[SOLVED] macOS: TMemo.Lines vs TMemo.Text and PosEx()

[trev]

In the never-ending saga that is my application, I have discovered that my text search fails (ie using PosEx fails to correctly locate the search characters in the TMemo) if I assign lines read from a file to a TMemo using TMemo.Lines := strList rather than TMemo.Text := strList.Text.

It appears to me to be related to the number of lines and therefore likely the LineEndings are causing the issue.

macOS 10.14.5, Lazarus v2.10 (trunk), FPC 3.0.4 or FPC 3.3.1 (trunk).

Curiously it works fine under:

o  Ubuntu 18.04 64 bit with Lazarus v1.8.2; FPC v3.0.4;
o  FreeBSD 12.0 64 bit with Lazarus v2.00;  FPC v3.0.4; and
o  Windows 10 64 bit cross-compiled under macOS for 32 bit

using either method.

Easy enough to work around now that I figured out what is going on, but... I doubt it should be happening.

[skalogryz]

In the never-ending saga that is my application, I have discovered that my text search fails (ie using PosEx fails to correctly locate the search characters in the TMemo) if I assign lines read from a file to a TMemo using TMemo.Lines := strList rather than TMemo.Text := strList.Text.

It appears to me to be related to the number of lines and therefore likely the LineEndings are causing the issue.

where do you search at Memo.Text or Memo.Lines.Text? (something else?)

[marcov]

Did you use posex(substr,wholestr,value) and not  (wholestr,substr). Show more code.

[lucamar]

Note also that for memos it's best to use UTF8Pos() and UTF8RPos(). Pos(), PosEx(), RPos(), etc. tend to fail for anything other than single-byte character strings.

Another thing to take into account: The string functions return a 1-based position but SelStart, etc. are 0-based.

And that's not counting the problems with UTF8-BOM, ZWJs, etc.

[trev]

In the never-ending saga that is my application, I have discovered that my text search fails (ie using PosEx fails to correctly locate the search characters in the TMemo) if I assign lines read from a file to a TMemo using TMemo.Lines := strList rather than TMemo.Text := strList.Text.

It appears to me to be related to the number of lines and therefore likely the LineEndings are causing the issue.

where do you search at Memo.Text or Memo.Lines.Text? (something else?)

Code: Pascal  [Select][+][-]

1.   // we have a match...
2.   else
3.     begin
4.       // select characters to highlight
5.       Memo.SelStart := PosEx(UpperCase(Edit.Text), UpperCase(Memo.Text), searchOFS) - 1;
6.       Memo.SelLength := Length(Edit.Text);
7.       searchOFS := Memo.SelStart + 1;
8.     end;    
9.  

[trev]

Did you use posex(substr,wholestr,value) and not  (wholestr,substr). Show more code.

Yes, see above.

[trev]

Note also that for memos it's best to use UTF8Pos() and UTF8RPos(). Pos(), PosEx(), RPos(), etc. tend to fail for anything other than single-byte character strings.

The files contain PIC microcontroller config word settings, registers, interrupts etc and are definitely always going to be single byte characters... yeah, I know, famous last words

Another thing to take into account: The string functions return a 1-based position but SelStart, etc. are 0-based.

Aware and accounted for.

[lucamar]

Try using:

Code: Pascal  [Select][+][-]

1. Memo.Lines.AddStrings(StringList, True);

or even

Code: Pascal  [Select][+][-]

1. Memo.Lines.Assign(StringList);

Any of those should work right everywhere.

Also, I'm assuming (because your "we have a match") that you test that PosEx > 0 somewhere? If not your search should be more lke:

Code: Pascal  [Select][+][-]

1.   // we have a match...
2.   else
3.     begin
4.       searchOFS := PosEx(UpperCase(Edit.Text), UpperCase(Memo.Text), searchOFS);
5.       if searchOFS > 0 then begin
6.         Memo.SelStart := searchOFS - 1;
7.         Memo.SelLength := Length(Edit.Text);
8.       end else
9.         ShowMessage('Not found');
10.     end;

[skalogryz]

Code: Pascal  [Select][+][-]

1.       Memo.SelStart := PosEx(UpperCase(Edit.Text), UpperCase(Memo.Text), searchOFS) - 1;

try r61567 please

[trev]

Try using:

Code: Pascal  [Select][+][-]

1. Memo.Lines.AddStrings(StringList, True);

The assignment with the above takes approx 10s vs 1ms for:

Code: Pascal  [Select][+][-]

1. Memo.Text := strList.Text;

or even

Code: Pascal  [Select][+][-]

1. Memo.Lines.Assign(StringList);

Any of those should work right everywhere.

Only at the cost of a huge performance hit (28s): see https://forum.lazarus.freepascal.org/index.php/topic,45733.0.html

Also, I'm assuming (because your "we have a match") that you test that PosEx > 0 somewhere? If not your search should be more like:

You assumed right.

[trev]

try r61567 please

Thanks Dmitry - yes, that fixed the text location issue.

[skalogryz]

Thanks Dmitry - yes, that fixed the text location issue.

Keep that in mind: https://wiki.lazarus.freepascal.org/Cocoa_Internals/Text_Controls#Forcing_Lines_Breaks
(in case you need to load/save files across systems)