pcre does not work in $replacerx

Only just noticed this so not sure when it popped up but it is present in at least 3815-3817

Using pcre in $replacerx() does not work. Noticed this while attempting to remove a trailing / with $replacerx("%p","rx: /$","") and subsequent testing confirmed that any pcre fails. I tried several formats of the command with/without the quotes around <find> field, with/without the rx: prefix, combinations of both, etc. I also tried simply replacing a single alphanumeric character to no avail.

I will need to test older builds to determine if this behavior has changed, but I don't think it has.

I just noticed that the help file on this command very wrong and doesn't explain how this command works.

$replacerx("<input>", "<pattern>", "<replacement>")

/echo $replacerx("/this/is/my/end/game/", "(.*)/$", "\1")

Output:
[CMD] /this/is/my/end/game

all text up until the last / is stored in token \1 matching (.*)

Ah, the help file suggests it works in the same manner as $replace. (which would be more naturally expected)

Your example above suggests that $replacerx() is actually a general regular expression string manipulation rather than a substitution algorithm. Since pcre doesn't actually include a native function for substitution making $replacerx() work in the same manner as $replace would require manipulation using the regmatch_t array argument of regexec (and memory manipulation) or possible pcrs extention (which I am not familiar with but is available from pcre.org).

Although it would make writing the expressions in $replacerx() more natural (and simpler) it's possibly not worth the effort to implement.

Adjusting the modifier description and a good example should probably suffice to dispel the assumption that is works like $replace(). As you say the argument names are not very accurate so <replacement> should actually be <output> or similar.

I reviewed the source code and it appears that this is how the token modifier has always behaved.

After conducting some more tests and doing a fair bit of research it appears that some of the functionality provided by this function is not correct. Our function should (or at-least I thought it did) provide results similar to that of preg-replace() in PHP (however it doesn't)

The following example returns the wrong result, when the replacement is blank the pattern should be removed from the result.

/echo $replacerx("/this/is/my/path/", "/$", "")

Instead we get a result of
[CMD] /this/is/my/path/
(This is because on PCRE failure or error the original string is returned as the result)

The code wasn't handling an empty replacement very well and it resulted in a failure.

I have corrected this for the next release.

Taking a slightly modified example from the preg-replace PHP webpage the following code would replace brown with black but it doesn't.

/echo $replacerx("The quick brown fox jumped over the lazy dog.", "brown", "black")

[CMD] black

Instead we get a result of black, I'm not sure what's going on here and I will need to investigate this issue further.

If we modify the pattern and replacement to use back references then everything works as expected.

/echo $replacerx("The quick brown fox jumped over the lazy dog.", "(.*)brown(.*)", "\1black\2")

I will need to investigate this further to fully understand why it doesn't work, its possible that its a mistake in my code or a limitation in the 3rd party helper functions I'm using.

The partial fix I mentioned above has been implemented in FlashFXP v5.1 build 3818

The secondary issue I discovered with trying to replace brown with black is still under investigation and hopefully it can be resolved in a future build.

Okay I think I got everything fixed and working correctly now, below are the tests that I performed.

/echo $replacerx("/my/path/test/", "/$", "")

[CMD] /my/path/test

/echo $replacerx("The quick brown fox jumped over the lazy dog.", "brown", "black")

[CMD] The quick black fox jumped over the lazy dog.

/echo $replacerx("This job is 65% complete.", "\d+", "100")

[CMD] This job is 100% complete.

/echo $replacerx("FlashFXP51_3818_Setup.exe", "^(\w+\d+)_(\d+)_(.*)$","\1_\3")

[CMD] FlashFXP51_Setup.exe

/echo $replacerx("The quick brown fox jumped over the lazy dog.", ".+", "\i0")

[CMD] The Quick Brown Fox Jumped Over The Lazy Dog.

/echo $replacerx("The quick brown fox jumped over the lazy dog.", ".+", "\l0")

[CMD] the quick brown fox jumped over the lazy dog.

/echo $replacerx("The quick brown fox jumped over the lazy dog.", ".+", "\U0")

[CMD] THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG.

.... And here's an updated build with the changes
Download ffxp5.1.0.3819.zip

Just out of curiosity what library are you using and what was the problem? When you mentioned that capturing groups / referencing corrected that example it again led me to the difference between a normal string manipulation function and a substitution function but your comments suggest that may not be the case.

For regex replace I'm using TPerlRegEx from http://www.regular-expressions.info/delphi.html

I have a helper function that interfaces with the TPerlRegEx object class and my helper contained a flaw which in turned caused certain operations to fail.