[PATCH c++/objc++] Make Objective-c++ recognise lambdas.

[Iain Sandoe <iain_sandoe at mentor dot com>]

Hi,

The principle of Objective-c/c++ is that they should be supersets of the parent language.  Thus, it is intended that valid c++ (or c) should be parsed by the relevant objective-c/c++ FE.

While trying to build some external code, I found that lambdas confuse things at present for objcp.

When we find "[" and we're in objcp mode, and the "[" introduces a lambda, we try to parse a message expression and if that fails we punt (thus we are unable to recognise lambdas).

The attached patch tries "[" as a message expression introducer, if that fails it drops through to try for a lambda (no change intended for the non-objective-c++ path).

I guess it's a bit of a nuisance that the diagnostics from a failed message expression are likely to end up as mentioning a lambda.  Perhaps we might decide to punt early if we are both ObjC and < c++11.

This allows me to parse some necessary lldb headers with gcc objcp.

Thoughts / OK for trunk?
(I can raise a formal PR if you like).

Iain

gcc/cp:
	* parser.c (cp_parser_primary_expression): If parsing an objective-c++ message
	expression fails, see if a lambda is present.
	(cp_parser_objc_message_reciever): Don't assume that if a message reciever expression
	fails it is a hard error.

gcc/testsuite:
	* obj-c++.dg/lambda-0.mm New file.
	* obj-c++.dg/lambda-1.mm New file.

Attachment: objcp-lambdas.txt
Description: Text document