More prep work for macro expansion. Replaced Lexer with a stack of lexers. Introduced a Lexer bas...

More prep work for macro expansion. Off-loaded lexing from Context class to a new Lexer class.
Committed: https://code.google.com/p/angleproject/source/detail?r=1011

[kbr1, 2011-09-19 21:04:43]

LGTM. Couple of comments.

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
File src/compiler/preprocessor/new/Context.h (right):

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
src/compiler/preprocessor/new/Context.h:32: void pushLexer(Lexer* lexer);
Please document that the Context takes ownership of the Lexer object.

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
src/compiler/preprocessor/new/Context.h:33: void popLexer();
Is there any reason not to delete the lexer in the implementation of popLexer,
and document that this is done?

[Alok Priyadarshi, 2011-09-19 21:09:37]

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
File src/compiler/preprocessor/new/Context.h (right):

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
src/compiler/preprocessor/new/Context.h:32: void pushLexer(Lexer* lexer);
On 2011/09/19 21:04:43, kbr1 wrote:
> Please document that the Context takes ownership of the Lexer object.

Actually it does not. The context should only delete the BufferLexer it pushes.
May be I need an ASSERT in reset().

http://codereview.appspot.com/5059048/diff/1/src/compiler/preprocessor/new/Co...
src/compiler/preprocessor/new/Context.h:33: void popLexer();
On 2011/09/19 21:04:43, kbr1 wrote:
> Is there any reason not to delete the lexer in the implementation of popLexer,
> and document that this is done?

We might end up letting Context own the passed Lexer, but thats not what I
intend to do at present. I might change the design depending on how the
implementation shapes.

[dgkoch, 2011-10-03 11:51:06]

no issues from me on this.