Help with search and repalce whole word without case sensitivity

[zxandris]

Okay so I'm using Lazarus 4.2, and I'm trying to take a string then search and replace by whole word, but not worrying about case.  I have some functions I got from the net but they appear to be trimming somehow.  I can't for the life of me figure out how, it seems to trim like #9 #10#13 etc, but as far as I can tell it shouldn't be.  I've tried to account and it's still not working.

My functions

Code: Pascal  [Select][+][-]

1. function IsWordChar(ch: Char): Boolean;
2. begin
3.   // Letters and digits are word characters. Include '_' if you want underscore to count as part of words.
4.   Result := TCharacter.IsLetterOrDigit(ch) or (ch = '_');
5. end;
6.  
7. function PosWholeWordInsensitive(const Sub, S: string; StartPos: Integer = 1): Integer;
8. var
9.   i, LSub, LStr: Integer;
10.   Hay, Needle: string;
11.   beforeOK, afterOK: Boolean;
12. begin
13.   Result := 0;
14.   if (Sub = '') or (S = '') then Exit;
15.   if StartPos < 1 then StartPos := 1;
16.  
17.   LSub := Length(Sub);
18.   LStr := Length(S);
19.   if StartPos > LStr - LSub + 1 then Exit;
20.  
21.   // Use Unicode-aware case folding; UpperCase is OK for many RTLs. Replace with proper casefold if available.
22.   Hay := UpperCase(S);
23.   Needle := UpperCase(Sub);
24.  
25.   i := StartPos;
26.   while i <= LStr - LSub + 1 do
27.   begin
28.     if Copy(Hay, i, LSub) = Needle then
29.     begin
30.       // check char before match (if any)
31.       if i = 1 then
32.         beforeOK := True
33.       else
34.         beforeOK := not IsWordChar(S[i - 1]);
35.  
36.       // check char after match (if any)
37.       if i + LSub - 1 = LStr then
38.         afterOK := True
39.       else
40.         afterOK := not IsWordChar(S[i + LSub]);
41.  
42.       if beforeOK and afterOK then
43.       begin
44.         Result := i;
45.         Exit;
46.       end;
47.     end;
48.     Inc(i);
49.   end;
50. end;
51.  

The Search and Replace

Code: Pascal  [Select][+][-]

1. function strSearchReplaceWholeAll(const strText, strToReplace, strReplaceWith : String) : String;
2. var
3.    ps : Integer;
4.    a : Integer;
5.    rtn : String;
6.    txtBefore, txtAfter : String;
7. begin
8.      rtn := strText;
9.      if (trim(rtn)<>'') and (trim(strToReplace)<>'') then
10.      begin
11.           try
12.              ps := posWholeWordInsensitive(strToReplace, rtn, ps);
13.              while ps>0 do
14.              begin
15.                  txtBefore := subStr(rtn, 1, ps-1);
16.                  txtAfter := subStr(rtn, (ps + length(strToReplace)), length(rtn));
17.  
18.                  if (rtn[ps-1]=#10) then
19.                     rtn := #10 + txtBefore + strReplaceWith + txtAfter
20.                  else if (rtn[ps-1]=#13) then
21.                       rtn := #13 + txtBefore + strReplaceWith + txtAfter
22.                  else if (rtn[ps-1]=#13) then
23.                       rtn := #13 + txtBefore + strReplaceWith + txtAfter
24.                  else if (rtn[ps-1]=#9) then
25.                       rtn := #9 + txtBefore + strReplaceWith + txtAfter;
26.  
27.  
28.                  if (rtn[ps+length(strToReplace)]=#10) then
29.                     rtn := txtBefore + strReplaceWith + #10 + txtAfter
30.                  else if (rtn[ps+length(strToReplace)]=#13) then
31.                     rtn := txtBefore + strReplaceWith + #13 + txtAfter
32.                  else if (rtn[ps+length(strToReplace)]=#9) then
33.                       rtn := txtBefore + strReplaceWith + #9 + txtAfter
34.                  else
35.                      rtn := txtBefore + strReplaceWith + txtAfter;
36.  
37.  
38.                  ps := ps + length(strReplaceWith);
39.                  ps := posWholeWordInsensitive(strToReplace, rtn, ps);
40.                  if (ps>=length(rtn)) or (ps<=0) then break;
41.              end;
42.           except
43.                 //
44.           end;
45.      end;
46.      result := rtn;
47. end;
48.  

