A program interpreter which interprets and executes a numerical control
program can recognize predetermined mnemonics (script mnemonics) prepared
for instructions for setting, loading, and executing script programs.
When the program interpreter recognizes the script mnemonic during
interpretation and execution of the numerical control program, the
program interpreter instructs execution of the script program (instance)
indicated in the parameter of the mnemonic to a script engine. The script
engine executes the instructed script program.