add anchor

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   * Meta (`meta`, `title`)
   * Text (`h1` to `h6`, and `text`)
   * Container (`div`)
+  * Anchor (`a`) and related attributes (`href`, `download`)
   * Escape hatches (`raw` and `raw_unsafe`)
 * implement `From<(&'static str, Cow<'static, str)>` for `Attribute`
 * implement `From<&'static str>` and `From<String>` for `Element`

src/attributes.rs

@@ -16,6 +16,14 @@ pub fn id(id: impl Into<Cow<'static, str>>) -> Attribute {
     Attribute::new("id", id)
 }
 
+pub fn href(url: impl Into<Cow<'static, str>>) -> Attribute {
+    Attribute::new("href", url)
+}
+
+pub fn download() -> Attribute {
+    Attribute::new_flag("download")
+}
+
 pub fn class<'a>(classes: impl IntoIterator<Item = &'a str>) -> Attribute {
     let mut values = String::new();
     let mut iter = classes.into_iter();

src/elements.rs

@@ -76,6 +76,13 @@ pub fn h6(
     Element::new("h6", attributes, children)
 }
 
+pub fn a(
+    attributes: impl IntoIterator<Item = Attribute>,
+    children: impl IntoIterator<Item = Element>,
+) -> Element {
+    Element::new("a", attributes, children)
+}
+
 /// HTML escaped text
 pub fn text(value: impl Into<Cow<'static, str>>) -> Element {
     ElementInner::Text(value.into()).into()

src/lib.rs

@@ -44,6 +44,7 @@ pub struct Attribute {
 #[derive(Debug, Clone)]
 enum AttributeValue {
     String(Cow<'static, str>),
+    Flag,
 }
 
 impl Default for Document {
@@ -147,22 +148,35 @@ fn write_attributes(
                 attribute.name,
                 html_escape::encode_double_quoted_attribute(s)
             )?,
+            AttributeValue::Flag => write!(f, " {}", attribute.name,)?,
         }
     }
     Ok(())
 }
 
 impl Attribute {
     pub fn new(name: &'static str, value: impl Into<Cow<'static, str>>) -> Self {
-        debug_assert!(
-            !name.is_empty() && name.chars().all(|c| !c.is_whitespace()),
-            "invalid attribute name: '{name}'"
-        );
+        assert_valid_attribute_name(name);
         Self {
             name,
             value: AttributeValue::String(value.into()),
         }
     }
+
+    pub fn new_flag(name: &'static str) -> Self {
+        assert_valid_attribute_name(name);
+        Self {
+            name,
+            value: AttributeValue::Flag,
+        }
+    }
+}
+
+fn assert_valid_attribute_name(name: &str) {
+    debug_assert!(
+        !name.is_empty() && name.chars().all(|c| !c.is_whitespace()),
+        "invalid attribute name: '{name}'"
+    );
 }
 
 pub fn html(

tests/model_spec.rs

@@ -11,6 +11,15 @@ fn should_panic_for_invalid_attribute_name(
     Attribute::new(name, "value");
 }
 
+#[rstest]
+#[cfg(debug_assertions)]
+#[should_panic]
+fn should_panic_for_invalid_attribute_flag_name(
+    #[values("hello world", "hello\tworld", "hello\nworld", "")] name: &'static str,
+) {
+    Attribute::new_flag(name);
+}
+
 #[rstest]
 #[cfg(debug_assertions)]
 #[should_panic]

tests/render_spec.rs

@@ -31,6 +31,8 @@ fn should_render_html_document() {
 #[case(id("foo"), "id=\"foo\"")]
 #[case(class(["foo"]), "class=\"foo\"")]
 #[case(class(["foo", "bar"]), "class=\"foo bar\"")]
+#[case(href("foo"), "href=\"foo\"")]
+#[case(download(), "download")]
 fn should_render_attribute(#[case] attr: Attribute, #[case] expected: &str) {
     let string = div([attr], []).to_string();
     assert_eq!(string, format!("<div {expected}></div>"));
@@ -56,6 +58,7 @@ fn should_render_attribute(#[case] attr: Attribute, #[case] expected: &str) {
 #[case(h4([id("foo")], [text("hello")]), "<h4 id=\"foo\">hello</h4>")]
 #[case(h5([id("foo")], [text("hello")]), "<h5 id=\"foo\">hello</h5>")]
 #[case(h6([id("foo")], [text("hello")]), "<h6 id=\"foo\">hello</h6>")]
+#[case(a([href("/somepath")], ["visit this cool link!".into()]), "<a href=\"/somepath\">visit this cool link!</a>")]
 fn should_render_element(#[case] def: Element, #[case] expected: &str) {
     assert_eq!(def.to_string(), expected);
 }