Changed the grammar for out parameters to deprecate the semicolon syntax

    and use an "out" keyword instead. The old syntax still works, but now
    prints a warning. Fixed up all the test cases that got broken by this
    and add a new test case for out-of-order in and out parameters.
    Refactored the grammar somewhat because, initially, out params added
    something like 50 shift/reduce conflicts. One shift/reduce conflict
    remains, caused by the addition of ICE_OUT to the last production in
    Grammar.y. We could avoid the conflict by removing ICE_OUT from that
    production, but then we wouldn't catch other errors anymore, such as an
    attempt to use "out" as the name of an operation or interface. I've
    added a warning to the Makefile to expect 1 shift/reduce conflict when
    Grammar.y is rebuilt.

1 files changed, 8 insertions, 1 deletions

diff --git a/cpp/src/Slice/Parser.cpp b/cpp/src/Slice/Parser.cpp
index cea765dc172..8fd318910e1 100644
--- a/cpp/src/Slice/Parser.cpp
+++ b/cpp/src/Slice/Parser.cpp
@@ -1352,7 +1352,14 @@ Slice::ClassDef::createOperation(const string& name,
 	    ++q;
 	    while (q != allParams.end())
 	    {
-		if (p->second == q->second)
+		//
+		// Complain about duplicate parameters only if they are
+		// non-empty; otherwise, we get a complaint about duplicates
+		// if two or more parameter names are missing in an operation
+		// signature (but the missing parameters have been reported
+		// already).
+		//
+		if (p->second == q->second && p->second != "")
 		{
 		    string msg = "duplicate parameter `";
 		    msg += p->second;