Matterhorn.Types.NonemptyStack

Documentation

data NonemptyStack a

A stack that always has at least one value on it.

Instances

Show a => Show (NonemptyStack a)

Defined in Matterhorn.Types.NonemptyStack

Methods

showsPrec :: Int -> NonemptyStack a -> ShowS

show :: NonemptyStack a -> String

showList :: [NonemptyStack a] -> ShowS

newStack :: a -> NonemptyStack a

Make a new stack with the specified value at the bottom.

push :: a -> NonemptyStack a -> NonemptyStack a

Push the specified value on to the stack.

pop :: NonemptyStack a -> (NonemptyStack a, Maybe a)

Pop the top value from the stack. If a value could be popped, return the new stack and the value that was popped. Otherwise return the stack unmodified with Nothing to indicate that nothing was popped.

top :: NonemptyStack a -> a

Return the value on the top of the stack. Always succeeds since the stack is guaranteed to be non-empty.

stackToList :: NonemptyStack a -> [a]

Return the stack as a list, topmost element first.