#####################################
                                            |           lexer start             |  //made with flex(GNU) 
                                            #####################################

%{
#include "y.tab.h"
%}

%%

[ \t\n]   {
    /* игнорирование нескольких пробелов подряд, новых строк */
}

"$"[a-zA-Z_][a-zA-Z0-9_]* {
    return IDENTIFIER;
}

\"[^"]*\" {
    return STRING_LITERAL;
}

[0-9]+ {
    return INTEGER;
}

[0-9]+(\.)[0-9]+ {
    return FLOAT;
}

[><]|">="|"<="|"=="|"!=" {
    return COMPARE_OP;
}

"=" {
    return ASSIGN_OP;
}

[-+*/] {
    return ARITH_OPP;
}

"++"|"--" {
    return INC_OP;
}

"("     {
    return L_PAREN;
}

")"     {
    return R_PAREN;
}

"{"     {
    return L_FIG;
}

"}"     {
    return R_FIG;
}

";"     {
    return 0;
}

":"     {
    return COLON;
}

"if"    {
    return IF;
}

"else"  {
    return ELSE;
}

"while"   {
    return WHILE;
}

"for"   {
    return FOR;
}

.       {
    yyerror("invalid character");
}

%%

int yywrap() {
    return 1;
}


                                            #####################################
                                            |           parser start            |  //made with bison(GNU) 
                                            #####################################

%{
#include <stdio.h>

 extern int yylineno;
 extern char *yytext;
 void yyerror(char *);

%}

%token IDENTIFIER

/* statement tokens */
%token IF
%token ELSE
%token WHILE
%token FOR

/* bracket tokens */
%token L_PAREN
%token R_PAREN
%token L_FIG
%token R_FIG

/* tokens */
%token COLON

/* operation tokens */
%token COMPARE_OP
%token ASSIGN_OP
%token ARITH_OPP
%token INC_OP

/* type tokens */
%token INTEGER
%token FLOAT
%token STRING_LITERAL


%%

block:
        | statement
        | L_FIG block R_FIG
;

statement: assign_statement
        | expression
        | if_statement
        | if_else_statement
        | for_loop
        | while_loop
;

expression: arith_expression 
        | logical_expression
;

logical_expression: expression COMPARE_OP expression
;

atom: INTEGER
    | FLOAT
    | STRING_LITERAL
    | IDENTIFIER
;

arith_expression: atom 
    | atom ARITH_OPP arith_expression
;

/*      STATEMENTS START      */
assign_statement: IDENTIFIER ASSIGN_OP expression  { printf("\t\tcorrect ASSIGNMENT statement \n"); }
;

if_statement: IF L_PAREN logical_expression R_PAREN block  { printf("\t\tcorrect IF statement \n"); }
;

if_else_statement: IF L_PAREN logical_expression R_PAREN block ELSE block  { printf("\t\tcorrect IF-ELSE statement statement \n"); }
;

for_loop: FOR L_PAREN arith_expression  logical_expression  arith_expression R_PAREN block  { printf("\t\tcorrect FOR statement \n"); }
;

while_loop: WHILE L_PAREN logical_expression R_PAREN COLON block  { printf("\t\tcorrect WHILE statement \n"); }
;
/*      STATEMENTS END      */

%%

int main() {
    fprintf(stdout, "\n\tThis program receives a text that contains PHP code and checks it\'s correctness\n\n");

     yylineno = 1;

    yyparse();
    fprintf(stdout, "\n\tEnded successfully!\n");
    return 0;
}

void yyerror(char *errmsg)
{
 fprintf(stderr, "\n%s (%d): %s\n", errmsg, yylineno, yytext);
}