[Lazarus] Adding units to a project

[Antonio Sanguigni]

Flávio Etrusco wrote:
>> 1) Logic should be separated from the presentation, so first there should be
>> 'TAbstractSynEdit' class, concerning itself purely with text manipulations,
>> such as text insertion/deletion, cursor position changes, text
>> attribute calculation,
>> save/loading, codetools etc.
>> TAbstractSynEdit should not depend on any visual code, in partucular it should
>> descend from TObject/TPersistent, not TControl.
>>     
>
> My vision deviates a bit from this in the sense that TAbstractSynEdit
> would just be an abstraction (or dedicated implementation) of a
> cleaner text manipulation interface (as TStrings won't cut it), which
> would also implement transparent/automatic/implicit 'undo' handling.
> Then each command would be a class, probably inheriting from TAction.
>   
Just read this, ....

I had the same idea, and am in progress with something like this.
I needed it to abstract layers of functionality. for example trimming 
trailing spaces. If it should work as a transparent plugin it needs 
access to undo/redo.

My current approach is:

- I separated SynEdit.Lines from the internal textbuffer (so textbuffer 
has no longer a need to be TStrings based (it still is, because i didn't 
take the time to change it))

- I add a few basic methods such as
  InsertText(x,y, substring); DeleteText,(x,y, len) ; BreakLine, 
JoinLine (maybe InsertNewLine, DeleteEntireLine)  [*]
  - they can deal with undo and redo
  - In SynEdit all operations can be reduced to the above (and don't 
care about undo/redo)

Since TrailingSpaces is already a wrapper around the TextBuffer, it can 
simply intercept those methods, and deal with them.

----
The only flaw I still have with this is, that currently all the 
SynEditText* (wrappers around the actual textbuffer, doing, spaces, 
tabs, folding....) are combining Display and Edit functionality.

It would be nice to be able to write a TSynDisplay class first, and 
inherit the editor from it....


Best Regards
Martin


[*]
of course insertText could detect newlines, but it  adds complexity. It 
will be simpler if SynEdit keeps control of this level, and InsertText, 
only operates on the current line