Basics - Nazek42/arcyou GitHub Wiki

Atoms

An atom in Arcyóu is a numeric literal like 3.14, a string literal like "foobar", or a variable reference like my-variable.

Literals evaluate to themselves. Variables evaluate to their value.

Note: string literals adjacent to other atoms must be separated by spaces. Example: x "foobar" 2, not x"foobar"2.

Cells

A cell is a combination of one or more atoms in parentheses, like so:

(p "Hello, World!" 8 super-special-string)

A cell can either be a function call or a special form. A special form is a cell where the first atom is one of the following:

• ?
• @
• f
• :
• F
• '

If the first atom is anything else, the cell is a function call.

Function Calls

Function calls are of the form (func arg1 arg2 arg3 ...). Where most languages would have built-in operators for things like addition and subtraction, Arcyóu has built-in functions. For example:

(+ 1 2) --> 3
(= 2 3) --> False
(_ 2 5) --> [2, 3, 4]
(* 5 4 3 2) --> 120

This means that you can redefine things like + or _ to be whatever you want. Use this power wisely!

Special Forms

The other type of cell is a special form. These are things that are necessary in the language, but don't quite conform to the syntax rules of a function call. There are six special forms in Arcyóu.

Atom	Meaning	Syntax	Example
?	If statement	(? condition if-true if-false)	(? (= x 3) "x is 3" "x is not 3")
@	While loop	(@ condition loop-body)	(@ (< x 6) (p (+ x 1)))
f	For loop	(f variable iterable loop-body)	(f n my-list (p n))
:	Set variable	(: symbol value)	(: my-number -7.2)
F	Anonymous function	(F (arguments) (function-body))	(F (x y) (+ x y))
'	Quote	(' anything)	(' 1 2 3 4)