Updated more referencs to constants

regex/compile.go

@@ -768,7 +768,7 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
 			// Keep popping from opStack until we encounter an opening parantheses or a NONCAPLPAREN_CHAR. Throw error if we reach the end of the stack.
 			var val rune
 			var err error
-			for val, err = peek(opStack); val != '(' && val != NONCAPLPAREN_CHAR; val, err = peek(opStack) {
+			for val, err = peek(opStack); val != '(' && val != nonCapLparenRune; val, err = peek(opStack) {
 				if err != nil {
 					return nil, fmt.Errorf("imbalanced parantheses")
 				}

regex/range2regex.go

@@ -115,7 +115,7 @@ func range2regex(start int, end int) (string, error) {
 			if startSlc[i] == endSlc[i] {
 				regex += string(rune(startSlc[i] + 48)) // '0' is ascii value 48, 1 is 49 etc. To convert the digit to its character form, we can just add 48.
 			} else {
-				regex += fmt.Sprintf("%c%c-%c%c", lbracketRune, rune(startSlc[i]+48), rune(endSlc[i]+48), RBRACKET)
+				regex += fmt.Sprintf("%c%c-%c%c", lbracketRune, rune(startSlc[i]+48), rune(endSlc[i]+48), rbracketRune)
 			}
 		}
 		regex += ")"