Iterator interface

.gitignore

@@ -6,3 +6,4 @@ docs/build/
 docs/site/
 benchmark/.results/*
 benchmark/.tune.jld
+*.cov

src/LightGraphs.jl

@@ -18,7 +18,7 @@ import SparseArrays: blockdiag, sparse
 import Base: write, ==, <, *, ≈, convert, isless, issubset, union, intersect,
             reverse, reverse!, isassigned, getindex, setindex!, show,
             print, copy, in, sum, size, eltype, length, ndims, transpose,
-            ctranspose, join, start, next, done, eltype, get, Pair, Tuple, zero
+            ctranspose, join, iterate, eltype, get, Pair, Tuple, zero
 
 
 export

src/SimpleGraphs/SimpleGraphs.jl

@@ -4,7 +4,7 @@ using SparseArrays
 using LinearAlgebra
 
 import Base:
-    eltype, show, ==, Pair, Tuple, copy, length, start, next, done, issubset, zero, in
+    eltype, show, ==, Pair, Tuple, copy, length, issubset, zero, in, iterate
 
 import LightGraphs:
     _NI, _insert_and_dedup!, AbstractGraph, AbstractEdge, AbstractEdgeIter,

src/SimpleGraphs/simpleedgeiter.jl

@@ -46,10 +46,17 @@ function edge_next(g::AbstractSimpleGraph,
     return e, SimpleEdgeIterState(zero(T), 1)
 end
 
-start(eit::SimpleEdgeIter) = edge_start(eit.g)
-done(eit::SimpleEdgeIter, state::SimpleEdgeIterState{T}) where T = state.s == zero(T)
+function iterate(eit::SimpleEdgeIter{G}) where {G<:AbstractSimpleGraph}
+    state = edge_start(eit.g)
+    return iterate(eit, state)
+end
+
+function iterate(eit::SimpleEdgeIter{G}, state::SimpleEdgeIterState{T}) where {T,G<:AbstractSimpleGraph{T}}
+    state.s == zero(T) && return nothing
+    return edge_next(eit.g, state)
+end
+
 length(eit::SimpleEdgeIter) = ne(eit.g)
-next(eit::SimpleEdgeIter, state::SimpleEdgeIterState) = edge_next(eit.g, state)
 
 function _isequal(e1::SimpleEdgeIter, e2)
     k = 0

test/simplegraphs/simpleedgeiter.jl

@@ -2,7 +2,9 @@
     ga = @inferred(SimpleGraph(10, 20; seed=1))
     gb = @inferred(SimpleGraph(10, 20; seed=1))
     @test sprint(show, edges(ga)) == "SimpleEdgeIter 20"
-    @test sprint(show, start(edges(ga))) == "SimpleEdgeIterState [1, 1]"
+    # note: we don't get the first iterator state,
+    #since iterate returns the state after taking the first value
+    @test sprint(show, iterate(edges(ga))[2]) == "SimpleEdgeIterState [1, 2]"
 
     @test length(collect(edges(Graph(0, 0)))) == 0
 
@@ -46,10 +48,11 @@
     end
 
     eit = edges(ga)
-    es = @inferred(start(eit))
+    # @inferred not valid for new interface anymore (return type is a Union)
+    es = iterate(eit)[2]
 
-    @test es.s == 2
-    @test es.di == 1
+    @test es.s == 3
+    @test es.di == 2
 
     @test [e for e in eit] == [Edge(2, 3), Edge(3, 10), Edge(5, 10)]
 
@@ -73,10 +76,10 @@
     end
 
     eit = @inferred(edges(ga))
-    es = @inferred(start(eit))
+    es = iterate(eit)[2]
 
     @test es.s == 3
-    @test es.di == 1
+    @test es.di == 2
 
     @test [e for e in eit] == [
       SimpleEdge(3, 2), SimpleEdge(3, 10),