Rework grammar compactions

Let's fix up the grammar compactions to follow the indentation and
spacing style we use for this grammar (especially as the indentation
is preserved into the rendering), remove superfluous parentheses, and
add line breaks in alternations and elsewhere to add clarity.

Author: traviscross

src/attributes.md

@@ -116,7 +116,10 @@ attributes]. It has the following grammar:
 r[attributes.meta.syntax]
 ```grammar,attributes
 MetaItem ->
-      SimplePath ((`=` Expression) | (`(` MetaSeq? `)`))?
+    SimplePath (
+        `=` Expression
+      | `(` MetaSeq? `)`
+    )?
 
 MetaSeq ->
     MetaItemInner ( `,` MetaItemInner )* `,`?

src/expressions/array-expr.md

@@ -8,7 +8,10 @@ r[expr.array.syntax]
 ArrayExpression -> `[` ArrayElements? `]`
 
 ArrayElements ->
-      Expression (( `,` Expression )* `,`? | (`;` Expression ))
+    Expression (
+        ( `,` Expression )* `,`?
+      | `;` Expression
+    )
 ```
 
 r[expr.array.constructor]

src/expressions/block-expr.md

@@ -10,7 +10,7 @@ BlockExpression ->
     `}`
 
 Statements ->
-    Statement+ ExpressionWithoutBlock?
+      Statement+ ExpressionWithoutBlock?
     | ExpressionWithoutBlock
 ```
 

src/expressions/operator-expr.md

@@ -58,7 +58,9 @@ r[expr.operator.borrow]
 r[expr.operator.borrow.syntax]
 ```grammar,expressions
 BorrowExpression ->
-    (`&`|`&&`) ( `mut` | (`raw` (`const` | `mut`)))? Expression
+    ( `&` | `&&` )
+    ( `mut` | `raw` ( `const` | `mut` ) )?
+    Expression
 ```
 
 r[expr.operator.borrow.intro]
@@ -288,7 +290,9 @@ r[expr.arith-logic]
 r[expr.arith-logic.syntax]
 ```grammar,expressions
 ArithmeticOrLogicalExpression ->
-      Expression ( `+` | `-` | `*` | `/` | `%` | `&` | `|` | `^` | `<<` | `>>` ) Expression
+    Expression (
+        `+` | `-` | `*` | `/` | `%` | `&` | `|` | `^` | `<<` | `>>`
+    ) Expression
 ```
 
 r[expr.arith-logic.intro]
@@ -342,7 +346,9 @@ r[expr.cmp]
 r[expr.cmp.syntax]
 ```grammar,expressions
 ComparisonExpression ->
-      Expression ( `==` | `!=` | `>` | `<` | `>=` | `<=` ) Expression
+    Expression (
+        `==` | `!=` | `>` | `<` | `>=` | `<=`
+    ) Expression
 ```
 
 r[expr.cmp.intro]
@@ -396,7 +402,7 @@ r[expr.bool-logic]
 r[expr.bool-logic.syntax]
 ```grammar,expressions
 LazyBooleanExpression ->
-      Expression (`||` | `&&`) Expression
+    Expression (`||` | `&&`) Expression
 ```
 
 r[expr.bool-logic.intro]
@@ -791,7 +797,11 @@ r[expr.compound-assign]
 r[expr.compound-assign.syntax]
 ```grammar,expressions
 CompoundAssignmentExpression ->
-      Expression (`+=` | `-=` | `*=` | `/=` | `%=` | `&=` | `|=` | `^=` | `<<=` | `>>=`) Expression
+    Expression (
+        `+=` | `-=` | `*=` | `/=` | `%=`
+      | `&=` | `|=` | `^=`
+      | `<<=` | `>>=`
+    ) Expression
 ```
 
 r[expr.compound-assign.intro]

src/inline-assembly.md

@@ -73,20 +73,21 @@ AsmOption ->
     | `att_syntax`
     | `raw`
 
-RegOperand -> (ParamName `=`)?
-    (
-          ((DirSpec `(` RegSpec `)`)
-           | `const`
-          ) Expression
-        | DualDirSpec `(` RegSpec `)` DualDirSpecExpression
-        | `sym` PathExpression
-        | `label` `{` Statements? `}`
+RegOperand ->
+    (ParamName `=`)? (
+        (
+            DirSpec `(` RegSpec `)`
+          | `const`
+        ) Expression
+      | DualDirSpec `(` RegSpec `)` DualDirSpecExpression
+      | `sym` PathExpression
+      | `label` `{` Statements? `}`
     )
 
 ParamName -> IDENTIFIER_OR_KEYWORD | RAW_IDENTIFIER
 
 DualDirSpecExpression ->
-    Expression (`=>` Expression)?
+    Expression ( `=>` Expression )?
 
 RegSpec -> RegisterClass | ExplicitRegister
 

src/items/external-blocks.md

@@ -11,8 +11,8 @@ ExternBlock ->
 
 ExternalItem ->
     OuterAttribute* (
-      Visibility? (StaticItem | Function)
-      |  MacroInvocationSemi
+        Visibility? ( StaticItem | Function )
+      | MacroInvocationSemi
     )
 ```
 

