Correctly nest multiline pipeline expressions.

crates/aiken-lang/src/format.rs

@@ -1030,18 +1030,20 @@ impl<'comments> Formatter<'comments> {
                 _ => self.wrap_expr(expr),
             };
 
-            let expr = self.operator_side(doc, 4, expr.binop_precedence());
+            let expr = self
+                .operator_side(doc, 4, expr.binop_precedence())
+                .nest(2 * INDENT + 1);
 
             match printed_comments(comments, true) {
                 None => {
-                    let pipe = prebreak("|> ", " |> ").nest(2);
+                    let pipe = prebreak("|> ", " |> ").nest(INDENT);
                     docs.push(pipe.append(expr));
                 }
                 Some(comments) => {
                     let pipe = prebreak("|> ", "|> ");
                     docs.push(
                         " ".to_doc()
-                            .append(comments.nest(2).append(pipe.append(expr).group())),
+                            .append(comments.nest(INDENT).append(pipe.append(expr).group())),
                     );
                 }
             }

crates/aiken-lang/src/tests/format.rs

@@ -723,3 +723,28 @@ fn format_trace_callback() {
 
     assert_fmt(src, expected);
 }
+
+#[test]
+fn format_pipe_fn() {
+    let src = indoc! { r#"
+      fn foo() {
+        outputs
+          |> list.any(
+          fn(output) { value.quantity_of(output.value, policy_id, asset_name) == 1 },
+        )
+      }
+    "#};
+
+    let expected = indoc! { r#"
+      fn foo() {
+        outputs
+          |> list.any(
+               fn(output) {
+                 value.quantity_of(output.value, policy_id, asset_name) == 1
+               },
+             )
+      }
+    "#};
+
+    assert_fmt(src, expected);
+}

examples/acceptance_tests/036/validators/spend.ak

@@ -20,7 +20,7 @@ validator {
   }
 }
 
-validator (output_reference: OutputReference) {
+validator(output_reference: OutputReference) {
   fn mint(_redeemer: Void, ctx: ScriptContext) -> Bool {
     when
       list.find(

examples/acceptance_tests/078/lib/tests.ak

@@ -10,8 +10,10 @@ type DayOfTheWeek {
 
 fn is_work(day: DayOfTheWeek) {
   when day is {
-    Tuesday | Wednesday | Thursday | Friday | Saturday -> True
+    Tuesday | Wednesday | Thursday | Friday | Saturday ->
-    _ -> False
+      True
+    _ ->
+      False
   }
 }
 
@@ -25,10 +27,12 @@ test is_work_2() {
 
 fn is_happy_hour(day: DayOfTheWeek, current_time: Int) {
   when day is {
-    Monday | Sunday -> True
+    Monday | Sunday ->
+      True
     Tuesday | Wednesday | Thursday | Friday | Saturday if current_time > 18 ->
       True
-    _ -> False
+    _ ->
+      False
   }
 }