[Lazarus] CodeTools: what is an "identifier"

[Mattias Gärtner]

Zitat von Bernd Kreuss <prof7bit at googlemail.com>:

> Mattias Gaertner wrote:
>
>> I wrote an example in codebrowser.pas:
>> function TCodeBrowserView.GetCodeHelp
>
> Thank you for this example. Now you effectively implemented almost all
> the things I wanted to do.

Sometimes it is easier to implement than to explain it in English. And  
I think in this case the implementation explains it better.


> My latest (not working) version before I read your answer was using
> Tool.BuildSubTreeAndFindDeepestNodeAtPos() and
> Tool.MoveCursorToProcName() and Tool.MoveCursorToPropName() and *almost*
> worked (worked in some cases but not always), sometimes the node that it
> returned was correct, sometimes it did not make any sense at all and
> began and ended at some completely wrong positions and had a completely
> wrong Desc.

Maybe you had edited in the source editor and not updated the code browser.
The code browser is meant to search hundreds of units which takes some  
time to scan. It would slow down the IDE quite a bit if it would  
update constantly.


> (btw: what is a "clean" position and what is the difference
> between just the absolute position and the clean position? Is this
> important or is there no difference at all? At one Point I tried a
> method that looked like it was supposed to convert column and line to a
> "cleanpos" but it returned a number three times as large as the entire
> file size)

See here
http://wiki.lazarus.freepascal.org/Codetools#How_the_codetools_parses_sources.2C_difference_to_a_compiler


> Please don't remove your comments in this example again, although they
> might seem obvious to anybody who knows the codetools, they are very
> helpful and explain things about the codetools that are not obvious from
> looking at the code alone. I would have for example never found the
> method CodeToolBoss.Explore() or known that I needed to call it (I have
> seen some of the examples but I didn't notice this method call before,
> probably because it is implicitely called by something else)

Every function has its pros and cons. Explore is great for the code  
explorer, but is often too much for simple tools. Doing too much means  
more things can go wrong. For example it can stop on syntax errors,  
that might be irrelevant for the intended function. And of course it  
can be too slow, for example when invoking it on every compiler  
hint/error/warning.


> and also I
> don't know what exactly LazarusIDE.BeginCodeTools() does.

It does some basic checks and commits the changes of the source editor  
to the codetools file caches.


> Because I felt that the reason for BuildSubTreeAndFindDeepestNodeAtPos()
> sometimes but not always returning anything useful was that the tool
> itself was not properly initialized, I was looking for something that
> would tell the tool to properly initialize itself and parse the whole
> file but I looked for a method of the codetool class and not a method of
> the codetoolboss. I tried Tool.BuildTree() but it didn't seem to help.

BuildTree is often enough.
CodeToolBoss is the next level and handles multiple units.
For example it checks if the main source has changed.


> The understanding of the codetools seems to be essential for doing any
> non-trivial thing inside the IDE. We need a document that describes the
> architecture of the codetools, the lifespan of such a tool, when and how
> to create it or where to find an instance of an already initialized
> tool, how to properly initialize it, what does happen internally when
> initializing it, generally what is going on inside these tool objects,
> what is needed for them to operate, what should be avoided, what can go
> wrong when using them, what is the codetoolboss and what is its role in
> this whole thing (I have now seen at least 3 or 4 ways of how and from
> where to get such a codetool instance and they all look slightly
> different), what steps are done by the boss and what steps are done by
> the tool, How does the whole containment hierarchy of these objects that
> are found "inside" (or belong to) other objects look like (maybe
> visualize it with a diagram), etc.

Another day.

Mattias