Widget signal autosync

Adds `Reactive.map`s to keep most Widgets in better sync with their signals, i.e. push!ing to most widget's signals will update the widget's state too
Improves handling of `signal` and `value` fields being set on widget creation
Fix rare bug when backbone updates for options have only the label and no value field
Adds notebook for manual testing

REQUIRE

@@ -2,4 +2,4 @@ julia 0.4
 JSON
 Compat 0.8.0
 Reactive 0.3
-DataStructures 0.2.10
+DataStructures

src/IJulia/handle_msg.jl

@@ -21,11 +21,12 @@ function handle_msg{T}(w::Button{T}, msg)
 end
 
 function handle_msg{view}(w::Options{view}, msg)
-        if msg.content["data"]["method"] == "backbone"
+        if msg.content["data"]["method"] == "backbone" &&
+                haskey(msg.content["data"]["sync_data"], "value") #sometimes it sends just selected_label, not value...
             IJulia.set_cur_msg(msg)
             if view == :SelectMultiple
                 keys = msg.content["data"]["sync_data"]["value"]
-                if map(key->haskey(w.options, key), keys) |> all
+                if all(map(key->haskey(w.options, key), keys))
                     recv_msg(w, map(key->w.options[key], keys))
                 end
             else

src/IJulia/setup.jl

@@ -201,16 +201,24 @@ function update_view(w::Widget; prevw=w)
         remove_view(prevw)
         create_view(w)
     else
+        #w is same type as prevw
         if w !== prevw
             #new widget instance takes over the comm of the old instnace
             wire_comms(w, widget_comms[prevw])
             delete!(widget_comms, prevw)
         end
-        #update the view
-        send_comm(widget_comms[w], view_state(w))
+        #update all existing views of the widget
+        haskey(widget_comms, w) && send_comm(widget_comms[w], view_state(w))
     end
 end
 
+function remove_view(prevw::Widget)
+    #closing the comm removes ALL widget(s) associated with that comm
+    close_comm(widget_comms[prevw])
+    delete!(widget_comms, prevw)
+    nothing
+end
+
 function view_state(w::Widget; src::Widget=w)
     msg = viewdict(src)
     msg[:method] = "update"
@@ -229,30 +237,32 @@ function view_state(w::Widget; src::Widget=w)
 end
 
 function init_widget_dict(w::Widget)
-    Dict{Symbol, Any}(
-        :model_name => model_name(w),
-        :_model_name => model_name(w), # Jupyter 4.0 missing (https://github.com/ipython/ipywidgets/pull/84)
-        :_view_module => "jupyter-js-widgets",
-        :_model_module => "jupyter-js-widgets"
-    )
+    merge!(viewdict(w),
+        Dict{Symbol, Any}(
+            :model_name => model_name(w),
+            :_model_name => model_name(w), # Jupyter 4.0 missing (https://github.com/ipython/ipywidgets/pull/84)
+            :_view_module => "jupyter-js-widgets",
+            :_model_module => "jupyter-js-widgets"
+        ))
 end
 
-function remove_view(prevw::Widget)
-    #closing the comm removes ALL widget(s) associated with that comm
-    close_comm(widget_comms[prevw])
-    delete!(widget_comms, prevw)
-end
-
-function create_view(w::Widget)
+"""
+`create_view(w::Widget; displayw=true)`
+Creates the widget on the front-end and displays it if `displayw=true`
+Sets `widget_comms[w]` to the widget's comm
+returns the widget's Comm object
+"""
+function create_view(w::Widget; displayw=true)
     if haskey(widget_comms, w)
         comm = widget_comms[w]
     else
         #create the widget on the front-end by opening its comm
         comm = Comm("jupyter.widget", data=init_widget_dict(w))
         wire_comms(w, comm)
     end
-    send_comm(comm, view_state(w)) #set the state of newly created widget
-    send_comm(comm, @compat Dict(:method=>"display")) #tell front-end to display the widget
+    send_comm(comm, view_state(w)) #set/update the widget's state
+    displayw && send_comm(comm, @compat Dict(:method=>"display"))
+    comm
 end
 
