Modern Array ArrayIterator

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ArrayIterator

Holds a position in an Array; steps with IsValid, Value and MoveNext.

Syntax

ArrayIterator( of T )

Notes

• The iterator protocol -- IsValid, Value, MoveNext -- which is what for each is rewritten into. Ordinary code names the type only when the loop has to stop early, resume, or interleave with another.
• Value( ) returns byref, so for each byref v in a can modify elements in place.
• It holds a pointer to the array, not a copy -- an iterator is created per loop and must not deep-copy the container.
• It is invalidated by anything that reallocates the storage, which a Push past the capacity does.

Examples

#import "std/containers"
using containers

dim v as Array( of int32 )
v.Push( 1 ) : v.Push( 2 ) : v.Push( 3 )

dim it as ArrayIterator( of int32 ) = v.GetIterator( )
while it.IsValid( )
    print it.Value( )        '' 1 / 2 / 3
    it.MoveNext( )
wend

'' Value( ) is byref, so it assigns through
dim jt as ArrayIterator( of int32 ) = v.GetIterator( )
jt.Value( ) = 99
print v[ 0 ]                 '' 99

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Library: Array Container
Category: Array
Documented under: Members