Writing Commands

A command is a piece of code that can be run to control a unit or to get information about the world. Enu has many built in commands like forward, back, left, and right, and it's easy to add your own.

Commands start on a new line with a - and a space, followed by a name. If the command needs additional details to do its job you can list them in brackets separated by commas. Commands are blocks, so the first line ends with : and the command body is nested inside.

- hello(name):
  echo "hello ", name

- goodbye(name = "Vin"):
  echo "goodbye ", name

hello "Claire"
goodbye "Cal"

If a command produces a result its type must appear before the :. In the future this will be handled automatically.

- hello(name) string:
  result = "hello " & $name

echo hello("Scott")

Under the hood

Enu runs on the Nim language, and a command is just a Nim proc. Anything you can do with a command you can also do with a normal proc.

Command parameters (called details here) will default to Nim's auto type if no type is provided. Each parameter is shadowed by a mutable variable inside the command body.