Overload

Overload is an esolang made by User:Fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff in 2024 that is inspired by Underload and Emmental. Its syntax is inspired by FALSE and Befunge. In Overload, you can redefine the instruction set.

Instructions

Overload's instructions can be redefined, so this is the initial instructions.

Caption text

Instuction	Description
'	Push the next character to the stack
:	Duplicate the top element of the stack
$	Delete the top element of the stack
!	Output the top element of the stack, popping it.
?	Push input on the stack
-	Swap top two elements of the stack
[]	Function declaration: Pop a symbol from the stack and define that to be the code inside the brackets. You may redefine a function that is being run.

EOF

EOF may vary across interpreters, however the recommended approach is to use the newline as EOF.

Conditionals

Overload doesn't have conditional statements, neither does it have an evaluation operator, so the only way to branch is to redefine the top element of the stack, then by executing a command.

For example, to test if the user's input is 1, and print "one" if it is:

?['e'n'o!!!]1

Programs

Hello, World!

'H!'e!'l::!!'o:!' !'W!!'r!!'d!'!!

Truth-machine

Define the user's input as ['1!1], then run 1. If the user inputted 1, it will go in an infinite loop.

?['1!1]1'0!

Cat program (infinite)

'*[?!*]

Cat program (halts)

'^['&[]?:![-]';'&
[^]$&]

Fixed Repeating Output (Input as unary)

'#['§]'=
',[?:[-]'*[]'@'=
'>[,]['>[]]@>],'
[]'%['*[]['1!%]]%0!

Minimization

Since the Turing-completeness proof for Overload only uses the initial instructions []', Overload only needs 3 instructions to be Turing complete.

However, for such people who request a 2-symbol version, a variant of Overload is described here:

2-command variation

Command	Description
:	Push the next character onto the stack
;	Pop two symbols off of the stack, a and b. Redefine a to the next c symbols; where c is 32 less than bʼs unicode ID.

At the end of the program the stack is printed

Examples

Hello World!: :H:e:l:l:o: :W:o:r:l:d:!

Infinite Loop: :?:!;?

Categories

(see Overload/Turing-completeness proof)