Default enum number alignment to 'end' (#1042)

library/src/layout/enum.rs

@@ -147,6 +147,30 @@ pub struct EnumElem {
     /// If set to `{auto}`, uses the spacing [below blocks]($func/block.below).
     pub spacing: Smart<Spacing>,
 
+    /// The horizontal alignment that enum numbers should have.
+    ///
+    /// By default, this is set to `{end}`, which aligns enum numbers
+    /// towards end of the current text direction (in left-to-right script,
+    /// for example, this is the same as `{right}`). The choice of `{end}`
+    /// for horizontal alignment of enum numbers is usually preferred over
+    /// `{start}`, as numbers then grow away from the text instead of towards
+    /// it, avoiding certain visual issues. This option lets you override this
+    /// behavior, however.
+    ///
+    /// ````example
+    /// #set enum(number-align: start)
+    ///
+    /// Here are some powers of two:
+    /// 1. One
+    /// 2. Two
+    /// 4. Four
+    /// 8. Eight
+    /// 16. Sixteen
+    /// 32. Thirty two
+    /// ````
+    #[default(HorizontalAlign(GenAlign::End))]
+    pub number_align: HorizontalAlign,
+
     /// The numbered list's items.
     ///
     /// When using the enum syntax, adjacent items are automatically collected
@@ -191,6 +215,13 @@ impl Layout for EnumElem {
         let mut parents = self.parents(styles);
         let full = self.full(styles);
 
+        // Horizontally align based on the given respective parameter.
+        // Vertically align to the top to avoid inheriting 'horizon' or
+        // 'bottom' alignment from the context and having the number be
+        // displaced in relation to the item it refers to.
+        let number_align: Axes<Option<GenAlign>> =
+            Axes::new(self.number_align(styles).into(), Align::Top.into()).map(Some);
+
         for item in self.children() {
             number = item.number(styles).unwrap_or(number);
 
@@ -208,9 +239,13 @@ impl Layout for EnumElem {
                 }
             };
 
+            // Disable overhang as a workaround to end-aligned dots glitching
+            // and decreasing spacing between numbers and items.
+            let resolved =
+                resolved.aligned(number_align).styled(TextElem::set_overhang(false));
+
             cells.push(Content::empty());
-            // avoid '#set align' interference with the enum
-            cells.push(resolved.aligned(Align::LEFT_TOP.into()));
+            cells.push(resolved);
             cells.push(Content::empty());
             cells.push(item.body().styled(Self::set_parents(Parent(number))));
             number = number.saturating_add(1);

tests/typ/layout/enum-align.typ

@@ -0,0 +1,41 @@
+// Test the alignment of enum numbers.
+
+---
+// Alignment shouldn't affect number
+#set align(horizon)
+
++ ABCDEF\ GHIJKL\ MNOPQR
+   + INNER\ INNER\ INNER
++ BACK\ HERE
+
+---
+// Enum number alignment should be 'end' by default
+1. a
+10. b
+100. c
+
+#set enum(number-align: start)
+1.  a
+8.  b
+16. c
+
+---
+// Number align option should not be affected by the context
+#set align(center)
+#set enum(number-align: start)
+
+4.  c
+8.  d
+16. e\ f
+   2.  f\ g
+   32. g
+   64. h
+
+---
+// Test valid number align values (horizontal)
+#set enum(number-align: start)
+#set enum(number-align: end)
+#set enum(number-align: left)
+#set enum(number-align: right)
+// Error: 25-28 alignment must be horizontal
+#set enum(number-align: top)

tests/typ/layout/enum.typ

@@ -46,11 +46,3 @@ a + 0.
    [Second],
    enum.item(5)[Fifth]
 )
-
----
-// Alignment shouldn't affect number
-#set align(horizon)
-
-+ ABCDEF\ GHIJKL\ MNOPQR
-   + INNER\ INNER\ INNER
-+ BACK\ HERE