Support compact macros 2.0 representation

Author: RReverser

src/macros.rs

@@ -305,9 +305,16 @@ pub fn rewrite_macro_def(
 
     result += " ";
     result += &ident.name.as_str();
-    result += " {";
 
-    let mac_indent = indent.block_indent(&context.config);
+    let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
+
+    let mac_indent = if multi_branch_style {
+        result += " {";
+        indent.block_indent(&context.config)
+    } else {
+        indent
+    };
+
     let mac_indent_str = mac_indent.to_string(&context.config);
 
     for branch in parsed_def.branches {
@@ -317,11 +324,18 @@ pub fn rewrite_macro_def(
             return snippet;
         }
 
-        result += "\n";
-        result += &mac_indent_str;
-        result += "(";
-        result += &format_macro_args(branch.args)?;
-        result += ") => {\n";
+        let args = format!("({})", format_macro_args(branch.args)?);
+
+        if multi_branch_style {
+            result += "\n";
+            result += &mac_indent_str;
+            result += &args;
+            result += " =>";
+        } else {
+            result += &args;
+        }
+
+        result += " {\n";
 
         // The macro body is the most interesting part. It might end up as various
         // AST nodes, but also has special variables (e.g, `$foo`) which can't be
@@ -377,14 +391,16 @@ pub fn rewrite_macro_def(
 
         result += &mac_indent_str;
         result += "}";
-        if def.legacy{
+        if def.legacy {
             result += ";";
         }
         result += "\n";
     }
 
-    result += &indent.to_string(&context.config);
-    result += "}";
+    if multi_branch_style {
+        result += &indent.to_string(&context.config);
+        result += "}";
+    }
 
     Some(result)
 }

tests/target/macros.rs

@@ -27,9 +27,8 @@ fn main() {
     );
 
     kaas!(
-        // comments
-        a, // post macro
-        b  // another
+        /* comments */ a, /* post macro */
+        b  /* another */
     );
 
     trailingcomma!(a, b, c,);
@@ -890,28 +889,22 @@ fn macro_in_pattern_position() {
     };
 }
 
-macro foo {
-    () => {
-    }
+macro foo() {
 }
 
-pub macro bar {
-    ($x: ident + $y: expr;) => {
-        fn foo($x: Foo) {
-            long_function(
-                a_long_argument_to_a_long_function_is_what_this_is(AAAAAAAAAAAAAAAAAAAAAAAAAAAA),
-                $x.bar($y),
-            );
-        }
+pub macro bar($x: ident + $y: expr;) {
+    fn foo($x: Foo) {
+        long_function(
+            a_long_argument_to_a_long_function_is_what_this_is(AAAAAAAAAAAAAAAAAAAAAAAAAAAA),
+            $x.bar($y),
+        );
     }
 }
 
-macro foo {
-    () => {
-        // a comment
-        fn foo() {
-            // another comment
-            bar();
-        }
+macro foo() {
+    // a comment
+    fn foo() {
+        // another comment
+        bar();
     }
 }