Use the Analyzer class to get the tree root of parsed PL/SQL source file. Create your own application to recognize the parsed tree.
As SQL grammar are normally not case sensitive but this grammar implementation is, you must use a custom character stream that converts all characters to uppercase before sending them to the lexer. You could find more information here with implementations for various target languages.
The C# source was generated from *.g4 grammer files with ANTLR 4.8 tool.
Original PL/SQL grammar can be found here. Current used version of this grammer is 19-JAN-2020 (PL/SQL 11g)
If you want to rebuild CSharp source run GenerateSrc.ps1
or GenerateSrc.sh
More information about build for C# can be found here