Use the flake with all compilers included:
nix develop
or, if you prefer direnv
direnv allow
Build idris project
idris2 --build catsEffect.ipkg
then build the wrapper jar with mill and copy it to the same folder as the output from idris
mill catsEffectIdris.assembly
cp out/catsEffectIdris/assembly.dest/out.jar build/exec/test_app/
Finally we can execute the sample app:
./build/exec/test