qgram.jl

immutable QGramIterator{S, T <: Integer}
	s::S # grapheorstring
	l::Int # length of string
	q::T # length of q-grams
end

function Base.start(qgram::QGramIterator)
	(1, qgram.l < qgram.q ? endof(qgram.s) + 1 : chr2ind(qgram.s, qgram.q))
end
function Base.next(qgram::QGramIterator, state)
	istart, iend = state
	element = SubString(qgram.s, istart, iend)
	nextstate = nextind(qgram.s, istart), nextind(qgram.s, iend)
	element, nextstate
end
function Base.done(qgram::QGramIterator, state)
	istart, idend = state
	done(qgram.s, idend)
end
Base.eltype{S <: AbstractString, T}(qgram::QGramIterator{S, T}) = SubString{S}
Base.eltype{S, T}(qgram::QGramIterator{GraphemeIterator{S}, T}) = SubString{S}
Base.length(qgram::QGramIterator) = max(qgram.l - qgram.q + 1, 0)
function Base.collect(qgram::QGramIterator)
	x = Array(eltype(qgram), length(qgram))
	i = 0
	for q in qgram
		i += 1
		@inbounds x[i] = q
	end
	x
end
Base.sort(qgram::QGramIterator) = sort!(collect(qgram))