locale: Add localized string, untested resolution function

locale/string.ha

@@ -0,0 +1,59 @@
+// A string localized into multiple locales.
+export type string = [](locale, str);
+
+// Selects the most appropriate localized version of a [[string]] given a
+// [[locale]]. The matching algorithm used is the one specified by the
+// XDG Desktop Entry Specification, §5. Memory is borrowed from the input.
+export fn string_resolve(strin: string, local: locale) (str | void) = {
+	// The matching is done as follows. If LC_MESSAGES is of the form
+	// lang_COUNTRY.ENCODING@MODIFIER, then it will match a key of the form
+	// lang_COUNTRY@MODIFIER. If such a key does not exist, it will attempt
+	// to match lang_COUNTRY followed by lang@MODIFIER. Then, a match
+	// against lang by itself will be attempted. Finally, if no matching key
+	// is found the required key without a locale specified is used. The
+	// encoding from the LC_MESSAGES value is ignored when matching.
+	// 
+	// If LC_MESSAGES does not have a MODIFIER field, then no key with a
+	// modifier will be matched. Similarly, if LC_MESSAGES does not have a
+	// COUNTRY field, then no key with a country specified will be matched.
+	// If LC_MESSAGES just has a lang field, then it will do a straight
+	// match to a key with a similar value.
+	
+	let lang_country_modifier = local;
+	lang_country_modifier.encoding = "";
+	match (string_resolve_exact(strin, lang_country_modifier)) {
+	case let index: size => return index;
+	case                 => void;
+	};
+	
+	let lang_country = local;
+	lang_country.modifier = "";
+	match (string_resolve_exact(strin, lang_country)) {
+	case let index: size => return index;
+	case                 => void;
+	};
+	
+	let lang_modifier = lang_country_modifier;
+	lang_modifier.country = "";
+	match (string_resolve_exact(strin, lang_modifier)) {
+	case let index: size => return index;
+	case                 => void;
+	};
+
+	let lang = lang_modifier;
+	lang.modifier = "";
+	match (string_resolve_exact(strin, lang)) {
+	case let index: size => return index;
+	case                 => void;
+	};
+	
+	return void;
+};
+
+fn string_resolve_exact(strin: string, local: locale) (size | void) = {
+	let index = 0z;
+	for (let pair .. strn) {
+		if(equal(pair.1, local)) return index;
+		index += 1;
+	};
+};