DDuuaall

DDuuaall is a language invented by User:A, inspired by Vyxal's zipmap.

Special Arity Rules

The so-called complement is usually number negation for numbers, or reversing for strings/lists.

Nilads

You push a nilad along with its complement, the complement is pushed after the original nilad.

Monads

You apply the defined operation, along with a "complement-operation". The result of the complement operation is pushed after the intended operation.

Dyads

With two list operands, it vectorizes, if possible (unless the instruction defines otherwise). When the TOS is a list operand, it reduces the dyad by the list.

With a list operand on the bottom and a number operand on the top, the instruction implements its own method of evaluation.

Instruction list

Instruction	Main behavior	Complement behavior
\ (Triad)	Triple swap: a b c -> c a b	-
= (Dyad)	Vectorizing equality	-
+ (Dyad)	Vectorizing addition/string concatenation	-
- (Dyad)	Vectorizing subtraction	-
* (Dyad)	Vectorizing Multiplication/string repeat	-
/ (Dyad)	Vectorizing division	-
$ (Dyad)	Swap two items on the stack	-
% (Dyad)	Vectorizing modulus	-
~ (Dyad)	Remove items	-
L (Dyad)	Return the top operand, pop the second-to-top operand	-
R (Monad)	1-range, reverse for lists	Reverse 1-range, identity for lists
~ (Monad)	Remove the last item of the list	Remove the first item of the list
_ (Monad)	Pop the stack	Duplicate the stack
O (Monad)	Pops + Outputs TOS, disables implicit output. (exception to the monad rule)	-
"xyz" (Nilad)	Push "xyz"	Push "xyz" reversed
0-9 (Nilad)	Push the number formed by the construction	Push the negative of the number formed by the construction
I (Nilad)	Push the input (exception to the nilad rule)	-

I/O Specifications

There's implicit input, but you can also take explicit input via I.

The whole stack's content is joined and outputted at the end of the program.

Example programs

Is it odd or even?

R=+

Explanation

Assume the input = 3 right now.

R    1-range.              Push [1, 2, 3] (original function) and [3, 2, 1] (complement function)
 =   Vectorizing equality. Push [0, 1, 0]
  +  Sum the list.         Push 1          (If the stack only has one list item, DDuuaall reduces over the list by the dyadic operation)

Hello, World!

"Hello, World!"0+*+

Explanation

"Hello, World!"     String literal. Push "Hello, World!" (original) and "!dlroW, olleH" (complement)
               0    Number literal. Push 0 and -0 (aka push 2 0's)
                +   Add the two copies of 0.
                 *  Repeat the complement string by 0.
                  + Join the empty string by the original string.

Primalty Tester

RL~UI$L$%0+=+0

Explanation

Assume input = 4 here.

R                Range. [1, 2, 3, 4] and [4, 3, 2, 1]
 L               Left.  [1, 2, 3, 4]
  ~              Pop.   [1, 2, 3]    and [2, 3, 4]
   U             Intersect. [2, 3]
    I            Input. [2, 3], 4, -4
     $           Swap.  [2, 3], -4, 4
      L          Left.  [2, 3], 4
       $         Swap.  4, [2, 3]
        %        Mod.   [1, 0]
         0       Zero.  [1, 0], 0, 0
          +      Add.   [1, 0], 0
           =     Equals?[0, 1]
            +    Sum    1
             0   Output. OUT:1