feat: remove unnecessary parens

src/pretty/code_list.rs

@@ -2,7 +2,7 @@ use typst_syntax::{ast::*, SyntaxKind};
 
 use super::{
     list::{ListStyle, ListStylist},
-    util::is_only_one_and,
+    util::{has_comment_children, is_only_one_and},
     ArenaDoc, PrettyPrinter,
 };
 
@@ -11,6 +11,20 @@ impl<'a> PrettyPrinter<'a> {
         &'a self,
         parenthesized: Parenthesized<'a>,
     ) -> ArenaDoc<'a> {
+        // NOTE: This is a safe cast. The parentheses for patterns are all optional.
+        let expr = parenthesized.expr();
+        let can_omit = (expr.is_literal()
+            || matches!(
+                expr.to_untyped().kind(),
+                SyntaxKind::Ident
+                    | SyntaxKind::Array
+                    | SyntaxKind::Dict
+                    | SyntaxKind::Destructuring
+                    | SyntaxKind::CodeBlock
+                    | SyntaxKind::ContentBlock
+            ))
+            && !has_comment_children(parenthesized.to_untyped());
+
         ListStylist::new(self)
             .process_list(parenthesized.to_untyped(), |node| {
                 self.convert_pattern(node)
@@ -21,7 +35,7 @@ impl<'a> PrettyPrinter<'a> {
                 add_space_if_empty: false,
                 add_trailing_sep_single: false,
                 omit_delim_single: false,
-                omit_delim_flat: false,
+                omit_delim_flat: can_omit,
             })
     }
 
@@ -65,7 +79,9 @@ impl<'a> PrettyPrinter<'a> {
             .process_list(destructuring.to_untyped(), |node| {
                 self.convert_destructuring_item(node)
             })
-            .always_fold_if(|| only_one_pattern)
+            .always_fold_if(|| {
+                only_one_pattern && !has_comment_children(destructuring.to_untyped())
+            })
             .print_doc(ListStyle {
                 separator: ",",
                 delim: ("(", ")"),
@@ -87,7 +103,7 @@ impl<'a> PrettyPrinter<'a> {
 
         ListStylist::new(self)
             .process_list(params.to_untyped(), |node| self.convert_param(node))
-            .always_fold_if(|| is_single_simple)
+            .always_fold_if(|| is_single_simple && !has_comment_children(params.to_untyped()))
             .print_doc(ListStyle {
                 separator: ",",
                 delim: ("(", ")"),

src/pretty/list.rs

@@ -243,7 +243,7 @@ impl<'a> ListStylist<'a> {
                     }
                 }
                 if is_single && sty.omit_delim_single {
-                    inner
+                    inner.group()
                 } else {
                     inner = (arena.line_() + inner).nest(2);
                     if sty.omit_delim_flat {

src/pretty/parened_expr.rs

@@ -3,7 +3,7 @@ use typst_syntax::ast::*;
 
 use crate::PrettyPrinter;
 
-use super::{util::is_comment_node, ArenaDoc};
+use super::{util::has_comment_children, ArenaDoc};
 
 impl<'a> PrettyPrinter<'a> {
     /// We do not care whether it is `Pattern` or `Expr`.
@@ -14,7 +14,7 @@ impl<'a> PrettyPrinter<'a> {
     ) -> ArenaDoc<'a> {
         let pattern = parenthesized.pattern();
         if let Pattern::Parenthesized(paren) = pattern {
-            if !parenthesized.to_untyped().children().any(is_comment_node) {
+            if !has_comment_children(parenthesized.to_untyped()) {
                 // Remove a layer of paren if no comment inside.
                 return self.convert_parenthesized(paren);
             }

src/pretty/util.rs

@@ -17,6 +17,10 @@ pub fn is_comment_node(node: &SyntaxNode) -> bool {
     )
 }
 
+pub fn has_comment_children(node: &SyntaxNode) -> bool {
+    node.children().any(is_comment_node)
+}
+
 pub(super) fn indent_func_name(node: FuncCall<'_>) -> Option<&str> {
     node.callee()
         .to_untyped()

tests/assets/unit/code/extra-paren.typ

@@ -55,3 +55,7 @@
 
 #let  (( (( ((a)),))) ) =((( ( (1)),)) )
 #let  (((( (( (a)),)) ))) =((((( (1)),)) ))
+
+#let a = ((b:((c : ((3))))))
+#let a = ({(true)})
+#let a = (([()]))

