Re: [Opencxx-users] parse error on valid code

[Stefan S. <se...@sy...>]

Grzegorz Jakacki wrote:

>> what does 'ClassWalker' do ? The name suggests it is only inspecting
>> class definitions, but not you are suggesting it deals with arbitrary
>> type recovery.
> 
> 
> AFAIK it traverses the AST and registers all definitions and 
> declarations in the Environment it maintains.
> 
>>> This is fair enough when there is no namespaces or nested templates. 
>>> However, if top-level construct is a namespace, then Environment does 
>>> not have a clue about anything defined in it until it is fully parsed.
>>
>>
>>
>> hmm, I don't understand the design of Environment et al. yet. Why doesn't
>> it 'have a clue' until it is 'fully parsed' ? In the example
>>
>> namespace Foo
>> {
>> typedef int Int;
>> typedef std::vecor<Int> IntVector;
>> }
>>
>> Shouldn't it know 'Int' when it sees the typedef for IntVector ?
> 
> 
> The top-level loop will call parser. Parser will return AST representing 
> all the above text. At this moment the text is already parsed, but 
> Environment object still does not know anything about Int or IntVector. 
> Only now the main loop calls ClassWalker, which begins to traverse the 
> AST. The traversal reaches first typedef and registers Int in top-level 
> Environment, then second typedef and registers IntVector.
> 
> So, Environment does not know about Int or IntVector until the parsing 
> of the whole namespace ends.

well, but as we just discovered, this doesn't work for C++ in general where
certain ambiguities have to be resolved using the knowledge about previously
declared types, variables, etc.

>> Please document the current design and the solutions you envision. It 
>> will
>> help a lot to work out the remaining issues to make opencxx a very 
>> powerful
>> tool that supports all standard C++.
> 
> 
> I am putting it really high on my TODO list, I will try to post it this 
> week. As for existing design, however, my knowledge is limited to what I 
> absorbed or figured out, so I am afraid there are going to be some dark 
> corners.

Yeah. But if we have very specific questions I'm sure we can always get
back to Chiba to help us out.

>> More and more people use synopsis, and the bug reports about parse errors
>> I get become more and more sophisticated, indicating that it becomes more
>> and more important to make the parser work correct not only for the most
>> used C++ features, but really covering the full standard.
> 
> 
> That's great news. There is still a lot of work, but let's keep moving 
> forward.

Sure. I'm aiming for a new synopsis release within the coming week, and
after that I'll start working on a refactoring of the opencxx code synopsis
uses. I'm sure I'll have lots of questions in the process...

Regards,
		Stefan