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SLR_parse_table.cpp
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SLR_parse_table.cpp
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#include<iostream>
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
using namespace std;
char terminals[100]={};int no_t;
char non_terminals[100]={};int no_nt;
char goto_table[100][100];
char reduce[20][20];
char follow[20][20];char fo_co[20][20];
char first[20][20];
struct state{
int prod_count;
char prod[100][100]={{}};
};
void add_dots(struct state *I){
for(int i=0;i<I->prod_count;i++){
for (int j=99;j>3;j--)
I->prod[i][j] = I->prod[i][j-1];
I->prod[i][3]='.';
}
}
void augument(struct state *S,struct state *I){
if(I->prod[0][0]=='S')
strcpy(S->prod[0],"Z->.S");
else{
strcpy(S->prod[0],"S->.");
S->prod[0][4]=I->prod[0][0];}
S->prod_count++;
}
void get_prods(struct state *I){
cout<<"Enter the number of productions:\n";
cin>>I->prod_count;
cout<<"Enter the number of non terminals:"<<endl;
cin>>no_nt;
cout<<"Enter the non terminals one by one:"<<endl;
for(int i=0;i<no_nt;i++)
cin>>non_terminals[i];
cout<<"Enter the number of terminals:"<<endl;
cin>>no_t;
cout<<"Enter the terminals (single lettered) one by one:"<<endl;
for(int i=0;i<no_t;i++)
cin>>terminals[i];
cout<<"Enter the productions one by one in form (S->ABc):\n";
for(int i=0;i<I->prod_count;i++){
cin>>I->prod[i];
}
}
bool is_non_terminal(char a){
if (a >= 'A' && a <= 'Z')
return true;
else
return false;
}
bool in_state(struct state *I,char *a){
for(int i=0;i<I->prod_count;i++){
if(!strcmp(I->prod[i],a))
return true;
}
return false;
}
char char_after_dot(char a[100]){
char b;
for(int i=0;i<strlen(a);i++)
if(a[i]=='.'){
b=a[i+1];
return b;}
}
char* move_dot(char b[100],int len){
char a[100]={};
strcpy(a,b);
for(int i=0;i<len;i++){
if(a[i]=='.'){
swap(a[i],a[i+1]);
break;
}
}
return &a[0];
}
bool same_state(struct state *I0,struct state *I){
if (I0->prod_count != I->prod_count)
return false;
for (int i=0; i<I0->prod_count; i++)
{
int flag = 0;
for (int j=0; j<I->prod_count; j++)
if (strcmp(I0->prod[i], I->prod[j]) == 0)
flag = 1;
if (flag == 0)
return false;
}
return true;
}
void closure(struct state *I,struct state *I0){
char a={};
for(int i=0;i<I0->prod_count;i++){
a=char_after_dot(I0->prod[i]);
if(is_non_terminal(a)){
for(int j=0;j<I->prod_count;j++){
if(I->prod[j][0]==a){
if(!in_state(I0,I->prod[j])){
strcpy(I0->prod[I0->prod_count],I->prod[j]);
I0->prod_count++;
}
}
}
}
}
}
void goto_state(struct state *I,struct state *S,char a){
int time=1;
for(int i=0;i<I->prod_count;i++){
if(char_after_dot(I->prod[i])==a){
if(time==1){
time++;
}
strcpy(S->prod[S->prod_count],move_dot(I->prod[i],strlen(I->prod[i])));
S->prod_count++;
}
}
}
void print_prods(struct state *I){
for(int i=0;i<I->prod_count;i++)
