Operator Precedence Grammar.py

import numpy as np
def stringcheck():
    a=list(input("Enter the operator used in the given grammar including the terminals\n non-treminals should be in cursive(small)letter"))
    a.append('$')
    print(a)
    l=list("abcdefghijklmnopqrstuvwxyz")
    o=list('(/*%+-)')
    p=list('(/*%+-)')
    n=np.empty([len(a)+1,len(a)+1],dtype=str,order="C")
    for j in range(1,len(a)+1):
        n[0][j]=a[j-1]
        n[j][0]=a[j-1]    
    for i in range(1,len(a)+1):
        for j in range(1,len(a)+1):
            if((n[i][0] in l)and(n[0][j] in l)):
                n[i][j]=""
            elif((n[i][0] in l)):
                n[i][j]=">"
            elif((n[i][0] in o) and (n[0][j] in o)):
                if(o.index(n[i][0])<=o.index(n[0][j])):
                   n[i][j]=">"
                else:
                    n[i][j]="<"
            elif((n[i][0] in o)and n[0][j]in l):
                n[i][j]="<"
            elif(n[i][0]=="$" and n[0][j]!="$"):
                n[i][j]="<"
            elif(n[0][j]=="$" and n[i][0]!="$" ):
                 n[i][j]=">"
            else:
                break
    print("The Operator Precedence Relational Table\n=============================================")
    print(n)
    i=list(input("Enter the string want to be checked(non-terminals should be in cursive(small) letter..."))
    i.append("$")
    s=[None]*len(i)
    q=0
    s.insert(q,"$")
    x=[row[0] for row in n]
    y=list(n[0])
    h=0
    while(s[0]!=s[1]):
        if((i[len(i)-2] in p)):
            break
        elif((s[q] in x)and(i[h]in y )):
            if(n[x.index(s[q])][y.index(i[h])]=="<"):
                q+=1
                s.insert(q,i[h])
                h+=1
            elif(n[x.index(s[q])][y.index(i[h])]==">"):
                s.pop(q)
                q-=1
            elif((n[x.index(s[q])][y.index(i[h])]=='')and ((s[q]=="$") and (i[h]=="$"))):
                s[1]=s[0]
        else:
            break
    if(s[0]!=s[1]):
        return False
    else:
        return True
def grammarcheck(i):
    print("Enter the",str(i+1)+"th grammar(production) want to be checked\n For null production please enter any special symbol or whitespace...")
    b=list(input().split("->"))
    f=list("abcdefghijklmnopqrstuvwxyz")
    if(b[0]==" " or b[0]=="" or b[0] in f or len(b)==1):
        return False
    else:
        b.pop(0)
        b=list(b[0])
        s=list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
        o=list("(abcdefghijklmnopqrstuvwxyz^/*+-|)")
        sp=['!','@','#','$','?','~','`',',',';',':','"','=','_','&',"'",""," "]
        for i in range(0,len(b),2):
            if(b[i]==" "):
                g=False
            elif(b[i] in sp):
                g=False
                break
            elif(b[len(b)-1] in o and ((b[0]=="(" and b[len(b)-1]==")" )or (b.count("(")==b.count(")")))):
                g=True
            elif(b[i] in f):
                g=True
            elif(b[len(b)-1] in o):
                g=False
            elif((i==len(b)-1) and (b[i] in s)):
                g=True
            elif((i==len(b)-1) and (b[i] not in s) and (b[i] in o)and b[i-1] in o):
                g=True
            elif((b[i] in s) and(b[i+1]in o)):
                g=True
            elif((b[i] in s) and (b[i+1] in s)):
                g=False
                break
            else:
                g=False
                break
        if(g==True):
            return True
        else:
            return False
c=int(input("Enter the number of LHS variables..\n"))
for i in range(c):
    if(grammarcheck(i)):
        t=True
    else:
        t=False
        break
if(t):
    print("Grammar is accepted")
    if(stringcheck()):
        print("String is accepted")
    else:
        print("String is not accepted")
        
else:
    print("Grammar is not accepted ")