 function wire_comms(w, comm)

src/Interact.jl

@@ -1,6 +1,6 @@
 module Interact
 
-using Reactive, Compat
+using Reactive, Compat, DataStructures
 
 import Base: mimewritable, writemime
 export signal, Widget, InputWidget

src/widgets.jl

@@ -7,6 +7,24 @@ export slider, togglebutton, button,
 
 const Empty = VERSION < v"0.4.0-dev" ? Nothing : Void
 
+"""Helps init widget's value and signal depending on which ones were set"""
+function init_wsigval(signal, value; default=value, typ=typeof(default))
+    if signal == nothing
+        if value == nothing
+            value = default
+        end
+        signal = Signal(typ, value)
+    else
+        #signal set
+        if value == nothing
+            value = signal.value
+        else
+            #signal set and value set
+            push!(signal, value)
+        end
+    end
+    signal, value
+end
 ### Input widgets
 
 ########################## Slider ############################
@@ -35,14 +53,30 @@ the starting `value` (defaults to the median of `range`), provide the
 `label` for the widget.
 """
 slider{T}(range::Range{T};
-          value=medianelement(range),
-          signal::Signal{T}=Signal(value),
+          value=nothing,
+          signal=nothing,
           label="",
           orientation="horizontal",
           readout=true,
           readout_format=T <: Integer ? "d" : ".3f",
-          continuous_update=true) =
-              Slider(signal, label, value, range, orientation, readout, readout_format, continuous_update)
+          continuous_update=true,
+          syncsig=true) = begin
+    signal, value = init_wsigval(signal, value; typ=T, default=medianelement(range))
+    s = Slider(signal, label, value, range, orientation,
+                readout, readout_format, continuous_update)
+    if syncsig
+        #keep the slider updated if the signal changes
+        keep_updated(new_value) = begin
+            if new_value != s.value
+                s.value = new_value
+                update_view(s)
+            end
+            nothing
+        end
+        preserve(map(keep_updated, signal; typ=Void))
+    end
+    s
+end
 
 ######################### Checkbox ###########################
 
@@ -61,11 +95,14 @@ Provide a checkbox with the specified starting (boolean)
 `value`. Optional provide a `label` for this widget and/or the
 (Reactive.jl) `signal` coupled to this widget.
 """
-checkbox(value::Bool; signal=Signal(value), label="") =
+checkbox(value::Bool; signal=nothing, label="") = begin
+    signal, value = init_wsigval(signal, value)
     Checkbox(signal, label, value)
-checkbox(; label="", value=false, signal=Signal(value)) =
+end
+checkbox(; label="", value=nothing, signal=nothing) = begin
+    signal, value = init_wsigval(signal, value; default=false)
     Checkbox(signal, label, value)
-
+end
 ###################### ToggleButton ########################
 
 type ToggleButton <: InputWidget{Bool}
@@ -76,8 +113,10 @@ end
 
 togglebutton(args...) = ToggleButton(args...)
 
-togglebutton(; label="", value=false, signal=Signal(value)) =
+togglebutton(; label="", value=nothing, signal=nothing) = begin
+    signal, value = init_wsigval(signal, value; default=false)
     ToggleButton(signal, label, value)
+end
 
 """
     togglebutton(label=""; value=false, signal)
@@ -114,7 +153,7 @@ button(label; kwargs...) =
 
 type Textbox{T} <: InputWidget{T}
     signal::Signal{T}
-    label::AbstractString
+    label::String
     @compat range::Union{Empty, Range}
     value::T
 end
@@ -126,16 +165,17 @@ function empty(t::Type)
 end
 
 function Textbox(; label="",
-                 value=utf8(""),
+                 value=nothing,
                  # Allow unicode characters even if initiated with ASCII
-                 typ=typeof(value),
+                 typ=String,
                  range=nothing,
-                 signal=Signal(typ, value))
+                 signal=nothing)
     if isa(value, AbstractString) && range != nothing
         throw(ArgumentError(
                "You cannot set a range on a string textbox"
              ))
     end
+    signal, value = init_wsigval(signal, value; typ=typ, default="")
     Textbox{typ}(signal, label, range, value)
 end
 
