API for widgets to return possible bind values

frontend/common/SliderServerClient.js

@@ -14,7 +14,7 @@ export const slider_server_actions = ({ setStatePromise, launch_params, actions,
     notebookfile_hash.then((x) => console.log("Notebook file hash:", x))
 
     const bond_connections = notebookfile_hash
-        .then((hash) => fetch(trailingslash(launch_params.slider_server_url) + "bondconnections/" + encodeURIComponent(hash) + "/"))
+        .then((hash) => fetch(trailingslash(launch_params.slider_server_url) + "bondconnections/" + encodeURIComponent(hash) + ""))
         .then((r) => r.arrayBuffer())
         .then((b) => unpack(new Uint8Array(b)))
 
@@ -35,7 +35,12 @@ export const slider_server_actions = ({ setStatePromise, launch_params, actions,
             console.debug("Requesting bonds", bonds_to_set.current, to_send)
             bonds_to_set.current = new Set()
 
-            const mybonds_filtered = Object.fromEntries(Object.entries(mybonds).filter(([k, v]) => to_send.has(k)))
+            const mybonds_filtered = Object.fromEntries(
+                _.sortBy(
+                    Object.entries(mybonds).filter(([k, v]) => to_send.has(k)),
+                    ([k, v]) => k
+                )
+            )
 
             const packed = pack(mybonds_filtered)
 
@@ -75,11 +80,11 @@ export const slider_server_actions = ({ setStatePromise, launch_params, actions,
         set_bond: async (symbol, value, is_first_value) => {
             setStatePromise(
                 immer((state) => {
-                    state.notebook.bonds[symbol] = { value: value, is_first_value: is_first_value }
+                    state.notebook.bonds[symbol] = { value: value, is_first_value: true }
                 })
             )
             if (mybonds[symbol] == null || !_.isEqual(mybonds[symbol].value, value)) {
-                mybonds[symbol] = { value: _.cloneDeep(value), is_first_value: is_first_value }
+                mybonds[symbol] = { value: _.cloneDeep(value), is_first_value: true }
                 bonds_to_set.current.add(symbol)
                 await request_bond_response()
             }

src/evaluation/RunBonds.jl

@@ -45,3 +45,6 @@ function set_bond_values_reactive(; session::ServerSession, notebook::Notebook,
 
     run_reactive_async!(session, notebook, to_reeval; deletion_hook=custom_deletion_hook, user_requested_run=false, run_async=false, kwargs...)
 end
+
+"Returns the set of all possible values for the binded variable `n` as returned by the widget implementation using `AbstractPlutoDingetjes.possible_bond_values(element)`"
+possible_bond_values(session::ServerSession, notebook::Notebook, n::Symbol) = WorkspaceManager.possible_bond_values((session,notebook), n)

src/evaluation/WorkspaceManager.jl

@@ -154,6 +154,19 @@ function bump_workspace_module(session_notebook::SN)
     old_name, new_name
 end
 
+function possible_bond_values(session_notebook::SN, n::Symbol)
+    workspace = get_workspace(session_notebook)
+    pid = workspace.pid
+
+    possible_values = Distributed.remotecall_eval(Main, pid, quote
+        PlutoRunner.possible_bond_values($(QuoteNode(n)))
+    end)
+
+    @assert possible_values !== nothing "Tried to collect possible bind values when collection of possible bind values was not enabled"
+
+    possible_values
+end
+
 function create_emptyworkspacemodule(pid::Integer)::Symbol
     Distributed.remotecall_eval(Main, pid, :(PlutoRunner.increment_current_module()))
 end

src/notebook/Notebook.jl

@@ -9,7 +9,7 @@ mutable struct BondValue
     # This is only so the client can send this, the updater will always put this to `false`
     is_first_value::Bool
 end
-function Base.convert(::Type{BondValue}, dict::Dict)
+function Base.convert(::Type{BondValue}, dict::AbstractDict)
     BondValue(dict["value"], something(get(dict, "is_first_value", false), false))
 end
 

src/runner/PlutoRunner.jl

@@ -1297,12 +1297,14 @@ const integrations = Integration[
             @assert v"1.0.0" <= AbstractPlutoDingetjes.MY_VERSION < v"2.0.0"
             initial_value_getter_ref[] = AbstractPlutoDingetjes.Bonds.initial_value
             transform_value_ref[] = AbstractPlutoDingetjes.Bonds.transform_value
-
+            possible_bond_values_ref[] = AbstractPlutoDingetjes.Bonds.possible_values
+
             push!(supported_integration_features,
                 AbstractPlutoDingetjes,
                 AbstractPlutoDingetjes.Bonds,
                 AbstractPlutoDingetjes.Bonds.initial_value,
                 AbstractPlutoDingetjes.Bonds.transform_value,
+                AbstractPlutoDingetjes.Bonds.possible_values,
             )
         end,
     ),
@@ -1610,6 +1612,16 @@ function transform_bond_value(s::Symbol, value_from_js)
     end
 end
 
+function possible_bond_values(s::Symbol)
+    element = get(registered_bond_elements, s, nothing)
+    return try
+        possible_bond_values_ref[](element)
+    catch e
+        @error "Could not collect possible bond values for $s" exception=(e, catch_backtrace())
+        rethrow("Could not collect possible bond values for $s, err = $(string(e))")
+    end
+end
+
 """
 _“The name is Bond, James Bond.”_
 
@@ -1652,6 +1664,7 @@ end
 
 const initial_value_getter_ref = Ref{Function}(element -> missing)
 const transform_value_ref = Ref{Function}((element, x) -> x)
+const possible_bond_values_ref = Ref{Function}(_ -> throw("AbstractPlutoDingetjes is not loaded, could not collect possible bind values"))
 
 """
     `@bind symbol element`

test/Bonds.jl

@@ -90,6 +90,8 @@ import Pluto: update_run!, WorkspaceManager, ClientSession, ServerSession, Noteb
                     Base.show(io::IO, m::MIME"text/html", os::NewSlider) = write(io, "<input type=range value=1>")
 
                     Bonds.initial_value(os::NewSlider) = 1
+
+                    Bonds.possible_values(s::NewSlider) = [1,2,3]
                 end
                 """),
                 Cell("""
@@ -172,9 +174,8 @@ import Pluto: update_run!, WorkspaceManager, ClientSession, ServerSession, Noteb
         @test notebook.cells[7].output.body == "false"
         @test notebook.cells[8].output.body == "false"
 
-
-
-
+        @test Pluto.possible_bond_values(🍭, notebook, :x_new) == [1,2,3]
+
         @test noerror(notebook.cells[9])
         @test noerror(notebook.cells[10])
         @test noerror(notebook.cells[11])