gpt4 book ai didi

LISP - 将语法输入转换为字符串(语言理论)

转载 作者:太空宇宙 更新时间:2023-11-03 18:48:47 25 4
gpt4 key购买 nike

我已经实现了一个问题,它从语法 (Vn;Vt;P;S) 中确定非生产性或不可访问的元素,其中 Vn - 变量集; Vt- 一组终端和 P - 产生式规则,以及 S - 起始符号。

; Defining a grammar
(defvar *VN* '(A B C D S)) ; non-terminal variables
(defvar *VT* '(k m n)) ; terminal
(defvar *P* '((S A B) ; set of production rules
(S C D)
(S A k)
(A k)
(B m)
(B D m D)
(C n)
)
)

;;; FINDING PRODUCTIVE ELEMENTS
(defun PROD-STEP (VT P PRODS)
;(format t "P = ~S~%" P)
;(format t "PRODS = ~S~%" PRODS)
(if (null P) PRODS
(if (subsetp (rest (first P)) (union VT PRODS))
(PROD-STEP VT (rest P) (union (cons (first (first P)) nil) PRODS))
(PROD-STEP VT (rest P) PRODS)
)
)
)
(defun PROD-AUX (VT P PRODS oldLength)
(if (= (length PRODS) oldLength)
PRODS
(PROD-AUX VT P (PROD-STEP VT P PRODS) (length PRODS))
)
)

(defun PROD (VT P)
(PROD-AUX VT P nil -1)
)
;;; END OF FINDING PROD ELEMENTS

(trace PROD-STEP)
(trace PROD-AUX)
(trace PROD)
(PROD *VT* *P*)


;;; FINDING ACCESSIBLE ELEMENTS
(defun ACCESS-STEP (P ACC)
;(format t "Pacc = ~S~%" P)
;(format t "ACC = ~S~%" ACC)
(if (null P) ACC
(if (member (first (first P)) ACC)
(ACCESS-STEP (rest P) (union (rest (first P)) ACC))
(ACCESS-STEP (rest P) ACC)
)
)
)

(defun ACCESS-AUX (P ACC oldLength)
(if (= (length ACC) oldLength)
ACC
(ACCESS-AUX P (ACCESS-STEP P ACC) (length ACC))
)
)
(defun ACCESS (P S)
;(format t "Paccess = ~S~%" P)
(ACCESS-AUX P (cons S nil) 0)
)
;;; END OF FINDING ACCESSIBLE ELEMENTS

(trace ACCESS-STEP)
(trace ACCESS-AUX)
(trace ACCESS)
(ACCESS *P* 'S)

;;; REMOVING INACCESSIBLE AND NOT PRODUCTIVE ELEMENTS
(defun BuildRules-AUX (VT ACCS PRODS P newP)
;(format t "newP = ~S~%" newP)
(if (null P) newP
; VN' = (ACCESS(G) INTERSECT PROD(G))
; VT' = (VT INTERSECT ACCESS(G))
; DACA REGULA ESTE A->X, A = (first (first P)) SI X = (rest (first P))
; VERIFICAM DACA A APARTINE VN' SI X APARTINE (VT' UNION VN')
(if (and (member (first (first P)) (intersection PRODS ACCS)) (subsetp (rest (first P)) (union (intersection ACCS PRODS) (intersection VT ACCS)) ))
(BuildRules-AUX VT ACCS PRODS (rest P) (union newP (cons (first P) nil)))
(BuildRules-AUX VT ACCS PRODS (rest P) newP)
)
)
)

(defun BuildRules (VT ACCS PRODS P)
(BuildRules-AUX VT ACCS PRODS P nil)
)
(trace BuildRules-AUX)
(trace BuildRules)

(BuildRules *VT* (ACCESS *P* 'S) (PROD *VT* *P*)*P*)

(defun SIMPL-AUX (VN VT P S ACCS PRODS)
(setq ACCS (ACCESS P S))
(setq PRODS (PROD VT P))
(if (and (null (set-difference (union VN VT) ACCS)) (null (set-difference VN PRODS)))
(cons VN (cons VT (cons P S)))
(SIMPL-AUX
(intersection ACCS PRODS)
(intersection VT ACCS)
(BuildRules VT ACCS PRODS P)
S
ACCS
PRODS
)
)
)
(defun SIMPL (VN VT P S)
(SIMPL-AUX *VN* *VT* *P* 'S nil nil)
)
;;; END OF REMOVING INACCESSIBLE AND NOT PRODUCTIVE ELEMENTS

;;; GETTING THE RESULTS
(SIMPL *VN* *VT* *P* 'S)

程序按预期工作,我想问的唯一问题是如何将输入数据转换为字符串,因为我想区分“a”终端和“A”非终端。

我想我应该在输入“a”、“k”、“*”、“begin”等中使用类似的东西。

提前致谢...

最佳答案

你可以使用符号:|这仍然是一个符号,保持大小写|

|米|和 M 都是符号。不同的符号。

关于LISP - 将语法输入转换为字符串(语言理论),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10394738/

25 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com