addict

A simple language for a simple time https://ethproductions.github.io/addict

Spec

Addict is a Turing tarpit based on PRINDEAL, a non-Turing-complete variable-based language where the only commands are PRint, INcrement, DEcrement, and ALias.

Variables

A variable name matches the regex /^[A-Za-z_]\w*$/. All variables start out with a value of 0, and can only contain non-negative integers.

A variable can also have a dynamic name; for example, abc[var]xyz. The [var] returns the value of var; if var is currently 7, this returns the variable abc7xyz.

You can also nest dynamic names: a[b[c]]

Commands

i x - increment variable x by 1. Succeeds unless no arg is given.
d x - decrement variable x by 1. Succeeds unless no arg is given, or the arg is already at 0.
t x - set variable x to the next charcode from input. Succeeds unless EOF. (Correctly handles Unicode chars above U+FFFF.)
c x - output variable x as a charcode. Succeeds unless no arg is given. (Correctly handles charcodes above 0xFFFF.)
n x - output variable x as a number. Succeeds unless no arg is given.

Aliases

Aliasing has very specific syntax:

a commandname
 command1
 command2
 command3

This creates a new command called commandname. Whenever commandname is called, the following process happens:

command1 is called.
If command1 succeeded, run command2.
If command1 failed, run command3.

You can send arguments to the alias, too. The nth argument is called using n. For example:

a zero  # Sets the input variable to 0:
 d 1    #   Decrement the input var.
 zero 1 #   If decrementing succeeded, run `zero` on the var again.
 i _    #   Otherwise, return success.

This can then be called as zero myVar, and it will set myVar to 0.

Note: 0 is always 0, no matter what you do to it.

Sometimes you'll want to grab the nth argument, but n is a variable. This can simply be done with [n]. Be careful with using numbers, though: [1] will not return the first argument; it will return the argument at index [value of 1st argument].

Additionally, you can select groups of arguments:

 myFunc *    # Call myFunc with all arguments
 myFunc 1*   # Call myFunc with all but the first argument
 myFunc *1   # Call myFunc with only the first argument
 myFunc -1*  # Call myFunc with only the last argument
 myFunc *-1  # Call myFunc with all but the last argument
 myFunc 1*3  # Call myFunc, excluding the first argument and anything after the third
 myFunc 1*-1 # Call myFunc with all but the first and last arguments
 # etc.

Example programs

`cat`

a input  # Define a command `input` that does the following:
 t char  #   Set variable `char` to the next charcode in the input.
 output  #   If there is a next charcode, run command `output`.
 d       #   Otherwise, just exit.

a output # Define a command `output` that does the following:
 c char  #   Output variable `char` as a charcode.
 input   #   Attempt to input again.
 d       #   (This line never gets run.)

input  # Run command `input`.

ETHproductions / addict