val
(memq current-n (cdr val)))
(print "break label:" label " offset:" current-n)
(begin ((instruction-execution-proc (car insts)))
(set! current-n (+ current-n 1))
(execute))))))))
(define (set-breakpoint label n)
(let ((val (assoc label breakpoints)))
(if val
(set-cdr! val (cons n (cdr val)))
(set! breakpoints (cons (cons label (list n)) breakpoints))))
'done)
(define (proceed-machine)
(let ((insts (get-contents pc)))
(if (null? insts)
'done
(begin
(if (eq? (caaar insts) 'label)
(begin (set! label (cadr (caar insts)))
(set! current-n 0))
(set! instruction-counting (+ instruction-counting 1)))
(if trace-flag
(print "label: " label ", trace: " (caar insts)))
(begin ((instruction-execution-proc (car insts)))
(set! current-n (+ current-n 1))
(execute))))))
(define (cancel-breakpoint label n)
(let ((val (assoc label breakpoints)))
(if val
(set-cdr! val (filter (lambda (i)
(not (= i n)))
(cdr val))))))
(define (dispatch message)
(cond ((eq? message 'start)
(set-contents! pc the-instruction-sequence)
(execute))
((eq? message 'install-instruction-sequence)
(lambda (seq) (set! the-instruction-sequence seq)))
((eq? message 'allocate-register) allocate-register)
((eq? message 'get-register) lookup-register)
((eq? message 'install-operations)
(lambda (ops) (set! the-ops (append the-ops ops))))
((eq? message 'stack) stack)
((eq? message 'operations) the-ops)
((eq? message 'print-instruction-counting)
(print "(instruction-counting = " instruction-counting ")"))
((eq? message 'initialize-instruction-counting)
(set! instruction-counting 0)
'done)
((eq? message 'trace-on) (set! trace-flag #t))
((eq? message 'trace-off) (set! trace-flag #f))
((eq? message 'trace-register-on)
(lambda (reg-name)
(let ((val (lookup-register reg-name)))
(if val
(val 'trace-on)
(error "Unknown register:" reg-name)))))
((eq? message 'trace-register-off)
(lambda (reg-name)
(let ((val (lookup-register reg-name)))
(if val
(val 'trace-off)
(error "Unknown register:" reg-name)))))
((eq? message 'set-breakpoint) set-breakpoint)
((eq? message 'proceed-machine) proceed-machine)
((eq? message 'cancel-breakpoint) cancel-breakpoint)
((eq? message 'cancel-all-breakpoints)
(set! breakpoints '()))
(else (error "Unknown request -- MACHINE" message))))
dispatch)))
(define (start machine)
(machine 'start))
(define (get-register-contents machine register-name)
(get-contents (get-register machine register-name)))
(define (set-register-contents! machine register-name value)
(set-contents! (get-register machine register-name) value)
'done)
(define (get-register machine reg-name)
((machine 'get-register) reg-name))
(define (print-instruction-counting machine)
(machine 'print-instruction-counting))
(define (initialize-instruction-counting machine)
(machine 'initialize-instruction-counting))
(define (trace-register-on machine register-name)
((machine 'trace-register-on) register-name))
(define (trace-register-off machine register-name)
((machine 'trace-register-off) register-name))
(define (trace-on machine)
(machine 'trace-on))
(define (trace-off machine)
(machine 'trace-off))
(define (set-breakpoint machine label n)
((machine 'set-breakpoint) label n))
(define (proceed-machine machine)
((machine 'proceed-machine)))
(define (cancel-breakpoint machine label n)
((machine 'cancel-breakpoint) label n))
(define (cancel-all-breakpoints machine)
(machine 'cancel-all-breakpoints))
(define (assemble controller-text machine)
(extract-labels controller-text
(lambda (insts labels)
(update-insts! insts labels machine)
insts)))
(define (extract-labels text receive)
(if (null? text)
(receive '() '())
(extract-labels
(cdr text)
(lambda (insts labels)
(let ((next-inst (car text)))
(if (symbol? next-inst)
(if (assoc next-inst labels)
(error "Multiply defined label:" next-inst)
(begin (set! insts (cons (list (list 'label next-inst))
insts))
(receive insts
(cons (make-label-entry next-inst
insts)
labels))))
(receive (cons (make-instruction next-inst)
insts)
labels)))))))
(define (update-insts! insts labels machine)
(let ((pc (get-register machine 'pc))
(flag (get-register machine 'flag))
(stack (machine 'stack))
(ops (machine 'operations)))
(for-each
(lambda (inst)
(set-instruction-execution-proc!
inst
(make-execution-procedure
(instruction-text inst) labels machine
pc flag stack ops)))
insts)))
(define (make-instruction text)
(cons text '()))
(define (instruction-text inst)
(car inst))
(define (instruction-execution-proc inst)
(cdr inst))
(define (set-instruction-execution-proc! inst proc)
(set-cdr! inst proc))
(define (make-label-entry label-name insts)
(cons label-name insts))
(define (lookup-label labels label-name)
(let ((val (assoc label-name labels)))
(if val
(cdr val)
(error "Undefined label -- ASSEMBLE" label-name))))
(define (make-execution-procedure inst labels machine pc flag stack ops)
(cond ((eq? (car inst) 'assign)
(make-assign inst machine labels ops pc))
((eq? (car inst) 'test)
(make-test inst machine labels ops flag pc))
((eq? (car inst) 'branch)
(make-branch inst machine labels flag pc))
((eq? (car inst) 'goto)
(make-goto inst machine labels pc))
((eq? (car inst) 'save)
(make-save inst machine stack pc))
((eq? (car inst) 'restore)
(make-restore inst machine stack pc))
((eq? (car inst) 'perform)
(make-perform inst machine labels ops pc))
((eq? (car inst) 'del)
((make-del inst machine pc)))
((eq? (car inst) 'label)
(lambda () (advance-pc pc)))
(else (error "Unknown instruction type -- ASSEMBLE"
inst))))
(define (make-assign inst machine labels operations pc)
(let ((target
(get-register machine (assign-reg-name inst)))
(value-exp (assign-value-exp inst)))
(let ((value-proc
(if (operation-exp? value-exp)
(make-operation-exp
value-exp machine labels operations)
(make-primitive-exp
(car value-exp) machine labels))))
(lambda ()
(if (target 'trace?)
