Added dev target in makefile, added regexp-dispatch and example

source/text/regexp.mjs

@@ -0,0 +1,49 @@
+export function get_flags(pattern) {
+	if (pattern instanceof RegExp) {
+		return new Set(pattern.flags);
+	} else {
+		return new Set();
+	}
+}
+export function get_source(pattern) {
+	if (pattern instanceof RegExp) {
+		return pattern.source;
+	} else {
+		return pattern;
+	}
+}
+
+export function concat(...pattern_list) {
+	let pending_source = '';
+	const pending_flags = new Set();
+
+	for (const pattern of pattern_list) {
+
+		if (pattern instanceof RegExp) {
+			pending_source += pattern.source;
+			for (const flag of pattern.flags) {
+				pending_flags.add(flag);
+			}
+		} else {
+			pending_source += pattern;
+		}
+	}
+
+	return new RegExp(pending_source, String.prototype.concat(...pending_flags));
+}
+
+
+export function join(pattern_list, separator, flags=undefined) {
+	return new RegExp(pattern_list.map(pattern => get_source(pattern)).join(get_source(separator)), flags);
+}
+
+
+export function update_flag(pattern, flag, state) {
+	const pattern_flags = get_flags(pattern);
+	if (state) {
+		pattern_flags.add(flag);
+	} else {
+		pattern_flags.delete(flag);
+	}
+	return new RegExp(pattern.source, String.prototype.concat(...pattern_flags));
+}