overhauling the library, made tests pass

src/convert.rs

@@ -0,0 +1,101 @@
+//! A module which exports a few traits for converting types to elements and attributes.
+
+use element::{Element, ElementBuilder};
+
+/// A struct which is used for emitting `Element`s and text nodes into an `Element` without
+/// exposing more functionality than necessary.
+pub struct ElementEmitter<'a>(&'a mut Element);
+
+impl<'a> ElementEmitter<'a> {
+    /// Creates a new `ElementEmitter`.
+    pub fn new(root: &'a mut Element) -> ElementEmitter<'a> {
+        ElementEmitter(root)
+    }
+
+    /// Appends an `Element` to the target.
+    pub fn append_child(&mut self, element: Element) {
+        self.0.append_child(element);
+    }
+
+    /// Appends a text node to the target.
+    pub fn append_text_node(&mut self, text: String) {
+        self.0.append_text_node(text);
+    }
+}
+
+/// A trait for types which can be converted to one or multiple `Element`s.
+pub trait IntoElements {
+    /// Emits this as a sequence of text nodes and `Element`s.
+    fn into_elements(self, emitter: &mut ElementEmitter);
+}
+
+impl<T: IntoElements> IntoElements for Vec<T> {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        for elem in self {
+            elem.into_elements(emitter);
+        }
+    }
+}
+
+impl<'a, T: IntoElements + Clone> IntoElements for &'a [T] {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        self.to_vec().into_elements(emitter);
+    }
+}
+
+impl<T: IntoElements> IntoElements for Option<T> {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        match self {
+            Some(e) => e.into_elements(emitter),
+            None => (),
+        }
+    }
+}
+
+impl IntoElements for Element {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        emitter.append_child(self);
+    }
+}
+
+impl IntoElements for ElementBuilder {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        emitter.append_child(self.build());
+    }
+}
+
+impl IntoElements for String {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        emitter.append_text_node(self);
+    }
+}
+
+impl<'a> IntoElements for &'a str {
+    fn into_elements(self, emitter: &mut ElementEmitter) {
+        emitter.append_text_node(self.to_owned());
+    }
+}
+
+/// A trait for types which can be converted to an attribute value.
+pub trait IntoAttributeValue {
+    /// Turns this into an attribute string, or None if it shouldn't be added.
+    fn into_attribute_value(self) -> Option<String>;
+}
+
+impl IntoAttributeValue for String {
+    fn into_attribute_value(self) -> Option<String> {
+        Some(self.clone())
+    }
+}
+
+impl<'a> IntoAttributeValue for &'a str {
+    fn into_attribute_value(self) -> Option<String> {
+        Some((*self).to_owned())
+    }
+}
+
+impl<T: IntoAttributeValue> IntoAttributeValue for Option<T> {
+    fn into_attribute_value(self) -> Option<String> {
+        self.and_then(|t| t.into_attribute_value())
+    }
+}