SICP 3.2 評価の環境モデル
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; ex-3.9 ; ; 再帰版 ; _____________________________________ ; 大域領域 -> | | ; ------------------------------------- ; ↑ ↑ ↑ ; E1→|n:3| E2→|n:2| E3→|n:1| ; (if (= n 1) ; 1 ; (* n (factorial (- n 1)))) ; E1 ~ E1同じ↑ ; ; 反復版 ; _____________________________________ ; 大域領域 -> | | ; ------------------------------------- ; ↑ ; E1→|n:3| ; (fact-iter 1 1 n) ; ↑ ; E2→|product:1 | ; |counter:1 | ; |max-count:3| ; (fact-iter (* counter product) ; (+ counter 1) ; max-count) ; ; E3 product:1, counter:2, max-count:6 ; E4 product:2, counter:3, max-count:6 ; E5 product:6, counter:4, max-count:6 ; E6 product:24, counter:5, max-count:6 ; E6 product:120, counter:6, max-count:6 ; E6 product:720, counter:7, max-count:6 ; ex-3.10 ; ; (define W1 (make-withdraw 100)) ; (W1 50) ; (define W2 (make-withdraw 100)) ;--------------------------------------------- ; ; (define W1 (make-withdraw 100)) ; _____________________________________________________________________ ; 大域領域 -> |make-withdraw: | ; |W1: | ; --------------------------------------------------------------------- ; ↑ ↓(W1) ↑ ↑(make-withdraw:) ; E1→|initial-balance:100| OO--->E2→|balance:100| OO ; ↓ ↓ ; パラメタ: amount パラメタ:initial-amount ; 本体: (lambda (amount)... 本体: (lambda (balance)... ; ; (W1 50) ; _____________________________________________________________________ ; 大域領域 -> |make-withdraw: | ; |W1: | ; --------------------------------------------------------------------- ; ↓(W1) ↑ ; OO-------->E2→|balance:100| ; ↓ ↑ ; パラメタ: |amount: 50| ; 本体: ; ; _____________________________________________________________________ ; 大域領域 -> |make-withdraw: | ; |W1: | ; --------------------------------------------------------------------- ; ↓(W1) ↑ ; OO-------->E2→|balance:50| ; ↓ ; パラメタ: ; 本体: ; ; (define W2 (make-withdraw 100)) ; _____________________________________________________________________ ; 大域領域 -> |make-withdraw: | ; |W1: | ; |W2: | ; --------------------------------------------------------------------- ; ↓(W1) ↑ ↑ ↓(W2) ↑ ; OO-------->E2→|balance:50| E3|initial-balance:100| OO--->E4|balance:100| ; ↓ ↓ ; パラメタ: パラメタ: amount ; 本体: 本体: (lambda (amount)... ; memo: ; defineされた時にOO(対になるオブジェクト) が作られる. ; 評価された時に環境が作られるが作られる. ; ex-3.11 ; ; (define acc (make-account 50)) ; ; ((acc 'deposit) 40) ; 90 ; ; ((acc 'withdraw) 60) ; 30 ; ; (define acc2 (make-account 100)) ;--------------------------------------------- ; ; (define acc (make-account 50)) ; _____________________________________________________________________ ; 大域領域 -> |make-account: ; |acc: ; --------------------------------------------------------------------- ; ↑↓(make-account) ↓(acc) ↑ ____________ ; OO OO--------------------→E1→|balance:50| ; ↓ ↓ |withdraw: |<->OO->パラメタ:amount, 本体: (if (>= balance amount) ... ; パラメタ: balance: パラメタ: m |deposit: |<->OO->パラメタ:amount, 本体: (set! balance ... ; 本体: (define (withdraw ... 本体: (cond ((eq? ... |dispatch: |<->OO->パラメタ:m, 本体: (cond ((eq? ... ; ; ; ((acc 'deposit) 40) ; _____________________________________________________________________ ; 大域領域 -> |make-account: ; |acc: ; --------------------------------------------------------------------- ; ↑↓(make-account) ↓(acc) ↑ ___________ ; OO OO--------------------→E1→|balance:90| ; ↓ ↓ |withdraw: |<->OO->パラメタ:amount, 本体: (if (>= balance amount) ... ; パラメタ: balance: パラメタ: m |deposit: |<->OO->パラメタ:amount, 本体: (set! balance ... ; 本体: (define (withdraw ... 本体: (cond ((eq? ... |dispatch: |<->OO->パラメタ:m, 本体: (cond ((eq? ... ; ------------ ; ↑ ↑ ; E2→|m: 'deposit| E3→|amount: 40| ; ((acc 'withdraw) 60) ; _____________________________________________________________________ ; 大域領域 -> |make-account: ; |acc: ; --------------------------------------------------------------------- ; ↑↓(make-account) ↓(acc) ↑ ___________ ; OO OO--------------------→E1→|balance:30| ; ↓ ↓ |withdraw: |<->OO->パラメタ:amount, 本体: (if (>= balance amount) ... ; パラメタ: balance: パラメタ: m |deposit: |<->OO->パラメタ:amount, 本体: (set! balance ... ; 本体: (define (withdraw ... 本体: (cond ((eq? ... |dispatch: |<->OO->パラメタ:m, 本体: (cond ((eq? ... ; ------------ ; ↑ ↑ ; E4→|m: 'withdraw| E5→|amount: 60| ; ; ; (define acc2 (make-account 100)) ; _____________________________________________________________________ ; 大域領域 -> |make-account: ; |acc: ; |acc2: ; --------------------------------------------------------------------- ; ↑↓(make-account) ↓(acc) ↑ ____________ ; OO OO--------------------→E1→|balance:50| ; ↓ ↓ |withdraw: |<->OO->パラメタ:amount, 本体: (if (>= balance amount) ... ; パラメタ: balance: パラメタ: m |deposit: |<->OO->パラメタ:amount, 本体: (set! balance ... ; 本体: (define (withdraw ... 本体: (cond ((eq? ... |dispatch: |<->OO->パラメタ:m, 本体: (cond ((eq? ... ; ; ↓(acc2) ↑(大域) ; OO--------------------→E6→|balance:100| ; ↓ |withdraw: |<->OO->パラメタ:amount, 本体: (if (>= balance amount) ... ; パラメタ: m |deposit: |<->OO->パラメタ:amount, 本体: (set! balance ... ; 本体: (cond ((eq? ... |dispatch: |<->OO->パラメタ:m, 本体: (cond ((eq? ...
