2015年1月7日水曜日

開発環境

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)、5.5(翻訳系)、5.5.6(文面アドレス)、問題 5.40.を解いてみる。

その他参考書籍

問題 5.40.

コード(BBEdit, Emacs)

compiler40.scm

;; -*- coding;: utf-8 -*-

(load "./operations.scm")

(define (compile exp target linkage compile-time-env)
  (cond ((self-evaluating? exp)
         (compile-self-evaluating exp target linkage))
        ((quoted? exp) (compile-quoted exp target linkage))
        ((variable? exp)
         (compile-variable exp target linkage))
        ((assignment? exp)
         (compile-assignment exp target linkage compile-time-env))
        ((definition? exp)
         (compile-definition exp target linkage compile-time-env))
        ((if? exp) (compile-if exp target linkage compile-time-env))
        ((lambda? exp) (compile-lambda exp target linkage compile-time-env))
        ((begin? exp)
         (compile-sequence (begin-actions exp)
                           target
                           linkage
                           compile-time-env))
        ((cond? exp) (compile (cond->if exp) target linkage compile-time-env))
        ((application? exp)
         (compile-application exp target linkage compile-time-env))
        (else
         (error "Unknown expression type -- COMPILE" exp))))

(define (make-instruction-sequence needs modifies statements)
  (list needs modifies statements))

(define (empty-instruction-sequence)
  (make-instruction-sequence '() '() '()))

(define (compile-linkage linkage)
  (cond ((eq? linkage 'return)
         (make-instruction-sequence '(continue) '()
                                    '((goto (reg continue)))))
        ((eq? linkage 'next)
         (empty-instruction-sequence))
        (else
         (make-instruction-sequence '() '()
                                    `((goto (label ,linkage)))))))

(define (end-with-linkage linkage instruction-sequence)
  (preserving '(continue)
              instruction-sequence
              (compile-linkage linkage)))

(define (compile-self-evaluating exp target linkage)
  (end-with-linkage linkage
                    (make-instruction-sequence
                     '()
                     (list target)
                     `((assign ,target (const ,exp))))))

(define (compile-quoted exp target linkage)
  (end-with-linkage linkage
                    (make-instruction-sequence
                     '()
                     (list target)
                     `((assign ,target (const ,(text-of-quotation exp)))))))

(define (compile-variable exp target linkage)
  (end-with-linkage linkage
                    (make-instruction-sequence
                     '(env)
                     (list target)
                     `((assign ,target
                               (op lookup-variable-value)
                               (const ,exp)
                               (reg env))))))

(define (compile-assignment exp target list compile-time-env)
  (let ((var (assignment-variable exp))
        (get-value-code
         (compile (assignment-value exp) 'val 'next compile-time-env)))
    (end-with-linkage
     linkage
     (preserving '(env)
                 get-value-code
                 (make-instruction-sequence
                  '(env val)
                  (list target)
                  `((perform (op set-variable-value!)
                             (const ,var)
                             (reg val)
                             (reg env))
                    (assign ,target (const ok))))))))

(define (compile-definition exp target linkage compile-time-env)
  (let ((var (definition-variable exp))
        (get-value-code
         (compile (definition-value exp) 'val 'next compile-time-env)))
    (end-with-linkage
     linkage
     (preserving '(env)
                 get-value-code
                 (make-instruction-sequence
                  '(env val)
                  (list target)
                  `((perform (op define-variable!)
                             (const ,var)
                             (reg val)
                             (reg env))
                    (assign ,target (const ok))))))))

(define (compile-if exp target linkage compile-time-env)
  (let ((t-branch (make-label 'true-branch))
        (f-branch (make-label 'false-branch))
        (after-if (make-label 'after-if)))
    (let ((consequent-linkage
           (if (eq? linkage 'next) after-if linkage)))
      (let ((p-code (compile (if-predicate exp) 'val 'next compile-time-env))
            (c-code
             (compile
              (if-consequent exp) target consequent-linkage))
            (a-code
             (compile (if-alternative exp) target linkage compile-time-env)))
        (preserving
         '(env continue)
         p-code
         (append-instruction-sequences
          (make-instruction-sequence
           '(val)
           '()
           `((test (op false?) (reg val))
             (branch (label ,f-branch))))
          (parallel-instruction-sequences
           (append-instruction-sequences t-branch c-code)
           (append-instruction-sequences f-branch a-code))
          after-if))))))

(define (compile-sequence seq target linkage compile-time-env)
  (if (last-exp? seq)
      (compile (first-exp seq) target linkage compile-time-env)
      (preserving '(env continue)
                  (compile (first-exp seq) target 'next compile-time-env)
                  (compile-sequence (rest-exps seq)
                                    target
                                    linkage
                                    compile-time-env))))

