better docs for lists and deques (#10390)
* better docs: lists * better docs: deques
This commit is contained in:
Miran
Andreas Rumpf
parent
9a003bae06
commit
4bea8dd674
2 changed files with 757 additions and 78 deletions
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@ -20,41 +20,59 @@
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## access, unless your program logic guarantees it indirectly.
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##
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## .. code-block:: Nim
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## proc foo(a, b: Positive) = # assume random positive values for `a` and `b`
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## var deq = initDeque[int]() # initializes the object
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## for i in 1 ..< a: deq.addLast i # populates the deque
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## import deques
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##
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## if b < deq.len: # checking before indexed access
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## echo "The element at index position ", b, " is ", deq[b]
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## var a = initDeque[int]()
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##
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## # The following two lines don't need any checking on access due to the
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## # logic of the program, but that would not be the case if `a` could be 0.
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## assert deq.peekFirst == 1
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## assert deq.peekLast == a
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## doAssertRaises(IndexError, echo a[0])
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##
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## while deq.len > 0: # checking if the deque is empty
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## echo deq.popLast()
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## for i in 1 .. 5:
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## a.addLast(10*i)
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## assert $a == "[10, 20, 30, 40, 50]"
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##
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## Note: For inter thread communication use
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## a `Channel <channels.html>`_ instead.
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## assert a.peekFirst == 10
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## assert a.peekLast == 50
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## assert len(a) == 5
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##
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## assert a.popFirst == 10
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## assert a.popLast == 50
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## assert len(a) == 3
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##
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## a.addFirst(11)
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## a.addFirst(22)
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## a.addFirst(33)
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## assert $a == "[33, 22, 11, 20, 30, 40]"
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##
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## a.shrink(fromFirst = 1, fromLast = 2)
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## assert $a == "[22, 11, 20]"
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##
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##
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## **See also:**
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## * `lists module <lists.html>`_ for singly and doubly linked lists and rings
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## * `channels module <channels.html>`_ for inter-thread communication
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import math, typetraits
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type
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Deque*[T] = object
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## A double-ended queue backed with a ringed seq buffer.
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##
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## To initialize an empty deque use `initDeque proc <#initDeque,int>`_.
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data: seq[T]
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head, tail, count, mask: int
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proc initDeque*[T](initialSize: int = 4): Deque[T] =
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## Create a new deque.
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## Optionally, the initial capacity can be reserved via `initialSize` as a
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## performance optimization. The length of a newly created deque will still
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## be 0.
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## Create a new empty deque.
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##
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## `initialSize` needs to be a power of two. If you need to accept runtime
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## values for this you could use the ``nextPowerOfTwo`` proc from the
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## `math <math.html>`_ module.
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## Optionally, the initial capacity can be reserved via `initialSize`
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## as a performance optimization.
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## The length of a newly created deque will still be 0.
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##
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## ``initialSize`` must be a power of two (default: 4).
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## If you need to accept runtime values for this you could use the
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## `nextPowerOfTwo proc<math.html#nextPowerOfTwo,int>`_ from the
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## `math module<math.html>`_.
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assert isPowerOfTwo(initialSize)
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result.mask = initialSize-1
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newSeq(result.data, initialSize)
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@ -75,45 +93,128 @@ template xBoundsCheck(deq, i) =
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if unlikely(i >= deq.count): # x < deq.low is taken care by the Natural parameter
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raise newException(IndexError,
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"Out of bounds: " & $i & " > " & $(deq.count - 1))
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if unlikely(i < 0): # when used with BackwardsIndex
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raise newException(IndexError,
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"Out of bounds: " & $i & " < 0")
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proc `[]`*[T](deq: Deque[T], i: Natural) : T {.inline.} =
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## Access the i-th element of `deq` by order from first to last.
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## deq[0] is the first, deq[^1] is the last.
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## Access the i-th element of `deq`.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert a[0] == 10
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assert a[3] == 40
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doAssertRaises(IndexError, echo a[8])
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xBoundsCheck(deq, i)
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return deq.data[(deq.head + i) and deq.mask]
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proc `[]`*[T](deq: var Deque[T], i: Natural): var T {.inline.} =
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## Access the i-th element of `deq` and returns a mutable
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## Access the i-th element of `deq` and return a mutable
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## reference to it.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert a[0] == 10
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assert a[3] == 40
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doAssertRaises(IndexError, echo a[8])
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xBoundsCheck(deq, i)
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return deq.data[(deq.head + i) and deq.mask]
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proc `[]=`*[T](deq: var Deque[T], i: Natural, val : T) {.inline.} =
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## Change the i-th element of `deq`.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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a[0] = 99
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a[3] = 66
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assert $a == "[99, 20, 30, 66, 50]"
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xBoundsCheck(deq, i)
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deq.data[(deq.head + i) and deq.mask] = val
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proc `[]`*[T](deq: var Deque[T], i: BackwardsIndex): var T {.inline.} =
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## Access the backwards indexed i-th element.
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return deq[deq.len - int(i)]
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proc `[]`*[T](deq: Deque[T], i: BackwardsIndex): T {.inline.} =
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## Access the backwards indexed i-th element.
