implement lexical analysis function for c-minus

src/test.cm

@@ -0,0 +1,16 @@
+/* A program to perform Euclid's
+    Algorithm to compute gcd */
+
+int gcd(int u, int v)
+{
+    if(v == 0) return u;
+    else return gcd(v, u- u/v * v);
+    /* hello u-u/v*v == u mod v */
+}
+
+void main()
+{
+    int x; int y;
+    x = input(); y = input();
+    print(gcd(x, y));
+}