Fix operator precedences, in particular |>

Fixes #571.

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Changelog
 
+## v1.0.8-alpha - unreleased
+
+### Added
+
+N/A
+
+### Fixed
+
+- Fixed operator precedences, in particular the pipe operator (`|>`) which is now of the lowest precedence.
+
+### Removed
+
+N/A
+
 ## v1.0.7-alpha - 2023-06-02
 
 ### Added

crates/aiken-lang/src/ast.rs

@@ -771,15 +771,15 @@ impl BinOp {
     pub fn precedence(&self) -> u8 {
         // Ensure that this matches the other precedence function for guards
         match self {
-            Self::Or => 1,
+            // Pipe is 0
+            // Unary operators are 1
+            Self::Or => 2,
 
-            Self::And => 2,
+            Self::And => 3,
 
-            Self::Eq | Self::NotEq => 3,
+            Self::Eq | Self::NotEq | Self::LtInt | Self::LtEqInt | Self::GtEqInt | Self::GtInt => 4,
 
-            Self::LtInt | Self::LtEqInt | Self::GtEqInt | Self::GtInt => 4,
-
-            // Pipe is 5
+            // Concatenation operators are typically 5, so we skip it.
             Self::AddInt | Self::SubInt => 6,
 
             Self::MultInt | Self::DivInt | Self::ModInt => 7,

crates/aiken-lang/src/expr.rs

@@ -651,7 +651,7 @@ impl UntypedExpr {
     pub fn binop_precedence(&self) -> u8 {
         match self {
             Self::BinOp { name, .. } => name.precedence(),
-            Self::PipeLine { .. } => 5,
+            Self::PipeLine { .. } => 0,
             _ => std::u8::MAX,
         }
     }

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

@@ -799,3 +799,20 @@ fn test_fail() {
 
     assert_fmt(src, src);
 }
+
+#[test]
+fn pipes_and_expressions() {
+    let src = indoc! {r#"
+        test fmt() {
+          (x == y) && ((z |> length()) == x)
+        }
+    "#};
+
+    let expected = indoc! {r#"
+        test fmt() {
+          x == y && ( z |> length() ) == x
+        }
+    "#};
+
+    assert_fmt(src, expected);
+}