It's probably a mess, or I'm missing something obvious but would really LOVE some help on this it's driving me insane! lol

Thanks

CJ

[BlueIcaro]

Hello, you can use functions included in strutils unit
https://www.freepascal.org/docs-html/rtl/strutils/index-5.html

You can search for number of words with wordcount https://www.freepascal.org/docs-html/rtl/strutils/wordcount.html

You can replace a text with ReplaceText https://www.freepascal.org/docs-html/rtl/strutils/replacetext.html

Take a look to this unit, has many functions and prodedures to work with strings, and many of them has their variant for insensitive case

/BlueIcaro

[Thaddy]

Code: Pascal  [Select][+][-]

1. {$mode objfpc}{$H+}
2. uses sysutils;
3.  
4. var
5.   a:string = 'IoPUkIoUkIOPuk';  // <--- can be a whole file!
6. begin
7.   writeln(a.Replace('Io',' -Test-', [rfReplaceAll]));             //case sensitive
8.   writeln(a.Replace('Io',' -Test-', [rfReplaceAll,rfIgnoreCase]));//case ignored.
9. end.

It is not much simpler than that, is it?

[CM630]

This should be working search and replace code; the Lazarus inbuilt one used to cause problems, possibly it was fixed in recent years.

https://forum.lazarus.freepascal.org/index.php/topic,26137.msg274687.html#msg274687

[avk]

Code: Pascal  [Select][+][-]

1. {$mode objfpc}{$H+}
2. uses sysutils;
3.  
4. var
5.   a:string = 'IoPUkIoUkIOPuk';  // <--- can be a whole file!
6. begin
7.   writeln(a.Replace('Io',' -Test-', [rfReplaceAll]));             //case sensitive
8.   writeln(a.Replace('Io',' -Test-', [rfReplaceAll,rfIgnoreCase]));//case ignored.
9. end.

It is not much simpler than that, is it?

This approach seems to have a small drawback: TReplaceFlags does not have the rfWholeWordsOnly flag.

... the Lazarus inbuilt one used to cause problems, possibly it was fixed in recent years ...

I also remember that String.Replace() was buggy.

[jamie]

CompareText is case insensitive

Jamie

[zxandris]

Thanks peeps,

I will look into those, I think the biggest thing is that it needs to replace whole words so 'ThisIsAString' replacing with replace would replace say 'This' which is part of the string where as I would only want to replace 'This Is a string', the 'This' in that is what I'd want to replace not the one that is part of the first.

See what I mean, I feel I'm not explaining that well but I can't think of another way of putting it.

[avk]

It looks like you're trying to use Delphi code(uses UTF-16 strings) in Lazarus(uses UTF-8 strings).

You could try this modified version:

Code: Pascal  [Select][+][-]

1. function IsWordChar(ch: WideChar): Boolean;
2. begin
3.   // Letters and digits are word characters. Include '_' if you want underscore to count as part of words.
4.   Result := TCharacter.IsLetterOrDigit(ch) or (ch = '_');
5. end;
6.  
7. function PosWholeWordInsensitive(const Sub, S: unicodestring; StartPos: Integer = 1): Integer;
8. var
9.   i, LSub, LStr: Integer;
10.   Hay, Needle: unicodestring;
11.   beforeOK, afterOK: Boolean;
12. begin
13.   Result := 0;
14.   if (Sub = '') or (S = '') then Exit;
15.   if StartPos < 1 then StartPos := 1;
16.  
17.   LSub := Length(Sub);
18.   LStr := Length(S);
19.   if StartPos > LStr - LSub + 1 then Exit;
20.  
21.   // Use Unicode-aware case folding; UpperCase is OK for many RTLs. Replace with proper casefold if available.
22.   Hay := ToUpper(S);
23.   Needle := ToUpper(Sub);
24.  
25.   i := StartPos;
26.   while i <= LStr - LSub + 1 do
27.   begin
28.     if Copy(Hay, i, LSub) = Needle then
29.     begin
30.       // check char before match (if any)
31.       if i = 1 then
32.         beforeOK := True
33.       else
34.         beforeOK := not IsWordChar(S[i - 1]);
35.  
36.       // check char after match (if any)
37.       if i + LSub - 1 = LStr then
38.         afterOK := True
39.       else
40.         afterOK := not IsWordChar(S[i + LSub]);
41.  
42.       if beforeOK and afterOK then
43.       begin
44.         Result := i;
45.         Exit;
46.       end;
47.     end;
48.     Inc(i);
49.   end;
50. end;
51.  
52. function strSearchReplaceWholeAll(const strText, strToReplace, strReplaceWith : unicodestring) : string;
53. var
54.    ps : Integer;
55.    a : Integer;
56.    rtn : unicodestring;
57.    txtBefore, txtAfter : unicodestring;
58. begin
59.      rtn := strText;
60.      if (trim(rtn)<>'') and (trim(strToReplace)<>'') then
61.      begin
62.           try
63.              ps := posWholeWordInsensitive(strToReplace, rtn, ps);
64.              while ps>0 do
65.              begin
66.                  txtBefore := Copy(rtn, 1, ps-1);
67.                  txtAfter := Copy(rtn, (ps + length(strToReplace)), length(rtn));
68.  
69.                  if (rtn[ps-1]=#10) then
70.                     rtn := #10 + txtBefore + strReplaceWith + txtAfter
71.                  else if (rtn[ps-1]=#13) then
72.                       rtn := #13 + txtBefore + strReplaceWith + txtAfter
73.                  else if (rtn[ps-1]=#13) then
74.                       rtn := #13 + txtBefore + strReplaceWith + txtAfter
75.                  else if (rtn[ps-1]=#9) then
76.                       rtn := #9 + txtBefore + strReplaceWith + txtAfter;
77.  
78.  
79.                  if (rtn[ps+length(strToReplace)]=#10) then
80.                     rtn := txtBefore + strReplaceWith + #10 + txtAfter
81.                  else if (rtn[ps+length(strToReplace)]=#13) then
82.                     rtn := txtBefore + strReplaceWith + #13 + txtAfter
83.                  else if (rtn[ps+length(strToReplace)]=#9) then
84.                       rtn := txtBefore + strReplaceWith + #9 + txtAfter
85.                  else
86.                      rtn := txtBefore + strReplaceWith + txtAfter;
87.  
88.  
89.                  ps := ps + length(strReplaceWith);
90.                  ps := posWholeWordInsensitive(strToReplace, rtn, ps);
91.                  if (ps>=length(rtn)) or (ps<=0) then break;
92.              end;
93.           except
94.                 //
95.           end;
96.      end;
97.      result := string(rtn);
98. end;
99.  

