yacclex/calclexret/calc.l


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%{
enum yytokentype {
	NUMBER = 258,
	ADD = 259,
	SUB = 260,
	MUL = 261,
	DIV = 262,
	ABS = 263,
	EOL = 264
};

int yylval;
%}

%%
"+"    { return ADD;                                }
"-"    { return SUB;                                }
"*"    { return MUL;                                }
"/"    { return DIV;                                }
"|"    { return ABS;                                }
[0-9]+ { yylval = atoi(yytext); return NUMBER;      }
\n     { return EOL;                                }
[ \t]  { /* ignore whitespace */                    }
.      { printf("Mystery character %c\n", *yytext); }
%%

int yywrap() {
	return 1;
}

int main(void) {
	int tok;
	while((tok = yylex())) {
		printf("%d", tok);
		if(tok == NUMBER)
			printf(" = %d\n", yylval);
		else printf("\n");
	}
}