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##
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## `deq[^1]` is the last element.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert a[^1] == 50
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assert a[^4] == 20
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doAssertRaises(IndexError, echo a[^9])
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xBoundsCheck(deq, deq.len - int(i))
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return deq[deq.len - int(i)]
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proc `[]`*[T](deq: var Deque[T], i: BackwardsIndex): var T {.inline.} =
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## Access the backwards indexed i-th element.
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##
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## `deq[^1]` is the last element.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert a[^1] == 50
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assert a[^4] == 20
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doAssertRaises(IndexError, echo a[^9])
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xBoundsCheck(deq, deq.len - int(i))
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return deq[deq.len - int(i)]
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proc `[]=`*[T](deq: var Deque[T], i: BackwardsIndex, x: T) {.inline.} =
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## Change the backwards indexed i-th element.
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##
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## `deq[^1]` is the last element.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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a[^1] = 99
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a[^3] = 77
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assert $a == "[10, 20, 77, 40, 99]"
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xBoundsCheck(deq, deq.len - int(i))
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deq[deq.len - int(i)] = x
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iterator items*[T](deq: Deque[T]): T =
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## Yield every element of `deq`.
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##
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## **Examples:**
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##
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## .. code-block::
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## var a = initDeque[int]()
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## for i in 1 .. 3:
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## a.addLast(10*i)
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##
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## for x in a: # the same as: for x in items(a):
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## echo x
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##
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## # 10
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## # 20
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## # 30
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##
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var i = deq.head
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for c in 0 ..< deq.count:
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yield deq.data[i]
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i = (i + 1) and deq.mask
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iterator mitems*[T](deq: var Deque[T]): var T =
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## Yield every element of `deq`.
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## Yield every element of `deq`, which can be modified.
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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for x in mitems(a):
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x = 5*x - 1
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assert $a == "[49, 99, 149, 199, 249]"
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var i = deq.head
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for c in 0 ..< deq.count:
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yield deq.data[i]
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@ -121,18 +222,35 @@ iterator mitems*[T](deq: var Deque[T]): var T =
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iterator pairs*[T](deq: Deque[T]): tuple[key: int, val: T] =
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## Yield every (position, value) of `deq`.
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##
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## **Examples:**
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##
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## .. code-block::
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## var a = initDeque[int]()
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## for i in 1 .. 3:
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## a.addLast(10*i)
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##
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## for k, v in pairs(a):
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## echo "key: ", k, ", value: ", v
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##
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## # key: 0, value: 10
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## # key: 1, value: 20
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## # key: 2, value: 30
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##
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var i = deq.head
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for c in 0 ..< deq.count:
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yield (c, deq.data[i])
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i = (i + 1) and deq.mask
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proc contains*[T](deq: Deque[T], item: T): bool {.inline.} =
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## Return true if `item` is in `deq` or false if not found. Usually used
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## via the ``in`` operator. It is the equivalent of ``deq.find(item) >= 0``.
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## Return true if `item` is in `deq` or false if not found.
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##
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## Usually used via the ``in`` operator.
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## It is the equivalent of ``deq.find(item) >= 0``.
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##
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## .. code-block:: Nim
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## if x in q:
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## assert q.contains x
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## assert q.contains(x)
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for e in deq:
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if e == item: return true
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return false
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@ -150,6 +268,19 @@ proc expandIfNeeded[T](deq: var Deque[T]) =
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proc addFirst*[T](deq: var Deque[T], item: T) =
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## Add an `item` to the beginning of the `deq`.
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##
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## See also:
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## * `addLast proc <#addLast,Deque[T],T>`_
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## * `peekFirst proc <#peekFirst,Deque[T]>`_
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## * `peekLast proc <#peekLast,Deque[T]>`_
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## * `popFirst proc <#popFirst,Deque[T]>`_
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## * `popLast proc <#popLast,Deque[T]>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addFirst(10*i)
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assert $a == "[50, 40, 30, 20, 10]"
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expandIfNeeded(deq)
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inc deq.count
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deq.head = (deq.head - 1) and deq.mask
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@ -157,6 +288,19 @@ proc addFirst*[T](deq: var Deque[T], item: T) =
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proc addLast*[T](deq: var Deque[T], item: T) =
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## Add an `item` to the end of the `deq`.
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##
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## See also:
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## * `addFirst proc <#addFirst,Deque[T],T>`_
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## * `peekFirst proc <#peekFirst,Deque[T]>`_
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## * `peekLast proc <#peekLast,Deque[T]>`_
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## * `popFirst proc <#popFirst,Deque[T]>`_
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## * `popLast proc <#popLast,Deque[T]>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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expandIfNeeded(deq)
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inc deq.count
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deq.data[deq.tail] = item
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@ -164,11 +308,41 @@ proc addLast*[T](deq: var Deque[T], item: T) =
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proc peekFirst*[T](deq: Deque[T]): T {.inline.}=
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## Returns the first element of `deq`, but does not remove it from the deque.
