initial changes to the way tags are stored

src/queries.jl

@@ -5,8 +5,10 @@ Assign a tag to a slot in a register.
 It returns the list of all currently present tags for that register.
 
 See also: [`query`](@ref), [`untag!`](@ref)"""
-function tag!(ref::RegRef, tag::Tag)
-    push!(ref.reg.tags[ref.idx], tag)
+function tag!(ref::RegRef, tag::Tag, time=nothing)
+    push!(ref.reg.tags, tag)
+    push!(ref.tag_idx, size(ref.reg.tags)[1])
+    push!(ref.tag_time, time)
 end
 
 tag!(ref, tag) = tag!(ref, Tag(tag))
@@ -23,7 +25,14 @@ See also: [`query`](@ref), [`tag!`](@ref)
 function untag!(ref::RegRef, tag::Tag) # TODO rather slow implementation. See issue #74
     tags = ref.reg.tags[ref.idx]
     i = findfirst(==(tag), tags)
-    isnothing(i) ? throw(KeyError(tag)) : deleteat!(tags, i) # TODO make sure there is a clear error message
+    if isnothing(i)
+        throw(KeyError(tag))  # TODO make sure there is a clear error message
+    else
+        idx = findfirst(==(i), ref.tag_idx) # everytime a tag is untagged or `querydelete!` is called the `idx` is removed from ref.tag_idx, so we won't have any duplicates
+        deleteat!(tags, i)
+        deleteat!(ref.tag_idx, idx)
+        deleteat!(ref.tag_time, idx)
+    end
 end
 
 

src/states_registers.jl

@@ -20,12 +20,12 @@ struct Register # TODO better type description
     stateindices::Vector{Int}
     accesstimes::Vector{Float64} # TODO do not hardcode the type
     locks::Vector{Any}
-    tags::Vector{Vector{Tag}} # TODO this is a rather inefficient way to store tags, but at least it provides a FIFO ordering; see issue #74
+    tags::Vector{Tag} # TODO this is a rather inefficient way to store tags, but at least it provides a FIFO ordering; see issue #74
 end
 
 function Register(traits, reprs, bg, sr, si, at)
     env = ConcurrentSim.Simulation()
-    Register(traits, reprs, bg, sr, si, at, [ConcurrentSim.Resource(env) for _ in traits], [Vector{Tag}() for _ in traits])
+    Register(traits, reprs, bg, sr, si, at, [ConcurrentSim.Resource(env) for _ in traits], Vector{Tag}())
 end
 Register(traits,reprs,bg,sr,si) = Register(traits,reprs,bg,sr,si,zeros(length(traits)))
 Register(traits,reprs,bg) = Register(traits,reprs,bg,fill(nothing,length(traits)),zeros(Int,length(traits)),zeros(length(traits)))
@@ -49,6 +49,11 @@ julia> r = Register(2)
 struct RegRef
     reg::Register
     idx::Int
+    tag_idx::Vector{Int}
+    tag_time::Vector{Float64}
 end
 
+function RegRef(r::Register, idx::Int)
+    RegRef(r, idx, [], [])
+end
 #Base.:(==)(r1::Register, r2::Register) =