(define (compile-lambda exp target linkage compile-time-env)
  (let ((proc-entry (make-label 'entry))
        (after-lambda (make-label 'after-lambda)))
    (let ((lambda-linkage
           (if (eq? linkage 'next) after-lambda linkage)))
      (append-instruction-sequences
       (tack-on-instruction-sequence
        (end-with-linkage
         lambda-linkage
         (make-instruction-sequence
          '(env)
          (list target)
          `((assign ,target
                    (op make-compiled-procedure)
                    (label ,proc-entry)
                    (reg env)))))
        (compile-lambda-body exp proc-entry compile-time-env))
       after-lambda))))

(define (compile-lambda-body exp proc-entry compile-time-env)
  (let ((formals (lambda-parameters exp)))
    (append-instruction-sequences
     (make-instruction-sequence
      '(env proc argl)
      '(env)
      `(,proc-entry
        (assign env (op compiled-procedure-env) (reg proc))
        (assign env
                (op extend-environment)
                (const ,formals)
                (reg argl)
                (reg env))))
     (compile-sequence (lambda-body exp)
                       'val
                       'return
                       (extend-compile-time-env formals
                                                compile-time-env)))))

(define (compile-application exp target linkage compile-time-env)
  (let ((proc-code (compile (operator exp) 'proc 'next compile-time-env))
        (operand-codes
         (map (lambda (operand) (compile operand 'val 'next compile-time-env))
              (operands exp))))
    (preserving '(env continue)
                proc-code
                (preserving '(proc continue)
                            (construct-arglist operand-codes)
                            (compile-procedure-call target
                                                    linkage
                                                    compile-time-env)))))

(define (construct-arglist operand-codes)
  (let ((operand-codes (reverse operand-codes)))
    (if (null? operand-codes)
        (make-instruction-sequence
         '()
         '(argl)
         '((assign argl (const ()))))
        (let ((code-to-get-last-arg
               (append-instruction-sequences
                (car operand-codes)
                (make-instruction-sequence
                 '(val)
                 '(argl)
                 '((assign argl (op list) (reg val)))))))
          (if (null? (cdr operand-codes))
              code-to-get-last-arg
              (preserving '(env)
                          code-to-get-last-arg
                          (code-to-get-rest-args
                           (cdr operand-codes))))))))

(define (code-to-get-rest-args operand-codes)
  (let ((code-for-next-arg
         (preserving '(argl)
                     (car operand-codes)
                     (make-instruction-sequence
                      '(val argl)
                      '(argl)
                      '((assign argl (op cons) (reg val) (reg argl)))))))
    (if (null? (cdr operand-codes))
        code-for-next-arg
        (preserving '(env)
                    code-for-next-arg
                    (code-to-get-rest-args (cdr operand-codes))))))

(define (compile-procedure-call target linkage compile-time-env)
  (let ((primitive-branch (make-label 'primitive-branch))
        (compiled-branch (make-label 'compiled-branch))
        (after-call (make-label 'after-call)))
    (let ((compiled-linkage
           (if (eq? linkage 'next) after-call linkage)))
      (append-instruction-sequences
       (make-instruction-sequence
        '(proc)
        '()
        `((test (op primitive-procedure?) (reg proc))
          (branch (label ,primitive-branch))))
       (parallel-instruction-sequences
        (append-instruction-sequences
         compiled-branch
         (compile-proc-appl target compiled-linkage))
        (append-instruction-sequences
         primitive-branch
         (end-with-linkage linkage
                           (make-instruction-sequence
                            '(proc argl)
                            (list target)
                            `((assign ,target
                                      (op apply-primitive-procedure)
                                      (reg proc)
                                      (reg argl)))))))
       after-call))))

(define (compile-proc-appl target linkage compile-time-env)
  (cond ((and (eq? target 'val) (not (eq? linkage 'return)))
         (make-instruction-sequence
          '(proc)
          all-regs
          `((assign continue (label ,linkage))
            (assign val
                    (op compiled-procedure-entry)
                    (reg proc))
            (goto (reg val)))))
        ((and (not (eq? target 'val))
              (not (eq? linkage 'return)))
         (let ((proc-return (make-label 'proc-return)))
           (make-instruction-sequence
            '(proc)
            all-regs
            `((assign continue (label ,proc-return))
              (assign val
                      (op compiled-procedure-entry)
                      (reg proc))
              (goto (reg val))
              ,proc-return
              (assign ,target (reg val))
              (goto (label ,linkage))))))
        ((and (eq? target 'val) (eq? linkage 'return))
         (make-instruction-sequence
          '(proc continue)
          all-regs
          '((assign val
                    (op compiled-procedure-entry)
                    (reg proc))
            (goto (reg val)))))
        ((and (not (eq? target 'val)) (eq? linkage 'return))
         (error "return linkage, target not val -- COMPILE" target))))

