Lev comp
lev_comp is the NetHack special level compiler. It turns the text-format .des-files in the dat-dir into binary .lev-files which will be loaded by NetHack when making the special levels.
The des-file format is actually not a programming language, as NetHack always executes the different commands in the same order, eg. traps are created before monsters, which are created before objects, even if they're in a different order in the des-file.