
Copyright 2008  2010 Tony Morris, Runar Bjarnason, Tom Adams, Brad Clow, Ricky Clarkson, Nick Partridge, Jason Zaugg This software is released under an open source BSD licence. 

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java.lang.Object fj.data.Zipper<A>
public final class Zipper<A>
Provides a pointed stream, which is a nonempty zipperlike stream structure that tracks an index (focus) position in a stream. Focus can be moved forward and backwards through the stream, elements can be inserted before or after the focused position, and the focused item can be deleted.
Based on the pointedlist library by Jeff Wheeler.
Method Summary  

boolean 
atEnd()
Returns whether the focus is on the last element. 

boolean 
atStart()
Returns whether the focus is on the first element. 


cobind(F<Zipper<A>,B> f)
Maps over variations of this zipper, such that the given function is applied to each variation (comonad pattern). 

Zipper<A> 
cycleNext()
Move the focus to the next element. 

Zipper<A> 
cyclePrevious()
Move the focus to the previous element. 

Option<Zipper<A>> 
deleteLeft()
Possibly deletes the element at the focus, then moves the element on the left into focus. 

Option<Zipper<A>> 
deleteLeftCycle()
Possibly deletes the element at the focus, then move the element on the left into focus. 

Zipper<A> 
deleteOthers()
Deletes all elements in the zipper except the focus. 

Option<Zipper<A>> 
deleteRight()
Possibly deletes the element at the focus, then moves the element on the right into focus. 

Option<Zipper<A>> 
deleteRightCycle()
Possibly deletes the element at the focus, then move the element on the right into focus. 

static

eq(Equal<A> e)
An Equal instance for Zippers. 

Option<Zipper<A>> 
find(F<A,java.lang.Boolean> p)
Moves the focus to the element matching the given predicate, if present. 

A 
focus()
Returns the focus element of this zipper. 


foldRight(F<A,F<B,B>> f,
B z)
Performs a rightfold reduction across this zipper. 

static

fromStream(Stream<A> a)
Possibly create a zipper if the provided stream has at least one element, otherwise None. 

static

fromStreamEnd(Stream<A> a)
Possibly create a zipper if the provided stream has at least one element, otherwise None. 

int 
index()
Returns the index of the focus. 

Zipper<A> 
insertLeft(A a)
Inserts an element to the left of the focus, then moves the focus to the new element. 

Zipper<A> 
insertRight(A a)
Inserts an element to the right of the focus, then moves the focus to the new element. 

java.util.Iterator<Zipper<A>> 
iterator()
Returns an iterator of all the positions of this Zipper, starting from the leftmost position. 

Stream<A> 
lefts()
Returns a Stream of the elements to the left of focus. 

int 
length()
Returns the length of this zipper. 


map(F<A,B> f)
Maps the given function across the elements of this zipper (covariant functor pattern). 

static

move()
A firstclass version of the move function. 

Option<Zipper<A>> 
move(int n)
Move the focus to the specified index. 

static

next_()
Firstclass version of the next() function. 

Option<Zipper<A>> 
next()
Possibly moves the focus to the next element in the list. 

static

ord(Ord<A> o)
An Ord instance for Zippers. 

static

p_()
A firstclass function that yields the product3 representation of a given Zipper. 

P3<Stream<A>,A,Stream<A>> 
p()
Returns the product3 representation of this Zipper. 

Zipper<Zipper<A>> 
positions()
Creates a zipper of variations of this zipper, in which each element is focused, with this zipper as the focus of the zipper of zippers (comonad pattern). 

static

previous_()
Firstclass version of the previous() function. 

Option<Zipper<A>> 
previous()
Possibly moves the focus to the previous element in the list. 

Zipper<A> 
replace(A a)
Replaces the element in focus with the given element. 

Stream<A> 
rights()
Returns a Stream of the elements to the right of focus. 

static

show(Show<A> s)
A Show instance for Zippers. 

static

single(A a)
Creates a new zipper with a single element. 

Stream<A> 
toStream()
Returns the Stream representation of this zipper. 

Zipper<A> 
tryNext()
Attempts to move the focus to the next element, or throws an error if there are no more elements. 