(define (registers-needed s)
  (if (symbol? s) '() (car s)))

(define (registers-modified s)
  (if (symbol? s) '() (cadr s)))

(define (statements s)
  (if (symbol? s) (list s) (caddr s)))

(define (needs-register? seq reg)
  (memq reg (registers-needed seq)))

(define (modifies-register? seq reg)
  (memq reg (registers-modified seq)))

(define (append-instruction-sequences . seqs)
  (define (append-2-sequences seq1 seq2)
    (make-instruction-sequence
     (list-union (registers-needed seq1)
                 (list-difference (registers-needed seq2)
                                  (registers-needed seq1)))
     (list-union (registers-modified seq1)
                 (registers-modified seq2))
     (append (statements seq1) (statements seq2))))
  (define (append-seq-list seqs)
    (if (null? seqs)
        (empty-instruction-sequence)
        (append-2-sequences (car seqs)
                            (append-seq-list (cdr seqs)))))
  (append-seq-list seqs))

(define (list-union s1 s2)
  (cond ((null? s1) s2)
        ((memq (car s1) s2) (list-union (cdr s1) s2))
        (else (cons (car s1) (list-union (cdr s1) s2)))))

(define (list-difference s1 s2)
  (cond ((null? s1) '())
        ((memq (car s1) s2) (list-difference (cdr s1) s2))
        (else (cons (car s1)
                    (list-difference (cdr s1) s2)))))

(define (preserving regs seq1 seq2)
  (if (null? regs)
      (append-instruction-sequences seq1 seq2)
      (let ((first-reg (car regs)))
        (if (and (needs-register? seq2 first-reg)
                 (modifies-register? seq1 first-reg))
            (preserving (cdr regs)
                        (make-instruction-sequence
                         (list-union (list first-reg)
                                     (registers-needed seq1))
                         (list-difference (registers-modified seq1)
                                          (list first-reg))
                         (append `((save ,first-reg))
                                 (statements seq1)
                                 `((restore ,first-reg))))
                        seq2)
            (preserving (cdr regs) seq1 seq2)))))

(define (tack-on-instruction-sequence seq body-seq)
  (make-instruction-sequence
   (registers-needed seq)
   (registers-modified seq)
   (append (statements seq) (statements body-seq))))

(define (parallel-instruction-sequences seq1 seq2)
  (make-instruction-sequence
   (list-union (registers-needed seq1)
               (registers-needed seq2))
   (list-union (registers-modified seq1)
               (registers-modified seq2))
   (append (statements seq1) (statements seq2))))

compile_time_environment.scm

;; -*- coding: utf-8 -*-

(load "./environment.scm")

;; 文面アドレスの選択子、構成子
(define (lexcal-address-frame-number lexcal-address)
  (car lexcal-address))
(define (lexcal-address-displacement-number lexcal-address)
  (cdr lexcal-address))

(define (make-lexcal-address frame-number displacement-number)
  (cons frame-number displacement-number))

(define (lexical-address-lookup lexcal-address env)
  (let ((frame-number (lexcal-address-frame-number lexcal-address))
        (displacement-number
         (lexcal-address-displacement-number lexcal-address)))
    (let ((frame (list-ref env frame-number)))
      (let ((vals (frame-values frame)))
        (let ((val (list-ref vals displacement-number)))
          (if (eq? val '*unassigned*)
              (let ((vars (frame-variables frame)))
                (error "Unbound variable:"
                       (liset-ref vars displacement-number)))
              val))))))

(define (lexcal-address-set! lexcal-address val env)
  (let ((frame-number (lexcal-address-frame-number lexcal-address))
        (displacement-number
         (lexcal-address-displacement-number lexcal-address)))
    (let ((frame (list-ref env frame-number)))
      (let ((vals (frame-values frame)))
        (define (inner vals n)
          (cond ((null? vals)
                 (error "Unbound variable -- LEXCAL-ADDRESS-SET!"))
                ((= n 0)
                 (set-car! vals val))
                (else (inner (cdr vals) (- n 1)))))
        (inner vals displacement-number)))))
        
(define (extend-compile-time-environment frame base-env)
  (cons frame base-env))

入出力結果(Terminal(gosh), REPL(Read, Eval, Print, Loop))

$ gosh compiler40.scm
$ gosh compile_time_environment.scm
$

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