[Qt-creator] Need help understanding some qt-creator source

[Typz]

It does not help the semantic analyzer in your case, but would help if used to make some function names unique for example.

Generally, this is really just the "normal" preprocessor behavior, which is required in any case.

The problem is not that the token is being replaced, but instead that the replacement itself is not properly handled: for regular macros, it works just fine.

Btw, it can be noted that these special macros are also not highlighted.

-- 
Francois

On 10 sept. 2013, at 18:31, Simon Schäfer <simonschaefer at posteo.de> wrote:

> Am 10.09.13 16:28, schrieb Erik Verbruggen:
>> On Sep 10, 2013, at 14:57, Simon Schäfer <simonschaefer at posteo.de> wrote:
>> 
>>> Hello
>>> 
>>> I try to understand some of the code of the creator, because I would
>>> like to remove it, it is the reason of a bug (QTCREATORBUG-8036, it
>>> still effects master) that annoys me. I can't figure out what it is used
>>> for. The code I am talking about is in pp-engine.cpp:
>>> 
>>> bool Preprocessor::handleIdentifier(PPToken *tk)
>>> 
>>> There the representations of some preprocessor macros are internally
>>> replaced by their meanings. For Example __LINE__ is replaced by the text
>>> "9". This leads to strange behaviour for highlighting and even
>>> re-factoring, because the editor determines the length of a token not by
>>> the space it uses in the view but by the length of its text. So for the
>>> above example the length is 1 instead of 8.
>>> 
>>> The following example code can help you understand the Problem:
>>> 
>>> <snip>
>>> #include <QCoreApplication> // line 1
>>> 
>>> #include <QDebug>
>>> 
>>> int main(int argc, char *argv[])
>>> {
>>>    int abcd = 0;
>>> 
>>>    qDebug () << __LINE__ << abcd; // line 9
>>>    qDebug () << __LINE__ << abcd; // line 10
>>>    return 0;
>>> }
>>> <snap>
>>> 
>>> If you click on abcd it will highlight a block of 4 chars within the
>>> first __LINE__ and another block of 4 in the second __LINE__ (moved one
>>> to the right). If you now use "Rename Symbol under cursor" and type
>>> abcde strange stuff happens.
>>> 
>>> My basic question is why are those Preprocessor texts used instead of
>>> the displayed texts?
>> Um, because semantic highlighting uses information from the parser to find out that a piece of text is an identifier, and actually the identifier it needs to highlight? Or did I misunderstand the question?
> How does it help the semantic highlighter that __LINE__ is replaced by a
> string representation of the current line number or __FILE__ is for
> example: "helloworld.cpp"?
> What I would like to commit is the following: http://pastebin.com/3AZvPj2e
> What keeps me holding it back is that the txt's where there for a reason
> in the first place, but I can't figure out what they are for.
> 
> Cheers
> Simon
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