Added different functions for casting to integers and strings

builtin/string.v

@@ -138,16 +138,31 @@ pub fn (s string) replace(rep, with string) string {
 	return tos(b, new_len)
 }
 
-// TODO `.int()` ?
-pub fn (s string) to_i() int {
+// Casting to numbers (integers and floats)
+fn (s string) to_i() int {
 	return C.atoi(s.str)
 }
 
-// TODO `.f32()`
+fn (s string) int() int {
+	return s.to_i()
+}
+
+fn (s string) i32() int {
+	return s.to_i()
+}
+
 fn (s string) to_float() float {
 	return C.atof(s.str)
 }
 
+fn (s string) float() float {
+	return s.to_float()
+}
+
+fn (s string) f32() float {
+	return s.to_float()
+}
+
 // ==
 fn (s string) eq(a string) bool {
 	if isnil(s.str) {