Store multiline mode as a global flag

compile.go

@@ -77,6 +77,9 @@ func getPOSIXClass(str []rune) (bool, string) {
 // Stores whether the case-insensitive flag has been enabled.
 var caseInsensitive bool
 
+// Stores whether the multiline flag has been enabled.
+var multilineMode bool
+
 /*
 The Shunting-Yard algorithm is used to convert the given infix (regeular) expression to postfix.
 The primary benefit of this is getting rid of parentheses.
@@ -89,9 +92,11 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
 	// Check which flags are enabled
 
 	caseInsensitive = false
+	multilineMode = false
 	// In Multiline mode, the newline character is considered a
 	// 'dot' character ie. the dot metacharacter matches a newline as well.
 	if slices.Contains(flags, RE_MULTILINE) {
+		multilineMode = true
 		notDotChars = []rune{}
 	} else {
 		notDotChars = []rune{'\n'}