You can output the top of the stack to stdout by using
Pops "Hello, World!" off the stack and outputs it
You can push strings to the stack by using
The stack now contains "Hello World!"
Characters are really stored as Strings on the stack, but they are a quick way to save a character when golfing.
'i 'h oo
Numbers are stored as doubles on the stack. You can just put the number you want to push it to the stack.
5 is pushed to the stack
You can't do double-digit numbers, though!
5s to the stack
You can use
A-Z as numbers, since numbers are parsed in Base 36.
You can manipulate the stack in a variety of ways. Here's a list of the most common operators:
;: pop the top of the stack and discard it
\: swap the top two values
@: put the third value of the stack on top
r: reverse the stack
l: push the length of the stack
o: pop the top of the stack and output it
i: get input and push it as a string
j: get input and push it as a base 10 number