printf("%s\n",I->prod[i]);
cout<<endl;
}
bool in_array(char a[20],char b){
for(int i=0;i<strlen(a);i++)
if(a[i]==b)
return true;
return false;
}
char* chars_after_dots(struct state *I){
char a[20]={};
for(int i=0;i<I->prod_count;i++){
if(!in_array(a,char_after_dot(I->prod[i]))){
a[strlen(a)]=char_after_dot(I->prod[i]);
}
}
return &a[0];
}
void cleanup_prods(struct state * I){
char a[100]={};
for(int i=0;i<I->prod_count;i++)
strcpy(I->prod[i],a);
I->prod_count=0;
}
int return_index(char a){
for(int i=0;i<no_t;i++)
if(terminals[i]==a)
return i;
for(int i=0;i<no_nt;i++)
if(non_terminals[i]==a)
return no_t+i;
}
void print_shift_table(int state_count){
cout<<endl<<"********Shift Actions*********"<<endl<<endl;
cout<<"\t";
for(int i=0;i<no_t;i++)
cout<<terminals[i]<<"\t";
for(int i=0;i<no_nt;i++)
cout<<non_terminals[i]<<"\t";
cout<<endl;
for(int i=0;i<state_count;i++){
int arr[no_nt+no_t]={-1};
for(int j=0;j<state_count;j++){
if(goto_table[i][j]!='~'){
arr[return_index(goto_table[i][j])]= j;
}
}
cout<<"I"<<i<<"\t";
for(int j=0;j<no_nt+no_t;j++){
if(i==1&&j==no_t-1)
cout<<"ACC"<<"\t";
if(arr[j]==-1||arr[j]==0)
cout<<"\t";
else{
if(j<no_t)
cout<<"S"<<arr[j]<<"\t";
else
cout<<arr[j]<<"\t";
}
}
cout<<"\n";
}
}
int get_index(char c,char *a){
for(int i=0;i<strlen(a);i++)
if(a[i]==c)
return i;
}
void add_dot_at_end(struct state* I){
for(int i=0;i<I->prod_count;i++){
strcat(I->prod[i],".");
}
}
void add_to_first(int n,char b){
for(int i=0;i<strlen(first[n]);i++)
if(first[n][i]==b)
return;
first[n][strlen(first[n])]=b;
}
void add_to_first(int m,int n){
for(int i=0;i<strlen(first[n]);i++){
int flag=0;
for(int j=0;j<strlen(first[m]);j++){
if(first[n][i]==first[m][j])
flag=1;
}
if(flag==0)
add_to_first(m,first[n][i]);
}
}
void add_to_follow(int n,char b){
for(int i=0;i<strlen(follow[n]);i++)
if(follow[n][i]==b)
return;
follow[n][strlen(follow[n])]=b;
}
void add_to_follow(int m,int n){
for(int i=0;i<strlen(follow[n]);i++){
int flag=0;
for(int j=0;j<strlen(follow[m]);j++){
if(follow[n][i]==follow[m][j])
flag=1;
}
if(flag==0)
add_to_follow(m,follow[n][i]);
}
}
void add_to_follow_first(int m,int n){
for(int i=0;i<strlen(first[n]);i++){
int flag=0;
for(int j=0;j<strlen(follow[m]);j++){
if(first[n][i]==follow[m][j])
flag=1;
}
if(flag==0)
add_to_follow(m,first[n][i]);
}
}
void find_first(struct state *I){
for(int i=0;i<no_nt;i++){
for(int j=0;j<I->prod_count;j++){
if(I->prod[j][0]==non_terminals[i]){
if(!is_non_terminal(I->prod[j][3])){
add_to_first(i,I->prod[j][3]);
}
}
}
}
}
void find_follow(struct state *I){
for(int i=0;i<no_nt;i++){
for(int j=0;j<I->prod_count;j++){
for(int k=3;k<strlen(I->prod[j]);k++){
if(I->prod[j][k]==non_terminals[i]){
if(I->prod[j][k+1]!='\0'){
if(!is_non_terminal(I->prod[j][k+1])){
add_to_follow(i,I->prod[j][k+1]);
}
}
}
