How to get the source code of the Regex Text Function buit-in in Calc ?

Calc: I need to know where exactly is the source code of the Regex Function that is included as a text function in LIbre Office Calc. I have downloaded the complete project’s LibreOffice source code, but I was not able to find or localize the file with an extension c++ or cxx or whatsoever, containing such code. I would need the file name where such code is stored. Any assistance is much appreciated.

May be this commit, which resolves tdf#113977 - implement REGEX() spreadsheet function, provides the references to the source code: libreoffice/core - main, development code repository

Maybe it is enough for you to call the function REGEX() through the LO API…
It is possible to call the Calc functions from a macro code (even it run in an another application…)

Use the objec

oFunctionAccess = createUnoService( "" )

See the sample code here: