Your First Program

Create hello.ilo:

ilo

greet name:t > t
  +"hello " name

Run it:

Shell

ilo hello.ilo greet "world"
# → hello world

That’s a complete ilo program. Here’s what each part means:

Part	Meaning
greet	function name
name:t	parameter name, type text
> t	returns text
+"hello " name	body: concatenate two strings (prefix +)

Now try something with numbers. Create math.ilo:

ilo

add a:n b:n > n  -- n = number, t = text
  + a b          -- prefix: + a b means a + b

Shell

ilo math.ilo add 3 4
# → 7

Inline mode

You can also run ilo without a file. Semicolons replace newlines and indentation:

Shell

ilo 'add a:n b:n>n;+a b' 3 4
# → 7

This is the form AI agents use - same language, just compressed to one line. See the CLI Reference for more.