feat: improve parentheses handling

src/alejandra_engine/src/rules/paren.rs

@@ -10,17 +10,16 @@ pub(crate) fn rule(
     let expression = children.next().unwrap();
     let closer = children.next().unwrap();
 
-    let vertical = opener.has_inline_comment
+    let loose = opener.has_inline_comment
         || opener.has_comments
         || expression.has_inline_comment
         || expression.has_comments
         || closer.has_inline_comment
         || closer.has_comments
+        || matches!(expression.element.kind(), rnix::SyntaxKind::NODE_IF_ELSE);
+
+    let should_indent = loose
         || matches!(
-            expression.element.kind(),
-            rnix::SyntaxKind::NODE_IF_ELSE | rnix::SyntaxKind::NODE_LET_IN
-        )
-        || (matches!(
             expression.element.kind(),
             rnix::SyntaxKind::NODE_APPLY
                 | rnix::SyntaxKind::NODE_ASSERT
@@ -32,11 +31,11 @@ pub(crate) fn rule(
         ) && second_through_penultimate_line_are_not_indented(
             build_ctx,
             expression.element.clone(),
-        ));
+        );
 
     // opener
     steps.push_back(crate::builder::Step::Format(opener.element));
-    if vertical {
+    if should_indent {
         steps.push_back(crate::builder::Step::Indent);
     }
 
@@ -45,7 +44,7 @@ pub(crate) fn rule(
         steps.push_back(crate::builder::Step::Comment(text));
         steps.push_back(crate::builder::Step::NewLine);
         steps.push_back(crate::builder::Step::Pad);
-    } else if vertical {
+    } else if loose {
         steps.push_back(crate::builder::Step::NewLine);
         steps.push_back(crate::builder::Step::Pad);
     }
@@ -62,7 +61,7 @@ pub(crate) fn rule(
     }
 
     // expression
-    if vertical {
+    if loose {
         steps.push_back(crate::builder::Step::FormatWider(expression.element));
     } else {
         steps.push_back(crate::builder::Step::Format(expression.element));
@@ -85,8 +84,11 @@ pub(crate) fn rule(
     }
 
     // closer
-    if vertical {
+    if should_indent {
         steps.push_back(crate::builder::Step::Dedent);
+    }
+
+    if loose {
         steps.push_back(crate::builder::Step::NewLine);
         steps.push_back(crate::builder::Step::Pad);
     }
@@ -111,12 +113,14 @@ fn second_through_penultimate_line_are_not_indented(
         return false;
     }
 
-    let whitespace = format!("{0:<1$}", "", 2 * (build_ctx.indentation + 1));
+    let whitespace = format!("{0:<1$}  ", "", 2 * build_ctx.indentation);
+    let lambda = format!("{0:<1$}}}:", "", 2 * build_ctx.indentation);
+    let in_ = format!("{0:<1$}in", "", 2 * build_ctx.indentation);
 
-    formatted_lines
+    formatted_lines.iter().skip(1).rev().skip(1).any(|line| {
-        .iter()
+        !line.is_empty()
-        .skip(1)
+            && !(line.starts_with(&whitespace)
-        .rev()
+                || line.starts_with(&lambda)
-        .skip(1)
+                || line.starts_with(&in_))
-        .any(|line| !line.is_empty() && !line.starts_with(&whitespace))
+    })
 }

src/alejandra_engine/tests/cases/apply/out

@@ -1,12 +1,10 @@
 (a b)
 (a b)
-(
+(a
-  a
   /*
    b
    */
-  c
+  c)
-)
 (
   /*
    a