src/items/functions.md

@@ -21,7 +21,7 @@ FunctionParameters ->
 
 SelfParam -> OuterAttribute* ( ShorthandSelf | TypedSelf )
 
-ShorthandSelf -> (`&` Lifetime?)? `mut`? `self`
+ShorthandSelf -> ( `&` Lifetime? )? `mut`? `self`
 
 TypedSelf -> `mut`? `self` `:` Type
 

src/items/modules.md

@@ -4,7 +4,10 @@ r[items.mod]
 r[items.mod.syntax]
 ```grammar,items
 Module ->
-      `unsafe`? `mod` IDENTIFIER ( `;` | (`{` InnerAttribute* Item* `}` ))
+    `unsafe`? `mod` IDENTIFIER (
+        `{` InnerAttribute* Item* `}`
+      | `;`
+    )
 ```
 
 r[items.mod.intro]

src/items/use-declarations.md

@@ -6,7 +6,10 @@ r[items.use.syntax]
 UseDeclaration -> `use` UseTree `;`
 
 UseTree ->
-      (SimplePath? `::`)? (`*` | (`{` (UseTree ( `,`  UseTree )* `,`?)? `}`))
+      ( SimplePath? `::` )? (
+          `{` ( UseTree ( `,`  UseTree )* `,`? )? `}`
+        | `*`
+      )
     | SimplePath ( `as` ( IDENTIFIER | `_` ) )?
 ```
 

src/macros-by-example.md

@@ -7,10 +7,11 @@ MacroRulesDefinition ->
     `macro_rules` `!` IDENTIFIER MacroRulesDef
 
 MacroRulesDef ->
-      (  (`(` MacroRules `)`)
-       | (`[` MacroRules `]`)
-      )`;`
-    |    (`{` MacroRules `}`)
+      (
+          `(` MacroRules `)`
+        | `[` MacroRules `]`
+      ) `;`
+    | `{` MacroRules `}`
 
 MacroRules ->
     MacroRule ( `;` MacroRule )* `;`?
@@ -26,8 +27,11 @@ MacroMatcher ->
 MacroMatch ->
       Token _except `$` and [delimiters][lex.token.delim]_
     | MacroMatcher
-    | `$` ((( IDENTIFIER_OR_KEYWORD _except `crate`_ | RAW_IDENTIFIER | `_` ) `:` MacroFragSpec)
-           | (`(` MacroMatch+ `)` MacroRepSep? MacroRepOp))
+    | `$` (
+          ( IDENTIFIER_OR_KEYWORD _except `crate`_ | RAW_IDENTIFIER | `_` )
+          `:` MacroFragSpec
+        | `(` MacroMatch+ `)` MacroRepSep? MacroRepOp
+      )
 
 MacroFragSpec ->
       `block` | `expr` | `expr_2021` | `ident` | `item` | `lifetime` | `literal`