aoc-2022/day_2-2/lexer.l

%{
#include <stdio.h>
#include <stdlib.h>
#include "parser.h"
%}

%option warn nodefault

/* makes the scanner terminate after reaching <<EOF>> instead of assuming a new input was provided */
%option noyywrap
/* disable some unused functionality, add scanner tracking */
%option nounput noinput batch debug

/* gimme a reentrant parser (overkill but more pure) */
%option reentrant

%option bison-bridge


NL      [\n]
SPACE   [ \t]
ROCK    [A]
PAPER   [B]
SCISSOR [C]
LOSS    [X]
DRAW    [Y]
WIN     [Z]

%%

{NL}        { return NEWLINE; }
{SPACE}+    { /* don't care */}
{ROCK}      { return ROCK; }
{PAPER}     { return PAPER; }
{SCISSOR}   { return SCISSOR; }
{LOSS}      { return LOSS; }
{DRAW}      { return DRAW; }
{WIN}       { return WIN; }
<<EOF>>     { return END_OF_FILE; }
.           {
                printf("[error] Encountered unexpected token %s\n", yytext);
                return 0;
            }

%%