$\%\{$

#include

#include

#include

#define INTEGER $1$

#define STRING $2$

#define IDENTIFIER $3$

#define READ $4$

#define PRINT $5$

#define IF $6$

#define THEN $7$

#define ELSE $8$

#define DO $9$

#define PROGRAM $10$

#define END $11$

#define GT $12$

#define LT $13$

#define EQ $14$

$\%\}$

$\%\%$

"PROGRAM" return PROGRAM;

"INTEGER" return INTEGER;

"READ" return READ;

"PRINT" return PRINT;

$"$IF$"$ return IF;

"THEN" return THEN;

"ELSE" return ELSE;

$"$DO$"$ return DO;

"END" return END;

$".$GT$."$ return GT;

$".$LT$."$ return LT;

$".$EQ$."$ return EQ;

$[0-9]+\{$ yylval $=$ atoi$($yytext$)$; return INTEGER; $\}$

$[$a$-$z$]+\{$ yylval $=$ strdup$($yytext$)$; return IDENTIFIER; $\}$

$\backslash "[^\backslash "]*\backslash "\{$ yylval $=$ strdup$($yytext$)$; return STRING; $\}$

$"="$ return $\text{'}=\text{'}$;

$"+"$ return $\text{'}+\text{'}$;

$"-"$ return $\text{'}-\text{'}$;

$"("$ return $\text{'}(\text{'}$;

$")"$ return $\text{'})\text{'}$;

$","$ return $\text{'},\text{'}$;

$"*"$ return $\text{'}*\text{'}$;

$[$

$]+\{/*$ Ignore new lines $*/\}$

$[\backslash$t$]+\{/*$ Ignore whitespaces $*/\}$

$"!"[^$

$]*\{/*$ Ignore comments $*/\}$

$.\{$ printf$("$Unrecognized token: $\%$s

$",$ yytext$)$; exit$(1)$; $\}$

$\%\%$

int yywrap$()\{$

return $1$;

$\}$

Write a flex specification for the language of F$15$ using the lexical grammar.

$1.$ the lexer.l file is already provided

$2.$ Write your main$()($in a separate file FirstName$\_$LastName$\_$A$2.$c$)$ to test your lexer.

$3.$ Prepare a Makefile to compile the specifications and generate the lexer.

$4.$ Prepare a test input file FirstName$\_$LastName$\_$A$2.$nc that will test all the lexical rules that you have

coded.

$5.$ Prepare a FirstName$\_$LastName$\_$A$2.$pdf file explaining the working of your lexer and your design