Install ANTLR4:

cd "<absolute_project_root>"
alias antlr4="java -Xmx500M -cp \"$(realpath .)/lib/antlr-4.8-complete.jar:\$CLASSPATH\" org.antlr.v4.Tool"

To scaffold a proper ANTLR project run the following from the project root:

cd ./grammar
antlr4 -o ../src/ua/nure/lnu2020/ofp_4dv507/pashaieva_shevchenko/parsing ./OfpPashaievaShevchenko.g4 -long-messages -visitor -listener

To compile the program from CLI:

javac -d ./out/production/antlr4-lang/ ./src/ua/nure/lnu2020/ofp_4dv507/pashaieva_shevchenko/**/*.java

To use grun:

cd ./out/production/antlr4-lang/ua/nure/lnu2020/ofp_4dv507/pashaieva_shevchenko/
grun OfpPashaievaShevchenko start -tree # doesn't work with package names