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##
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## See also:
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## * `addFirst proc <#addFirst,Deque[T],T>`_
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## * `addLast proc <#addLast,Deque[T],T>`_
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## * `peekLast proc <#peekLast,Deque[T]>`_
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## * `popFirst proc <#popFirst,Deque[T]>`_
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## * `popLast proc <#popLast,Deque[T]>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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assert a.peekFirst == 10
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assert len(a) == 5
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emptyCheck(deq)
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result = deq.data[deq.head]
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proc peekLast*[T](deq: Deque[T]): T {.inline.} =
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## Returns the last element of `deq`, but does not remove it from the deque.
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##
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## See also:
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## * `addFirst proc <#addFirst,Deque[T],T>`_
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## * `addLast proc <#addLast,Deque[T],T>`_
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## * `peekFirst proc <#peekFirst,Deque[T]>`_
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## * `popFirst proc <#popFirst,Deque[T]>`_
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## * `popLast proc <#popLast,Deque[T]>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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assert a.peekLast == 50
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assert len(a) == 5
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emptyCheck(deq)
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result = deq.data[(deq.tail - 1) and deq.mask]
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@ -177,6 +351,23 @@ template destroy(x: untyped) =
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proc popFirst*[T](deq: var Deque[T]): T {.inline, discardable.} =
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## Remove and returns the first element of the `deq`.
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##
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## See also:
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## * `addFirst proc <#addFirst,Deque[T],T>`_
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## * `addLast proc <#addLast,Deque[T],T>`_
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## * `peekFirst proc <#peekFirst,Deque[T]>`_
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## * `peekLast proc <#peekLast,Deque[T]>`_
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## * `popLast proc <#popLast,Deque[T]>`_
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## * `clear proc <#clear,Deque[T]>`_
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## * `shrink proc <#shrink,Deque[T],int,int>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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assert a.popFirst == 10
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assert $a == "[20, 30, 40, 50]"
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emptyCheck(deq)
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dec deq.count
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result = deq.data[deq.head]
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@ -185,6 +376,23 @@ proc popFirst*[T](deq: var Deque[T]): T {.inline, discardable.} =
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proc popLast*[T](deq: var Deque[T]): T {.inline, discardable.} =
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## Remove and returns the last element of the `deq`.
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##
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## See also:
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## * `addFirst proc <#addFirst,Deque[T],T>`_
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## * `addLast proc <#addLast,Deque[T],T>`_
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## * `peekFirst proc <#peekFirst,Deque[T]>`_
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## * `peekLast proc <#peekLast,Deque[T]>`_
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## * `popFirst proc <#popFirst,Deque[T]>`_
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## * `clear proc <#clear,Deque[T]>`_
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## * `shrink proc <#shrink,Deque[T],int,int>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addLast(10*i)
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assert $a == "[10, 20, 30, 40, 50]"
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assert a.popLast == 50
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assert $a == "[10, 20, 30, 40]"
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emptyCheck(deq)
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dec deq.count
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deq.tail = (deq.tail - 1) and deq.mask
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@ -193,17 +401,39 @@ proc popLast*[T](deq: var Deque[T]): T {.inline, discardable.} =
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proc clear*[T](deq: var Deque[T]) {.inline.} =
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## Resets the deque so that it is empty.
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##
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## See also:
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## * `clear proc <#clear,Deque[T]>`_
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## * `shrink proc <#shrink,Deque[T],int,int>`_
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runnableExamples:
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var a = initDeque[int]()
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for i in 1 .. 5:
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a.addFirst(10*i)
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assert $a == "[50, 40, 30, 20, 10]"
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clear(a)
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assert len(a) == 0
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for el in mitems(deq): destroy(el)
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deq.count = 0
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deq.tail = deq.head
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proc shrink*[T](deq: var Deque[T], fromFirst = 0, fromLast = 0) =
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## Remove `fromFirst` elements from the front of the deque and
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## `fromLast` elements from the back. If the supplied number of
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## elements exceeds the total number of elements in the deque,
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## the deque will remain empty.
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## `fromLast` elements from the back.
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##
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## Any user defined destructors
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## If the supplied number of elements exceeds the total number of elements
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## in the deque, the deque will remain empty.
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##
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## See also:
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## * `clear proc <#clear,Deque[T]>`_
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runnableExamples:
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var a = initDeque[int]()
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||||
for i in 1 .. 5:
|
||||
a.addFirst(10*i)
|
||||
assert $a == "[50, 40, 30, 20, 10]"
|
||||
a.shrink(fromFirst = 2, fromLast = 1)
|
||||
assert $a == "[30, 20]"
|
||||
|
||||
if fromFirst + fromLast > deq.count:
|
||||
clear(deq)
|
||||
return
|
||||
|
|
@ -226,6 +456,8 @@ proc `$`*[T](deq: Deque[T]): string =
|
|||
result.addQuoted(x)
|
||||
result.add("]")
|
||||
|
||||
|
||||
|
||||
when isMainModule:
|
||||
var deq = initDeque[int](1)
|
||||
deq.addLast(4)
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue