See https://ull-esit-gradoii-pl.github.io/practicas/egg-parser.html for a former description of the language
Go to https://github.com/ULL-ESIT-PL-2122/egg-oop-parser-template to download releases of evm for mac, linux and windows that are mostly compatible with this version of the parser. Specifically here: https://github.com/ULL-ESIT-PL-2122/egg-oop-parser-template/releases/tag/1.0.0
See file /src/egg.ne to see the syntax of this version that has support for objects and methods via brackets and dots.
Have a look at the examples folder.