tests/snapshots/assets__check_file@cetz-manual.typ-120.snap

@@ -817,7 +817,7 @@ plot.plot(
 ===== Keys
 #doc-style.show-parameter-block(
   "orientation",
-  ("direction"),
+  "direction",
   default: ttb,
   [
     The direction the legend items get laid out to.
@@ -833,79 +833,79 @@ plot.plot(
 )
 #doc-style.show-parameter-block(
   "layer",
-  ("number"),
+  "number",
   default: 1,
   [
     The layer index the legend gets drawn at, see on-layer.
   ],
 )
 #doc-style.show-parameter-block(
   "fill",
-  ("paint"),
+  "paint",
   default: rgb(255, 255, 255, 200),
   [
     The legends frame background color.
   ],
 )
 #doc-style.show-parameter-block(
   "stroke",
-  ("stroke"),
+  "stroke",
   default: black,
   [
     The legends frame stroke style.
   ],
 )
 #doc-style.show-parameter-block(
   "padding",
-  ("float"),
+  "float",
   default: .1,
   [
     The legends frame padding, that is the distance added between its items and its frame.
   ],
 )
 #doc-style.show-parameter-block(
   "offset",
-  ("tuple"),
+  "tuple",
   default: (0, 0),
   [
     An offset tuple (x and y coordinates) to add to the legends position.
   ],
 )
 #doc-style.show-parameter-block(
   "spacing",
-  ("number"),
+  "number",
   default: .1,
   [
     The spacing between the legend position and its frame.
   ],
 )
 #doc-style.show-parameter-block(
   "item.spacing",
-  ("number"),
+  "number",
   default: .05,
   [
     The spacing between two legend items in canvas units.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.width",
-  ("number"),
+  "number",
   default: .75,
   [
     The width of a legend items preview picture, a small preview of the graph the legend item belongs to.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.height",
-  ("number"),
+  "number",
   default: .3,
   [
     The height of a legend items preview picture.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.margin",
-  ("number"),
+  "number",
   default: .1,
   [
     Margin between the preview picture and the item label.

tests/snapshots/assets__check_file@cetz-manual.typ-40.snap

@@ -2,6 +2,7 @@
 source: tests/assets.rs
 expression: doc_string
 input_file: tests/assets/cetz-manual.typ
+snapshot_kind: text
 ---
 #import "doc/util.typ": *
 #import "doc/example.typ": example
@@ -921,7 +922,7 @@ plot.plot(
 ===== Keys
 #doc-style.show-parameter-block(
   "orientation",
-  ("direction"),
+  "direction",
   default: ttb,
   [
     The direction the legend items get laid out to.
@@ -937,79 +938,79 @@ plot.plot(
 )
 #doc-style.show-parameter-block(
   "layer",
-  ("number"),
+  "number",
   default: 1,
   [
     The layer index the legend gets drawn at, see on-layer.
   ],
 )
 #doc-style.show-parameter-block(
   "fill",
-  ("paint"),
+  "paint",
   default: rgb(255, 255, 255, 200),
   [
     The legends frame background color.
   ],
 )
 #doc-style.show-parameter-block(
   "stroke",
-  ("stroke"),
+  "stroke",
   default: black,
   [
     The legends frame stroke style.
   ],
 )
 #doc-style.show-parameter-block(
   "padding",
-  ("float"),
+  "float",
   default: .1,
   [
     The legends frame padding, that is the distance added between its items and its frame.
   ],
 )
 #doc-style.show-parameter-block(
   "offset",
-  ("tuple"),
+  "tuple",
   default: (0, 0),
   [
     An offset tuple (x and y coordinates) to add to the legends position.
   ],
 )
 #doc-style.show-parameter-block(
   "spacing",
-  ("number"),
+  "number",
   default: .1,
   [
     The spacing between the legend position and its frame.
   ],
 )
 #doc-style.show-parameter-block(
   "item.spacing",
-  ("number"),
+  "number",
   default: .05,
   [
     The spacing between two legend items in canvas units.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.width",
-  ("number"),
+  "number",
   default: .75,
   [
     The width of a legend items preview picture, a small preview of the graph the legend item belongs to.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.height",
-  ("number"),
+  "number",
   default: .3,
   [
     The height of a legend items preview picture.
   ],
 )
 #doc-style.show-parameter-block(
   "item.preview.margin",
-  ("number"),
+  "number",
   default: .1,
   [
     Margin between the preview picture and the item label.