[xml] Improvements.

core/encoding/xml/helpers.odin

@@ -0,0 +1,49 @@
+package xml
+/*
+	An XML 1.0 / 1.1 parser
+
+	Copyright 2021 Jeroen van Rijn <nom@duclavier.com>.
+	Made available under Odin's BSD-3 license.
+
+	This file contains helper functions.
+*/
+
+
+/*
+	Find `tag`'s nth child with a given ident.
+*/
+find_child_by_ident :: proc(tag: ^Element, ident: string, nth := 0) -> (res: ^Element, found: bool) {
+	if tag == nil                                 { return nil, false }
+
+	count := 0
+	for child in tag.children {
+		/*
+			Skip commments. They have no name.
+		*/
+		if child.kind  != .Element                { continue }
+
+		/*
+			If the ident matches and it's the nth such child, return it.
+		*/
+		if child.ident == ident {
+			if count == nth                       { return child, true }
+			count += 1
+		}
+	}
+	return nil, false
+}
+
+/*
+	Find an attribute by key.
+*/
+find_attribute_val_by_key :: proc(tag: ^Element, key: string) -> (val: string, found: bool) {
+	if tag == nil            { return "", false }
+
+	for attr in tag.attribs {
+		/*
+			If the ident matches, we're done. There can only ever be one attribute with the same name.
+		*/
+		if attr.key == key { return attr.val, true }
+	}
+	return "", false
+}