@@ -152,8 +192,8 @@ with `typ`. Optionally provide a `label`, specify the allowed range
 """
 textbox(val; kwargs...) =
     Textbox(value=val; kwargs...)
-textbox(val::AbstractString; kwargs...) =
-    Textbox(value=utf8(val); kwargs...)
+textbox(val::String; kwargs...) =
+    Textbox(value=val; kwargs...)
 
 parse_msg{T<:Number}(w::Textbox{T}, val::AbstractString) = parse_msg(w, parse(T, val))
 function parse_msg{T<:Number}(w::Textbox{T}, val::Number)
@@ -177,9 +217,11 @@ end
 textarea(args...) = Textarea(args...)
 
 textarea(; label="",
-         value="",
-         signal=Signal(value)) =
+         value=nothing,
+         signal=nothing) = begin
+    signal, value = init_wsigval(signal, value; default="")
     Textarea(signal, label, value)
+end
 
 """
     textarea(value=""; label="", signal)
@@ -194,21 +236,20 @@ textarea(val; kwargs...) =
 ##################### SelectionWidgets ######################
 
 immutable OptionDict
-    keys::Vector
-    dict::Dict
+    dict::OrderedDict
+    invdict::Dict
 end
 
 Base.getindex(x::OptionDict, y) = getindex(x.dict, y)
 Base.haskey(x::OptionDict, y) = haskey(x.dict, y)
-Base.keys(x::OptionDict) = x.keys
-Base.values(x::OptionDict) = [x.dict[k] for k in keys(x)]
+Base.keys(x::OptionDict) = keys(x.dict)
+Base.values(x::OptionDict) = values(x.dict)
 function Base.setindex!(x::OptionDict, v, k)
-    if !haskey(x.dict, k)
-        push!(x.keys, k)
-    end
     x.dict[k] = v
+    x.invdict[v] = k
     v
 end
+
 type Options{view, T} <: InputWidget{T}
     signal::Signal
     label::AbstractString
@@ -223,23 +264,43 @@ end
 
 Options(view::Symbol, options::OptionDict;
         label = "",
-        value_label=first(options.keys),
-        value=options[value_label],
+        value_label=first(keys(options)),
+        value=nothing,
         icons=[],
         tooltips=[],
         typ=valtype(options.dict),
-        signal=Signal(valtype(options.dict), value),
+        signal=nothing,
         readout=true,
-        orientation="horizontal") =
-    Options{view, typ}(signal, label, value, value_label,
-                       options, icons, tooltips, readout, orientation)
+        orientation="horizontal",
+        syncsig=true) = begin
+    signal, value = init_wsigval(signal, value; typ=typ, default=options[value_label])
+    ow = Options{view, typ}(signal, label, value, value_label,
+                    options, icons, tooltips, readout, orientation)
+    if syncsig
+        if view != :SelectMultiple
+            #set up map that keeps the value_label in sync with the value
+            #TODO handle SelectMultiple. Need something similar to handle_msg
+            keep_label_updated(new_value) = begin
+                if haskey(ow.options.invdict, new_value) &&
+                  ow.value_label != ow.options.invdict[new_value]
+                    ow.value_label = ow.options.invdict[new_value]
+                    update_view(ow)
+                end
+                nothing
+            end
+            preserve(map(keep_label_updated, signal; typ=Void))
+        end
+        push!(signal, value)
+    end
+    ow
+end
 
 addoption(opts, v::NTuple{2}) = opts[string(v[1])] = v[2]
 addoption(opts, v) = opts[string(v)] = v
 function Options(view::Symbol,
                     options::AbstractArray;
                     kwargs...)
-    opts = OptionDict(Any[], Dict())
+    opts = OptionDict(OrderedDict(), Dict())
     for v in options
         addoption(opts, v)
     end
@@ -249,7 +310,7 @@ end
 function Options(view::Symbol,
                     options::Associative;
                     kwargs...)
-    opts = OptionDict(Any[], Dict())
+    opts = OptionDict(OrderedDict(), Dict())
     for (k, v) in options
         opts[string(k)] = v
     end