Stackfest One Stack

Stacckfest One Stack is a variation of Stackfest made by User:Cordership. This esolang, however, has only one stack.

Syntax

Command	Definition
pop as [variable]	Pop top of stack and set it to a variable's value. Walrus operator.
push [blah blah blah]	Push a variable, a number, or a character/string (as its ASCII value(s)).
add	Pop values a and b, push the result of a+b.
subtract	Pop values a and b, push the result of b-a.
mult	Pop values a and b, push the result of a*b.
intdiv	Pop values a and b, push the result of b/a, rounded down. If a=0 then the result is the user input.
modulo	Pop values a and b, push the result of the integer division b/a.
exp	Pop values a and b, push the result of b^a.
outint	Pop top of stack and output it as integer.
outascii	Pop top of stack and output it as an ASCII character.
push inchar	Receive character from user and push it into the stack.
push inint	Receive integer from user and push it into the stack.
#	Comment.
null	Empty stack, equivalent to >>.
stack	Refers to the stack.
discard	Pop top of stack and discard.
[variable] = blah blah ...	Sets variable to a value.
"	Toggle stringmode.
reverse in [stackname]	Reverse the order of all the elements in the stack.
end	End program.
rand(a, b)	Gets a random integer n where a <= n <= b.

True-false booleans, control flow, and relational operators are the same as Python.

Programs

Hello, World!

push "!dlroW, olleH"
while stack != null:
    outascii

Looping counter

a = 1
while 1:
    for _ in range (a):
        push 42
    while stk != null:
        outint
    push a
    push 1
    add
    pop as a

Truth-machine

push inint
pop as t
if t == 0:
    push 0
    outint
    end
else:
    while 1:
        push 1
        outint

Fibonacci sequence

a = inint
b = 0
push 1
push b
for _ in range (a):
    pop as x
    pop as y
    push x
    push y
    pop as b
    push b
    add
    push b