(print "register-name:" (assign-reg-name inst)
" old:" (get-contents target)
" new:" (value-proc)))
(set-contents! target (value-proc))
(advance-pc pc)))))
(define (assign-reg-name assign-instruction)
(cadr assign-instruction))
(define (assign-value-exp assign-instruction)
(cddr assign-instruction))
(define (advance-pc pc)
(set-contents! pc (cdr (get-contents pc))))
(define (make-test inst machine labels operations flag pc)
(let ((condition (test-condition inst)))
(if (operation-exp? condition)
(let ((condition-proc
(make-operation-exp
condition machine labels operations)))
(lambda ()
(set-contents! flag (condition-proc))
(advance-pc pc)))
(error "Bad TEST instruction -- ASSEMBLE" inst))))
(define (test-condition test-instruction)
(cdr test-instruction))
(define (make-branch inst machine labels flag pc)
(let ((dest (branch-dest inst)))
(if (label-exp? dest)
(let ((insts
(lookup-label labels (label-exp-label dest))))
(lambda ()
(if (get-contents flag)
(set-contents! pc insts)
(advance-pc pc))))
(error "Bad BRANCH instruction -- ASSEMBLE" inst))))
(define (branch-dest branch-instruction)
(cadr branch-instruction))
(define (make-goto inst machine labels pc)
(let ((dest (goto-dest inst)))
(cond ((label-exp? dest)
(let ((insts
(lookup-label labels
(label-exp-label dest))))
(lambda () (set-contents! pc insts))))
((register-exp? dest)
(let ((reg
(get-register machine
(register-exp-reg dest))))
(lambda ()
(set-contents! pc (get-contents reg)))))
(else (error "Bad GOTO instruction -- ASSEMBLE"
inst)))))
(define (goto-dest goto-instruction)
(cadr goto-instruction))
(define (make-save inst machine stack pc)
(let ((reg (get-register machine
(stack-inst-reg-name inst))))
(lambda ()
(push stack (get-contents reg))
(advance-pc pc))))
(define (make-restore inst machine stack pc)
(let ((reg (get-register machine
(stack-inst-reg-name inst))))
(lambda ()
(set-contents! reg (pop stack))
(advance-pc pc))))
(define (stack-inst-reg-name stack-instruction)
(cadr stack-instruction))
(define (make-perform inst machine labels operations pc)
(let ((action (perform-action inst)))
(if (operation-exp? action)
(let ((action-proc
(make-operation-exp
action machine labels operations)))
(lambda ()
(action-proc)
(advance-pc pc)))
(error "Bad PERFORM instruction -- ASSEMBLE" inst))))
(define (perform-action inst) (cdr inst))
(define (make-primitive-exp exp machine labels)
(cond ((constant-exp? exp)
(let ((c (constant-exp-value exp)))
(lambda () c)))
((label-exp? exp)
(let ((insts
(lookup-label labels
(label-exp-label exp))))
(lambda () insts)))
((register-exp? exp)
(let ((r (get-register machine
(register-exp-reg exp))))
(lambda () (get-contents r))))
(else
(error "Unknown expression type -- ASSEMBLE" exp))))
(define (register-exp? exp) (tagged-list? exp 'reg))
(define (register-exp-reg exp) (cadr exp))
(define (constant-exp? exp) (tagged-list? exp 'const))
(define (constant-exp-value exp) (cadr exp))
(define (label-exp? exp) (tagged-list? exp 'label))
(define (label-exp-label exp) (cadr exp))
(define (make-operation-exp exp machine labels operations)
(let ((op (lookup-prim (operation-exp-op exp) operations))
(aprocs
(map (lambda (e)
(if (label-exp? e)
(error "Bad OPERANDS instruction -- ASSEMBLE" e)
(make-primitive-exp e machine labels)))
(operation-exp-operands exp))))
(lambda ()
(apply op (map (lambda (p) (p)) aprocs)))))
(define (operation-exp? exp)
(and (pair? exp) (tagged-list? (car exp) 'op)))
(define (operation-exp-op operation-exp)
(cadr (car operation-exp)))
(define (operation-exp-operands operation-exp)
(cdr operation-exp))
(define (lookup-prim symbol operations)
(let ((val (assoc symbol operations)))
(if val
(cadr val)
(error "Unknown operation -- ASSEMBLE" symbol))))
(define (make-del inst machine pc)
(let ((target
(get-register machine (del-reg-name inst))))
(lambda ()
(set-contents! target '*unassigned*)
(advance-pc pc))))
(define (del-reg-name delete-instruction)
(cadr delete-instruction))
入出力結果(Terminal(gosh), REPL(Read, Eval, Print, Loop))
$ ./sample22_1.scm (append '() '()) () (append '(1) '()) (1) (append '() '(2)) (2) (append '(1 2) '(3 4 5)) (1 2 3 4 5) (append '((1 2) () (3 (4 5) 6) 7 ()) '((9) 10)) ((1 2) () (3 (4 5) 6) 7 () (9) 10) $
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