Stack & Naming

def (definition operator)

Arguments < value: Value < name: Identifier

Modifies the LNT by setting the key-value pair name: value. This means that now the value of the identifier name is "defined" to be the value value, hence the name. Will overwrite any existing binding to name.

dup

Arguments < elmt: Value

Return value < elmt < elmt

Duplicates the topmost element on the stack.

globaldef (global definition operator)

The same as def, but always defines into the GNT.

pop (stack remove operator)

Arguments < any

Removes the topmost element from the stack and discards it.

swap (stack exchange operator)

Arguments < x < y

Return value < y < x

Exchanges the position of the two top-most elements on the stack.