[lib] Update Option to return bool success/fail on parse

lib/util/Option.v3

@@ -20,13 +20,15 @@ class Option<T> extends Opt {
 // The Options class represents a collection of options, each with a name and a value.
 // Any option that has been set to a value other than its default is also remembered.
 class Options(prefix: string) {
-	def map   = Strings.newMap<Opt>();
-	var names = Vector<string>.new();
-	var vals  = Vector<string>.new();
+	def map   = Strings.newMap<Opt>();	// maps names to options
+	var nullOpt: Opt;			// an option with no name
+	var names = Vector<string>.new();	// the names of all parsed options
+	var vals  = Vector<string>.new();	// the values of all options
 	var setUnmatched: (string, string) -> void;
 
 	// Add {option} to the set of options.
 	def add<T>(option: Option<T>) -> Option<T> {
+		if (option.name == null) return nullOpt = option;
 		var name = option.name;
 		if (prefix != null) {
 			name = Strings.builderOf(prefix).putc('.').puts(name).toString();
@@ -51,7 +53,7 @@ class Options(prefix: string) {
 		return [];
 	}
 	// Parse and set a single option from {arg}.
-	def parseOption(arg: string) {
+	def parseOption(arg: string) -> bool {
 		var name: string, val: string;
 		for (i = 1; true; i++) {
 			if (i == arg.length) {
@@ -64,15 +66,20 @@ class Options(prefix: string) {
 				break;
 			}
 		}
-		setOption(name, val);
+		return setOption(name, val);
 	}
-	// Set the option with name {name} to a given value {val}.
-	def setOption(name: string, val: string) {
-		var option = map[name];
-		if (option != null) option.parse(val);
-		else if (setUnmatched != null) setUnmatched(name, val);
+	// Set the option with name {name} to a given value {val}. If {name == null}, then
+	// the {nullOpt} will be set. Returns {true} if the option was successfully set.
+	def setOption(name: string, val: string) -> bool {
 		names.put(name);
 		vals.put(val);
+		var option = if(name == null, nullOpt, map[name]);
+		if (option != null) {
+			option.parse(val);
+			return true;
+		}
+		if (setUnmatched != null) setUnmatched(name, val);
+		return false;
 	}
 }
 // BasicOptions adds a set of utility methods for adding and parsing options