StatefulIterators

A stream-like wrapper around iterable objects (it's spelt "Stateful" with a trailing lowercase L, and then "Iterators" with a leading, uppercase I).

Example

This makes the usual iter-related methods "stateful" - they don't "reset" to the start of the collection on each use:

julia> using StatefulIterators

julia> s = StatefulIterator([1,2,3,4,5])
StatefulIterators.ArrayIterator{Int64}([1,2,3,4,5],1)

julia> collect(take(s, 3))
3-element Array{Any,1}:
 1
 2
 3

julia> collect(take(s, 3))
2-element Array{Any,1}:
 4
 5

Read Methods

The iterators also support read methods similar to streams.

julia> s = StatefulIterator([0x1, 0x2, 0x3, 0x4])
StatefulIterators.ArrayIterator{UInt8}(UInt8[0x01,0x02,0x03,0x04],1)

julia> read(s, Int16, 2)
2-element Array{Int16,1}:
  513
 1027

Note that type conversion only works for iterators over typed arrays:

julia> StatefulIterator("abc")
StatefulIterators.IterIterator("abc",1)

julia> collect(take(StatefulIterator("abc"), 2))
2-element Array{Any,1}:
 'a'
 'b'

julia> read(StatefulIterator("abc"), UInt8)
ERROR: MethodError: `*` has no method matching *(::Type{UInt8})
Closest candidates are:
  *(::Any, ::Any, ::Any, ::Any...)
 in read at /home/andrew/.julia/v0.4/StatefulIterators/src/StatefulIterators.jl:48

(I have no idea where that specific error originates, but this fails in general because we only "know" the underlying type for arrays).

Warnings

This is much less efficient than using normal iterators (ref).