Zipper<A> 
tryPrevious()
Attempts to move the focus to the previous element, or throws an error if there are no more elements. 

static

zipper()
Firstclass constructor of zippers. 

static

zipper(P3<Stream<A>,A,Stream<A>> p)
Creates a new Zipper from the given triple. 

static

zipper(Stream<A> left,
A focus,
Stream<A> right)
Creates a new Zipper with the given streams before and after the focus, and the given focused item. 


zipWith(Zipper<B> bs,
F<A,F<B,C>> f)
Zips this Zipper with another, applying the given function lockstep over both zippers in both directions. 


zipWith(Zipper<B> bs,
F2<A,B,C> f)
Zips this Zipper with another, applying the given function lockstep over both zippers in both directions. 

Zipper<P2<A,java.lang.Boolean>> 
zipWithFocus()
Zips the elements of this zipper with a boolean that indicates whether that element has focus. 
Methods inherited from class java.lang.Object 

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
Method Detail 

public static <A> Zipper<A> zipper(Stream<A> left, A focus, Stream<A> right)
left
 The stream of elements before the focus.focus
 The element under focus.right
 The stream of elements after the focus.
public static <A> Zipper<A> zipper(P3<Stream<A>,A,Stream<A>> p)
p
 A triple of the elements before the focus, the focus element, and the elements after the focus,
respectively.
public static <A> F3<Stream<A>,A,Stream<A>,Zipper<A>> zipper()
public P3<Stream<A>,A,Stream<A>> p()
public static <A> F<Zipper<A>,P3<Stream<A>,A,Stream<A>>> p_()
public static <A> Ord<Zipper<A>> ord(Ord<A> o)
o
 An Ord instance for the element type.
public static <A> Equal<Zipper<A>> eq(Equal<A> e)
e
 An Equal instance for the element type.
public static <A> Show<Zipper<A>> show(Show<A> s)
s
 A Show instance for the element type.
public <B> Zipper<B> map(F<A,B> f)
f
 A function to map across this zipper.
public <B> B foldRight(F<A,F<B,B>> f, B z)
f
 The function to apply on each element of this zipper.z
 The beginning value to start the application from.
public static <A> Zipper<A> single(A a)
a
 The focus element of the new zipper.
public static <A> Option<Zipper<A>> fromStream(Stream<A> a)
a
 The stream from which to create a zipper.
public static <A> Option<Zipper<A>> fromStreamEnd(Stream<A> a)
a
 The stream from which to create a zipper.
public A focus()
public Option<Zipper<A>> next()
public Zipper<A> tryNext()
public Option<Zipper<A>> previous()
public Zipper<A> tryPrevious()
public static <A> F<Zipper<A>,Option<Zipper<A>>> next_()
public static <A> F<Zipper<A>,Option<Zipper<A>>> previous_()
public Zipper<A> insertLeft(A a)
a
 A new element to insert into this zipper.
public Zipper<A> insertRight(A a)
a
 A new element to insert into this zipper.
public Option<Zipper<A>> deleteLeft()
public Option<Zipper<A>> deleteRight()
public Zipper<A> deleteOthers()
public int length()
public boolean atStart()
public boolean atEnd()
public Zipper<Zipper<A>> positions()
public <B> Zipper<B> cobind(F<Zipper<A>,B> f)
f
 The comonadic function to apply for each variation of this zipper.
public Zipper<P2<A,java.lang.Boolean>> zipWithFocus()
public Option<Zipper<A>> move(int n)
n
 The index to which to move the focus.
public static <A> F<java.lang.Integer,F<Zipper<A>,Option<Zipper<A>>>> move()
public Option<Zipper<A>> find(F<A,java.lang.Boolean> p)
p
 A predicate to match.
public int index()
public Zipper<A> cycleNext()
public Zipper<A> cyclePrevious()
public Option<Zipper<A>> deleteLeftCycle()
public Option<Zipper<A>> deleteRightCycle()
public Zipper<A> replace(A a)
a
 An element to replace the focused element with.
public Stream<A> toStream()
public Stream<A> lefts()
public Stream<A> rights()
public <B,C> Zipper<C> zipWith(Zipper<B> bs, F2<A,B,C> f)
bs
 A Zipper to zip this one with.f
 A function with which to zip together the two Zippers.
public <B,C> Zipper<C> zipWith(Zipper<B> bs, F<A,F<B,C>> f)
bs
 A Zipper to zip this one with.f
 A function with which to zip together the two Zippers.
public java.util.Iterator<Zipper<A>> iterator()
iterator
in interface java.lang.Iterable<Zipper<A>>

Copyright 2008  2010 Tony Morris, Runar Bjarnason, Tom Adams, Brad Clow, Ricky Clarkson, Nick Partridge, Jason Zaugg This software is released under an open source BSD licence. 

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