Stack Words

To get anything done in Smojo, you need to use its stack. There are a few built-in words you can use:

Word Action

DROP

Pops the top item off the stack and discards it. This item is lost and can't be retrieved.

DUP

Duplicates the top of the stack. For example,
1 DUP
ends up with
1 1
on the stack. Note that
DUP
does not re-create things on the stack; it merely duplicates pointers to things.

SWAP

Swaps the top two items on the stack. For example,
"Hello" "World" SWAP
ends up with
"World" "Hello"
on the stack.

Word	Action
DROP	Pops the top item off the stack and discards it. This item is lost and can't be retrieved.
DUP	Duplicates the top of the stack. For example, 1 DUP ends up with 1 1 on the stack. Note that DUP does not re-create things on the stack; it merely duplicates pointers to things.
SWAP	Swaps the top two items on the stack. For example, "Hello" "World" SWAP ends up with "World" "Hello" on the stack.

Quiz

Question 1

Write a word called

DOUBLE

that puts double the number on the top of the stack. For example,

23 double .

should display 46

		: double dup +. ;

Question 2

Write a word called

1/

that puts reciprocal of the number on the top of the stack. For example,

5 1/ .

should display 0.2

		: 1/ 1 swap /. ;

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