initial commit recognizing tokens

1 files changed, 68 insertions, 0 deletions

diff --git a/expr.l b/expr.l
new file mode 100644
index 0000000..7612ebf
--- /dev/null
+++ b/expr.l
@@ -0,0 +1,68 @@
+%{
+#define _XOPEN_SOURCE 2
+#include <locale.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include "expr.h"
+%}
+
+DIGIT [0-9]
+
+%%
+
+"|"	puts("or");
+"&"	puts("and");
+"="	puts("equal");
+">"	puts("greater");
+">="	puts("greater or equal");
+"<"	puts("less");
+"<="	puts("less or equal");
+"!="	puts("not equal");
+"+"	puts("plus");
+"-"	puts("minus");
+"*"	puts("times");
+"/"	puts("divide");
+"%"	puts("remainder");
+"("	puts("lparen");
+")"	puts("rparen");
+{DIGIT}+	printf("number %s\n", yytext);
+-{DIGIT}+	printf("negative %s\n", yytext);
+.+		printf("string '%s'\n", yytext);
+
+%%
+
+int main(int argc, char *argv[])
+{
+	setlocale(LC_ALL, "");
+
+	int c;
+	while ((c = getopt(argc, argv, "")) != -1) {
+		switch (c) {
+		default:
+			return -1;
+		}
+	}
+
+	if (optind >= argc) {
+		fprintf(stderr, "expr: missing operands\n");
+		return 1;
+	}
+
+	size_t n = 1;
+	for (int i = optind; i < argc; i++) {
+		n += strlen(argv[i]) + 1;
+	}
+
+	FILE *mem = fmemopen(NULL, n, "w+");
+	for (int i = optind; i < argc; i++) {
+		fprintf(mem, "%s\n", argv[i]);
+	}
+	fprintf(mem, "\n");
+	rewind(mem);
+
+	yyin = mem;
+
+
+	return yylex();
+}