src/alejandra_engine/tests/cases/assert/out

@@ -1,29 +1,22 @@
 [
   (assert b; e)
-  (
+  (assert b;
-    assert b;
     /*
      d
      */
-      e
+      e)
-  )
   (assert b; e)
-  (
+  (assert b;
-    assert b;
     /*
      d
      */
-      e
+      e)
-  )
+  (assert
-  (
-    assert
     /*
      a
      */
-    b; e
+    b; e)
-  )
+  (assert
-  (
-    assert
     /*
      a
      */
@@ -31,17 +24,13 @@
     /*
      d
      */
-      e
+      e)
-  )
+  (assert
-  (
-    assert
     /*
      a
      */
-    b; e
+    b; e)
-  )
+  (assert
-  (
-    assert
     /*
      a
      */
@@ -49,8 +38,7 @@
     /*
      d
      */
-      e
+      e)
-  )
   (assert b; cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc)
   (assert b; cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc)
 ]

src/alejandra_engine/tests/cases/bin_op/out

@@ -1,45 +1,32 @@
 [
   (1 + 1)
-  (
+  (1
-    1
     +
     /**/
-    1
+    1)
-  )
+  (1
-  (
-    1
     /**/
-    + 1
+    + 1)
-  )
+  (1
-  (
-    1
     /**/
     +
     /**/
-    1
+    1)
-  )
+  (1
-  (
-    1
     /**/
     +
     /**/
-    (
+    (1
-      1
       /**/
       +
       /**/
-      (
+      (1
-        1
         /**/
         +
         /**/
-        1
+        1)))
-      )
-    )
-  )
   (1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1)
-  (
+  (1
-    1
     + 1
     + 1
     + 1
@@ -58,6 +45,5 @@
     + 1
     + 1
     + 1
-    + 1
+    + 1)
-  )
 ]

src/alejandra_engine/tests/cases/comment/out

@@ -81,28 +81,24 @@
     #7
   }
 
-  (
+  (let
-    let
+    # 1
-      # 1
+    #2
-      #2
+    a = 1; # 3
-      a = 1; # 3
+    b = 1;
-      b = 1;
+    c = 1; # 4
-      c = 1; # 4
+    #5
-      #5
 
-      #6
+    #6
 
-      d = 1;
+    d = 1;
-      #7
+    #7
-    in
+  in
-      d
+    d)
-  )
 
-  (
+  ({
-    {
+    a, # comment
-      a, # comment
+    b ? 2, # comment
-      b ? 2, # comment
+  }:
-    }:
+    _)
-      _
-  )
 ]

src/alejandra_engine/tests/cases/lambda/out

@@ -1,43 +1,32 @@
 [
-  (
+  (a: b:
-    a: b:
     /*
      c
      */
-      d
+      d)
-  )
+  ({}: b:
-  (
-    {}: b:
     /*
      c
      */
-      d
+      d)
-  )
+  (a: {}:
-  (
-    a: {}:
     /*
      c
      */
-      d
+      d)
-  )
   (a: d)
-  (
+  (a:
-    a:
     /*
      c
      */
-      d
+      d)
-  )
+  (a
-  (
-    a
     /*
      b
      */
     :
-      d
+      d)
-  )
+  (a
-  (
-    a
     /*
      b
      */
@@ -45,17 +34,14 @@
     /*
      c
      */
-      d
+      d)
-  )
   (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
   (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
-  (
+  ({
-    {
+    pkgs ? import ./.. {},
-      pkgs ? import ./.. {},
+    locationsXml,
-      locationsXml,
+  }:
-    }:
+    null)
-      null
-  )
   (a: b: c: {}: a: b: c:
     a)
 
@@ -63,23 +49,19 @@
     # Stuff
   })
 
-  (
+  ({pkgs, ...}: let
-    {pkgs, ...}: let
+  in
-    in
+    pkgs)
-      pkgs
-  )
 
   (a: {b, ...}: c: {
     # Stuff
   })
 
