Commit 11a4ce42c1

LemonBoy <thatlemon@gmail.com>
2020-02-28 12:06:43
zig fmt: Respect trailing commas in error set declarations
The logic is not perfect as it doesn't take into account the presence of doc comments, but it's an improvement over the status quo.
master
1 parent 63a4dbc
Changed files (2)
lib
std
zig
parser_test.zig
render.zig
lib/std/zig/parser_test.zig
@@ -1509,6 +1509,8 @@ test "zig fmt: error set declaration" {
         \\const Error = error{OutOfMemory};
         \\const Error = error{};
         \\
+        \\const Error = error{ OutOfMemory, OutOfTime };
+        \\
     );
 }
lib/std/zig/render.zig
@@ -1268,25 +1268,51 @@ fn renderExpression(
             }
 
             try renderToken(tree, stream, err_set_decl.error_token, indent, start_col, Space.None); // error
-            try renderToken(tree, stream, lbrace, indent, start_col, Space.Newline); // {
-            const new_indent = indent + indent_delta;
 
-            var it = err_set_decl.decls.iterator(0);
-            while (it.next()) |node| {
-                try stream.writeByteNTimes(' ', new_indent);
+            const src_has_trailing_comma = blk: {
+                const maybe_comma = tree.prevToken(err_set_decl.rbrace_token);
+                break :blk tree.tokens.at(maybe_comma).id == .Comma;
+            };
 
-                if (it.peek()) |next_node| {
-                    try renderExpression(allocator, stream, tree, new_indent, start_col, node.*, Space.None);
-                    try renderToken(tree, stream, tree.nextToken(node.*.lastToken()), new_indent, start_col, Space.Newline); // ,
+            if (src_has_trailing_comma) {
+                try renderToken(tree, stream, lbrace, indent, start_col, Space.Newline); // {
+                const new_indent = indent + indent_delta;
 
-                    try renderExtraNewline(tree, stream, start_col, next_node.*);
-                } else {
-                    try renderExpression(allocator, stream, tree, new_indent, start_col, node.*, Space.Comma);
+                var it = err_set_decl.decls.iterator(0);
+                while (it.next()) |node| {
+                    try stream.writeByteNTimes(' ', new_indent);
+
+                    if (it.peek()) |next_node| {
+                        try renderExpression(allocator, stream, tree, new_indent, start_col, node.*, Space.None);
+                        try renderToken(tree, stream, tree.nextToken(node.*.lastToken()), new_indent, start_col, Space.Newline); // ,
+
+                        try renderExtraNewline(tree, stream, start_col, next_node.*);
+                    } else {
+                        try renderExpression(allocator, stream, tree, new_indent, start_col, node.*, Space.Comma);
+                    }
                 }
-            }
 
-            try stream.writeByteNTimes(' ', indent);
-            return renderToken(tree, stream, err_set_decl.rbrace_token, indent, start_col, space); // }
+                try stream.writeByteNTimes(' ', indent);
+                return renderToken(tree, stream, err_set_decl.rbrace_token, indent, start_col, space); // }
+            } else {
+                try renderToken(tree, stream, lbrace, indent, start_col, Space.Space); // {
+
+                var it = err_set_decl.decls.iterator(0);
+                while (it.next()) |node| {
+                    if (it.peek()) |next_node| {
+                        try renderExpression(allocator, stream, tree, indent, start_col, node.*, Space.None);
+
+                        const comma_token = tree.nextToken(node.*.lastToken());
+                        assert(tree.tokens.at(comma_token).id == .Comma);
+                        try renderToken(tree, stream, comma_token, indent, start_col, Space.Space); // ,
+                        try renderExtraNewline(tree, stream, start_col, next_node.*);
+                    } else {
+                        try renderExpression(allocator, stream, tree, indent, start_col, node.*, Space.Space);
+                    }
+                }
+
+                return renderToken(tree, stream, err_set_decl.rbrace_token, indent, start_col, space); // }
+            }
         },
 
         .ErrorTag => {
@@ -1589,8 +1615,7 @@ fn renderExpression(
                 }
             } else {
                 var it = switch_case.items.iterator(0);
-                while (true) {
-                    const node = it.next().?;
+                while (it.next()) |node| {
                     if (it.peek()) |next_node| {
                         try renderExpression(allocator, stream, tree, indent, start_col, node.*, Space.None);
 
@@ -1601,7 +1626,6 @@ fn renderExpression(
                     } else {
                         try renderExpression(allocator, stream, tree, indent, start_col, node.*, Space.Comma);
                         try stream.writeByteNTimes(' ', indent);
-                        break;
                     }
                 }
             }