Are you trying to convert RegexBuilder.bas Class to a b4xlib libary?
If this is what you are aiming for:
then what I did is:
- start a new blank B4J console (non-UI) project
- added RegexBuilder.bas Class file downloaded from the forum post you referred to
- menu Project, Compile to Library
- I called the library "RegexBuilderTestLibrary" but presumably you can call yours whatever you like
- B4J created b4xlib in the Additional Libraries folder
- start a new blank B4J project
- right-click the list of libraries in the Libraries Manager tab, choose "Refresh"
- find and tick the new library
- type in the test code to make sure that B4J has included the Library and recognises the RegexBuilder Class