-  (
+  (a: {
-    a: {
+    b,
-      b,
+    c,
-      c,
+    ...
-      ...
+  }: d: {
-    }: d: {
+    # Stuff
-      # Stuff
+  })
-    }
-  )
 ]

src/alejandra_engine/tests/cases/or_default/out

@@ -1,68 +1,48 @@
 [
   (a.b or c)
-  (
+  (a.b
-    a.b
     or
     /**/
-    c
+    c)
-  )
+  (a.b
-  (
-    a.b
     /**/
-    or c
+    or c)
-  )
+  (a.b
-  (
-    a.b
     /**/
     or
     /**/
-    c
+    c)
-  )
+  (a.b
-  (
-    a.b
     /**/
     or
     /**/
-    (
+    (a.b
-      a.b
       /**/
       or
       /**/
-      (
+      (a.b
-        a.b
         /**/
         or
         /**/
-        c
+        c)))
-      )
+  (a.b
-    )
-  )
-  (
-    a.b
     /**/
     or
     /**/
-    (
+    (a.b
-      a.b
       /**/
       or
       /**/
-      (
+      (a.b
-        a.b
         /**/
         or
         /**/
-        c
+        c)))
-      )
-    )
-  )
   (a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a)
-  (
+  (a.a
-    a.a
     or a.a # test
     or a.a # test
     or # test
     a.a
-    or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a
+    or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a or a.a)
-  )
 ]

src/alejandra_engine/tests/cases/paren/out

@@ -1,5 +1,4 @@
-(
+(( # test
-  ( # test
     a # test
   )
   c
@@ -161,5 +160,4 @@
     /*
      e
      */
-  )
+  ))
-)

src/alejandra_engine/tests/cases/pat_bind/out

@@ -1,45 +1,33 @@
 [
   ({} @ a: _)
-  (
+  ({} @
-    {} @
     /**/
     a:
-      _
+      _)
-  )
+  ({}
-  (
-    {}
     /**/
     @ a:
-      _
+      _)
-  )
+  ({}
-  (
-    {}
     /**/
     @
     /**/
     a:
-      _
+      _)
-  )
 
   (a @ {}: _)
-  (
+  (a @
-    a @
     /**/
     {}:
-      _
+      _)
-  )
+  (a
-  (
-    a
     /**/
     @ {}:
-      _
+      _)
-  )
+  (a
-  (
-    a
     /**/
     @
     /**/
     {}:
-      _
+      _)
-  )
 ]

src/alejandra_engine/tests/cases/select/out

@@ -1,26 +1,19 @@
 [
   (a.a)
-  (
+  (a
-    a
     .
     /**/
-    a
+    a)
-  )
+  (a
-  (
-    a
     /**/
-    .a
+    .a)
-  )
+  (a
-  (
-    a
     /**/
     .
     /**/
-    a
+    a)
-  )
   (a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a)
-  (
+  (a
-    a
     .a
     .a
     .a
@@ -58,6 +51,5 @@
     .a
     .a
     .a
-    .a
+    .a)
-  )
 ]

src/alejandra_engine/tests/cases/with/out

@@ -1,21 +1,16 @@
 [
   (with b; c)
-  (
+  (with b;
-    with b;
     /*
      b
      */
-      c
+      c)
-  )
+  (with
-  (
-    with
     /*
      a
      */
-    b; c
+    b; c)
-  )
+  (with
-  (
-    with
     /*
      a
      */
@@ -23,8 +18,7 @@
     /*
      b
      */
-      c
+      c)
-  )
   (with b; cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc)
   (with b; cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc)
   {a = with b; 1;}
@@ -47,16 +41,13 @@
     # comment
   }
   (with a; with b; with c; {a = 1;})
-  (
+  (with a;
-    with a;
     with b;
     with c; {
       a = 1;
       b = 2;
-    }
+    })
-  )
+  (with a;
-  (
-    with a;
     /*
      comment
      */
@@ -64,8 +55,7 @@
     with c; {
       a = 1;
       b = 2;
-    }
+    })
-  )
   {
     a = with b; with b; with b; 1;
   }