LISP-将语法输入转换为字符串(语言理论)
我实现了一个问题,该问题从语法(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-终端集和P-生产规则,以及S-开始符号LISP-将语法输入转换为字符串(语言理论),lisp,common-lisp,clisp,Lisp,Common Lisp,Clisp,我实现了一个问题,该问题从语法(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-终端集和P-生产规则,以及S-开始符号 ; 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
; 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,这是我想问的唯一问题,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”、“*”和“begin”等中使用类似的东西
提前感谢您……您可以使用符号:|这仍然是一个符号,保留其大小写|
|m和m都是符号。不同的符号。@e20:你可以用你的语法写| m |和m。这两个都是不同的符号,它们不是相等的。我看到了读卡器表的默认设置。也就是说,
D'和
D'是相同的符号,都是大写。我需要使用\(反斜杠)或| |(围绕符号名称的管道以保留大小写)。例如.\d是小写的d'。类似地,| d |是小写的
d'。难道你不知道在LISP中是否还有其他的解决方案吗?你总是可以使用Fortran语言。A、 B,C。。。是非终结符。终端从I,J,K开始。上帝不是终端,除非声明为终端!请