clang-format: [JS] simplify import/export.

Summary:
Change `import` and `export` parsing to special case the renaming
syntax (`import x, {y as bar} ...`, `export {x}`) and otherwise just
parse a regular structural element.

This simplifies the code a bit and should be more correct - it's easier
to recognise the specific import syntax than to recognise arbitrary
expressions and declarations.

Reviewers: djasper

Subscribers: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D19242

llvm-svn: 266743

2 files changed, 13 insertions, 9 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 6cd74f91a8a..91856a74c35 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1880,7 +1880,8 @@ void UnwrappedLineParser::parseObjCProtocol() {
 }
 
 void UnwrappedLineParser::parseJavaScriptEs6ImportExport() {
-  assert(FormatTok->isOneOf(Keywords.kw_import, tok::kw_export));
+  bool IsImport = FormatTok->is(Keywords.kw_import);
+  assert(IsImport || FormatTok->is(tok::kw_export));
   nextToken();
 
   // Consume the "default" in "export default class/function".
@@ -1894,14 +1895,13 @@ void UnwrappedLineParser::parseJavaScriptEs6ImportExport() {
     return;
   }
 
-  // Consume the "abstract" in "export abstract class".
-  if (FormatTok->is(Keywords.kw_abstract))
-    nextToken();
-
-  if (FormatTok->isOneOf(tok::kw_const, tok::kw_class, tok::kw_enum,
-                         Keywords.kw_interface, Keywords.kw_let,
-                         Keywords.kw_var))
-    return; // Fall through to parsing the corresponding structure.
+  // For imports, `export *`, `export {...}`, consume the rest of the line up
+  // to the terminating `;`. For everything else, just return and continue
+  // parsing the structural element, i.e. the declaration or expression for
+  // `export default`.
+  if (!IsImport && !FormatTok->isOneOf(tok::l_brace, tok::star) &&
+      !FormatTok->isStringLiteral())
+    return;
 
   while (!eof() && FormatTok->isNot(tok::semi)) {
     if (FormatTok->is(tok::l_brace)) {
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 5fa91e986a8..a3cb6016d64 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -961,6 +961,10 @@ TEST_F(FormatTestJS, Modules) {
   verifyFormat("export function A() {}\n"
                "export default function B() {}\n"
                "export function C() {}");
+  verifyFormat("export default () => {\n"
+               "  let x = 1;\n"
+               "  return x;\n"
+               "}");
   verifyFormat("export const x = 12;");
   verifyFormat("export default class X {}");
   verifyFormat("export {X, Y} from 'some/module.js';");