Stackint is an esolang by User:PythonshellDebugwindow. Its only method of storage is, as its name suggests, a stack of integers.
Stackint uses an arbitrary-length stack of arbitrary-size signed integers.
The syntax of a program in Stackint is much the same as one in brainfuck; that is, it's made up of a series of characters, each one being its own command that takes no arguments and returns no value.
||Push that number to the stack|
||Push user input as a signed base-10 integer; if the integer is invalid, then 0 is pushed instead|
||Pop A and B, push A + B|
||Pop A and B, push A - B|
||Pop A and B, push A * B|
||Pop A and B, push A // B (floor division)|
||Pop A; if A is nonzero, then pop B and jump to the 0-based Bth character in the program (B stays on the stack if A is zero)|
||Duplicate the top of the stack|
||Duplicate the bottom of the stack (push the duplicate to the bottom)|
All other characters are ignored, and popping a number when the stack is empty returns 0. The language is case-insensitive.
At the end of the program, the stack is output as an array would be in Python; that is, surrounded by square brackets and separated by commas and spaces.
Output the ASCII values for Hello World as an array