Modified genRange() so that it can work on ints and runes

misc.go

@@ -15,6 +15,12 @@ var LPAREN_CHAR rune = 0xF0004 // Parentheses in regex are concatenated with thi
 var RPAREN_CHAR rune = 0xF0005
 var NONCAPLPAREN_CHAR rune = 0xF0006 // Represents a non-capturing group's LPAREN
 var ESC_BACKSLASH rune = 0xF0007     // Represents an escaped backslash
+var CHAR_RANGE rune = 0xF0008        // Represents a character range
+
+// An interface for int and rune, which are identical
+type character interface {
+	int | rune
+}
 
 // Returns true if str[idx] and str[idx-1] are separated by a word boundary.
 func isWordBoundary(str []rune, idx int) bool {
@@ -109,8 +115,8 @@ func Reduce[T any](slc []T, fn func(T, T) T) T {
 }
 
 // Generate numbers in a range - start (inclusive) to end (exclusive)
-func genRange(start, end int) []int {
-	toRet := make([]int, end-start)
+func genRange[T character](start, end T) []T {
+	toRet := make([]T, end-start)
 	for i := start; i < end; i++ {
 		toRet[i-start] = i
 	}