}
}
}
}
int get_index(int *arr,int n){
for(int i=0;i<no_t;i++){
if(arr[i]==n)
return i;
}
return -1;
}
void print_reduce_table(int state_count,int *no_re,struct state *temp1){
cout<<"**********Reduce actions**********"<<endl<<endl;
cout<<"\t";
int arr[temp1->prod_count][no_t]={-1};
for(int i=0;i<no_t;i++){
cout<<terminals[i]<<"\t";
}
cout<<endl;
for(int i=0;i<temp1->prod_count;i++){
int n=no_re[i];
for(int j=0;j<strlen(follow[return_index(temp1->prod[i][0])-no_t]);j++){
for(int k=0;k<no_t;k++){
if(follow[return_index(temp1->prod[i][0])-no_t][j]==terminals[k])
arr[i][k]=i+1;
}
}
cout<<"I"<<n<<"\t";
for(int j=0;j<no_t;j++){
if(arr[i][j]!=-1&&arr[i][j]!=0&&arr[i][j]<state_count)
cout<<"R"<<arr[i][j]<<"\t";
else
cout<<"\t";
}
cout<<endl;
}
}
int main(){
struct state init;
struct state temp;struct state temp1;
int state_count=1;
get_prods(&init);
temp=init;
temp1=temp;
add_dots(&init);
for(int i=0;i<100;i++)
for(int j=0;j<100;j++)
goto_table[i][j]='~';
struct state I[50];
augument(&I[0],&init);
closure(&init,&I[0]);
cout<<"\nI0:\n";
print_prods(&I[0]);
char characters[20]={};
for(int i=0;i<state_count;i++){
char characters[20]={};
for(int z=0;z<I[i].prod_count;z++)
if(!in_array(characters,char_after_dot(I[i].prod[z])))
characters[strlen(characters)]=char_after_dot(I[i].prod[z]);
for(int j=0;j<strlen(characters);j++){
goto_state(&I[i],&I[state_count],characters[j]);
closure(&init,&I[state_count]);
int flag=0;
for(int k=0;k<state_count-1;k++){
if(same_state(&I[k],&I[state_count])){
cleanup_prods(&I[state_count]);flag=1;
cout<<"I"<<i<<" on reading the symbol "<<characters[j]<<" goes to I"<<k<<".\n";
goto_table[i][k]=characters[j];;
break;
}
}
if(flag==0){
state_count++;
cout<<"I"<<i<<" on reading the symbol "<<characters[j]<<" goes to I"<<state_count-1<<":\n";
goto_table[i][state_count-1]=characters[j];
print_prods(&I[state_count-1]);
}
}
}
int no_re[temp.prod_count]={-1};
terminals[no_t]='$';no_t++;
add_dot_at_end(&temp1);
for(int i=0;i<state_count;i++){
for(int j=0;j<I[i].prod_count;j++)
for(int k=0;k<temp1.prod_count;k++)
if(in_state(&I[i],temp1.prod[k]))
no_re[k]=i;
}
find_first(&temp);
for(int l=0;l<no_nt;l++){
for(int i=0;i<temp.prod_count;i++){
if(is_non_terminal(temp.prod[i][3])){
add_to_first(return_index(temp.prod[i][0])-no_t,return_index(temp.prod[i][3])-no_t);
}
}}
find_follow(&temp);
add_to_follow(0,'$');
for(int l=0;l<no_nt;l++){
for(int i=0;i<temp.prod_count;i++){
for(int k=3;k<strlen(temp.prod[i]);k++){
if(temp.prod[i][k]==non_terminals[l]){
if(is_non_terminal(temp.prod[i][k+1])){
add_to_follow_first(l,return_index(temp.prod[i][k+1])-no_t);}
if(temp.prod[i][k+1]=='\0')
add_to_follow(l,return_index(temp.prod[i][0])-no_t);
}
}
}
}
print_shift_table(state_count);
cout<<endl<<endl;
print_reduce_table(state_count,&no_re[0],&temp1);
}