r302580 - clang-format: [JS] Don't indent JavaScript IIFEs.

[Martin Probst via cfe-commits]

Author: mprobst
Date: Tue May  9 15:04:09 2017
New Revision: 302580

URL: http://llvm.org/viewvc/llvm-project?rev=302580&view=rev
Log:
clang-format: [JS] Don't indent JavaScript IIFEs.

Because IIFEs[1] are often used like an anonymous namespace around large
sections of JavaScript code, it's useful not to indent to them (which
effectively reduces the column limit by the indent amount needlessly).

It's also common for developers to wrap these around entire files or
libraries. When adopting clang-format, changing the indent entire file
can reduce the usefulness of the blame annotations.

Patch by danbeam, thanks!

Differential Revision: https://reviews.llvm.org/D32989

Modified:
    cfe/trunk/lib/Format/UnwrappedLineParser.cpp
    cfe/trunk/unittests/Format/FormatTestJS.cpp

Modified: cfe/trunk/lib/Format/UnwrappedLineParser.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/UnwrappedLineParser.cpp?rev=302580&r1=302579&r2=302580&view=diff
==============================================================================
--- cfe/trunk/lib/Format/UnwrappedLineParser.cpp (original)
+++ cfe/trunk/lib/Format/UnwrappedLineParser.cpp Tue May  9 15:04:09 2017
@@ -476,6 +476,24 @@ static bool isGoogScope(const UnwrappedL
   return I->Tok->is(tok::l_paren);
 }
 
+static bool isIIFE(const UnwrappedLine &Line,
+                   const AdditionalKeywords &Keywords) {
+  // Look for the start of an immediately invoked anonymous function.
+  // https://en.wikipedia.org/wiki/Immediately-invoked_function_expression
+  // This is commonly done in JavaScript to create a new, anonymous scope.
+  // Example: (function() { ... })()
+  if (Line.Tokens.size() < 3)
+    return false;
+  auto I = Line.Tokens.begin();
+  if (I->Tok->isNot(tok::l_paren))
+    return false;
+  ++I;
+  if (I->Tok->isNot(Keywords.kw_function))
+    return false;
+  ++I;
+  return I->Tok->is(tok::l_paren);
+}
+
 static bool ShouldBreakBeforeBrace(const FormatStyle &Style,
                                    const FormatToken &InitialToken) {
   if (InitialToken.is(tok::kw_namespace))
@@ -493,15 +511,16 @@ void UnwrappedLineParser::parseChildBloc
   FormatTok->BlockKind = BK_Block;
   nextToken();
   {
-    bool GoogScope =
-        Style.Language == FormatStyle::LK_JavaScript && isGoogScope(*Line);
+    bool SkipIndent =
+        (Style.Language == FormatStyle::LK_JavaScript &&
+         (isGoogScope(*Line) || isIIFE(*Line, Keywords)));
     ScopedLineState LineState(*this);
     ScopedDeclarationState DeclarationState(*Line, DeclarationScopeStack,
                                             /*MustBeDeclaration=*/false);
-    Line->Level += GoogScope ? 0 : 1;
+    Line->Level += SkipIndent ? 0 : 1;
     parseLevel(/*HasOpeningBrace=*/true);
     flushComments(isOnNewLine(*FormatTok));
-    Line->Level -= GoogScope ? 0 : 1;
+    Line->Level -= SkipIndent ? 0 : 1;
   }
   nextToken();
 }

Modified: cfe/trunk/unittests/Format/FormatTestJS.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTestJS.cpp?rev=302580&r1=302579&r2=302580&view=diff
==============================================================================
--- cfe/trunk/unittests/Format/FormatTestJS.cpp (original)
+++ cfe/trunk/unittests/Format/FormatTestJS.cpp Tue May  9 15:04:09 2017
@@ -367,6 +367,25 @@ TEST_F(FormatTestJS, GoogScopes) {
                "});");
 }
 
+TEST_F(FormatTestJS, IIFEs) {
+  // Internal calling parens; no semi.
+  verifyFormat("(function() {\n"
+               "var a = 1;\n"
+               "}())");
+  // External calling parens; no semi.
+  verifyFormat("(function() {\n"
+               "var b = 2;\n"
+               "})()");
+  // Internal calling parens; with semi.
+  verifyFormat("(function() {\n"
+               "var c = 3;\n"
+               "}());");
+  // External calling parens; with semi.
+  verifyFormat("(function() {\n"
+               "var d = 4;\n"
+               "})();");
+}
+
 TEST_F(FormatTestJS, GoogModules) {
   verifyFormat("goog.module('this.is.really.absurdly.long');",
                getGoogleJSStyleWithColumns(40));