Variable == Function

In Amanatsu, variables and functions are equivilent.

A 'variable' (in other language terms) is just a function that pushes its stored value to the stack.

A 'function' (in other language terms) is just a variable that executes its stored value.

Simple Variables

They are defined in the same way, as shown below:

:meaning_of_life 42 define

The special name with a colon before it is known as an atom. It is effectively an identifier which conforms to the same naming requirements of functions (unlike strings which allow spaces).

Naming Requirements

The naming requirements for atoms/functions/variables are:

• Cannot contain a space
• Can only contain the letters a-z, as well as uppercase A-Z, underscores and finally numbers.
• Cannot start with a number

Proving Variables

We can add to the code snippet above to prove that the variables work.

:meaning_of_life 42 define

meaning_of_life print

This prints 42 to the terminal!

However, what if we want to define a function instead?

Simple Functions

We use the same define builtin, but we put square brackets around the value instead.

We can use this to push multiple values to the stack, as well as much more powerful things shown later.

:my_favourite_numbers [
    42 7 8 5
] define
#
Don't forget square brackets! 
They are critical as they allow the several numbers to form one value on the stack
#

Proving Functions

This pushes all the four values to the stack when you run the function as shown below:

:my_favourite_numbers [
    42 7 8 5
] define
my_favourite_numbers print

This prints 5, as the print function only consumes one value off the stack.

We can do the print function several times to consume the rest of the values.

:my_favourite_numbers [
    42 7 8 5
] define
my_favourite_numbers print print print print 

Whitespace is unimportant in Amanatsu, so this is valid code

This prints, in order:

• 5
• 8
• 7
• 42

Although, this code looks horribly inefficient.

Why don't we encapsulate the 4 print functions into one function?

Functions as Encapsulation

:show4 [
    print
    print
    print
    print
] define
:my_favourite_numbers [
    42 7 8 5
] define
my_favourite_numbers show4

That looks better!

If you want to improve this code even more, check the page on 'Iteration and Recursion'

We can now reuse our show4 function everytime we need to print 4 values, sweet!