But from a performance point of view, this code is a real disaster.

[Zvoni]

Why not use Regex with Word-Boundary?

TRegExpr-Unit even contains "Substitute/Replace"-Functions

https://regex101.com/r/x29RTc/2

https://regex.sorokin.engineer/tregexpr/

[avk]

Why not use Regex with Word-Boundary?

TRegExpr-Unit even contains "Substitute/Replace"-Functions
...

IIRC, the TRegExpr that came with the FPC packages was not unicode-aware.
Has anything changed in this regard now?

[Zvoni]

Why not use Regex with Word-Boundary?

TRegExpr-Unit even contains "Substitute/Replace"-Functions
...

IIRC, the TRegExpr that came with the FPC packages was not unicode-aware.
Has anything changed in this regard now?

--> https://regex.sorokin.engineer/tregexpr/#unicode

Unicode

In Unicode mode, all strings (InputString, Expression, internal strings) are of type UnicodeString/WideString, instead of simple "string". Unicode slows down performance, so use it only if you really need Unicode support.

To use Unicode, uncomment {$DEFINE UniCode} in regexpr.pas (remove off).

Maybe Andrey or Alexej will chip in here.

Though i just looked into the mentioned file which came with fpc3.2.2, and i can't find the mentionend commented Define.
I found it in "uregexpr.pp" though, which INCLUDES regexpr.pas
So it's probably just either
1) inserting a {$DEFINE UniCode} at the beginning of regexpr.pas
2) a "UniCode"-Constant in Project-Options
3) include "uregexpr" in Uses instead of "regexpr" (Everyone can have a guess, what the "u" in the unit-name stands for.....)

[zxandris]

As per RegExp, I have quite literally no idea how to use it, so any tips on how to do this in regExp would be appreciated

[Thaddy]

RexEx are not for noobs. But it can be done. Will add example later.

[Zvoni]

As per RegExp, I have quite literally no idea how to use it, so any tips on how to do this in regExp would be appreciated

You mean besides the fact, that i posted links to an online-Regex-Tool with an example, where the online-tool even explains what it is doing,
and the official documentation of the Regexpr-Unit?

[zxandris]

Ahh, I didn't so much mean the class, as actual regexp. i.e. how to use regex to do things.  I will read the site as per the component but the actual regex I don't so much know a thing about how to use it I'm afraid.  Shockingly enough, so far, I've not found a need for it, but I suspect I have one now.

As per RegExp, I have quite literally no idea how to use it, so any tips on how to do this in regExp would be appreciated

You mean besides the fact, that i posted links to an online-Regex-Tool with an example, where the online-tool even explains what it is doing,
and the official documentation of the Regexpr-Unit?