.TH "Stack" 3o source: 2019-01-25 OCamldoc "OCaml library"
.SH NAME
Stack \- Last-in first-out stacks.
.SH Module
Module   Stack
.SH Documentation
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Module
.BI "Stack"
 : 
.B sig  end

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Last\-in first\-out stacks\&.
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This module implements stacks (LIFOs), with in\-place modification\&.

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.I type 
.B 'a
.I t 

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The type of stacks containing elements of type 
.B \&'a
\&.

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.I exception Empty 

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Raised when 
.B Stack\&.pop
or 
.B Stack\&.top
is applied to an empty stack\&.

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.I val create 
: 
.B unit -> 'a t
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Return a new stack, initially empty\&.

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.I val push 
: 
.B 'a -> 'a t -> unit
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.B push x s
adds the element 
.B x
at the top of stack 
.B s
\&.

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.I val pop 
: 
.B 'a t -> 'a
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.B pop s
removes and returns the topmost element in stack 
.B s
,
or raises 
.B Stack\&.Empty
if the stack is empty\&.

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.I val top 
: 
.B 'a t -> 'a
.sp

.B top s
returns the topmost element in stack 
.B s
,
or raises 
.B Stack\&.Empty
if the stack is empty\&.

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.I val clear 
: 
.B 'a t -> unit
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Discard all elements from a stack\&.

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.I val copy 
: 
.B 'a t -> 'a t
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Return a copy of the given stack\&.

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.I val is_empty 
: 
.B 'a t -> bool
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Return 
.B true
if the given stack is empty, 
.B false
otherwise\&.

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.I val length 
: 
.B 'a t -> int
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Return the number of elements in a stack\&. Time complexity O(1)

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.I val iter 
: 
.B ('a -> unit) -> 'a t -> unit
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.B iter f s
applies 
.B f
in turn to all elements of 
.B s
,
from the element at the top of the stack to the element at the
bottom of the stack\&. The stack itself is unchanged\&.

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.I val fold 
: 
.B ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b
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.B fold f accu s
is 
.B (f (\&.\&.\&. (f (f accu x1) x2) \&.\&.\&.) xn)
where 
.B x1
is the top of the stack, 
.B x2
the second element,
and 
.B xn
the bottom element\&. The stack is unchanged\&.

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.B "Since"
4.03

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