Op: vis method instead of field

3 files changed, 27 insertions, 21 deletions

diff --git a/alv/base/op.moon b/alv/base/op.moon
index 625e1a8..f20518d 100644
--- a/alv/base/op.moon
+++ b/alv/base/op.moon
@@ -3,6 +3,7 @@
 --
 -- @classmod Op
 import deep_copy, deep_iter, deep_map from require 'alv.util'
+import T from require 'alv.type'
 
 class Op
 --- members
@@ -22,8 +23,7 @@ class Op
   fork: =>
     out = if @out then @out\fork!
     state = if @state then deep_copy @state
-    vis = if @vis then deep_copy @vis
-    @@ out, state, vis
+    @@ out, state
 
   --- internal state of this Op.
   --
@@ -32,16 +32,6 @@ class Op
   --
   -- @tfield table state
 
-  --- visualisation data of this Op.
-  --
-  -- This may be any simple Lua value, including Lua tables, as long as it has
-  -- no metatables, multiple references/loops, userdata etc.
-  --
-  -- This value is exposed to alv editors in order to render realtime
-  -- visualisations overlaid onto the program text.
-  --
-  -- @tfield table vis
-
   --- `Result` instance representing this Op's computed output value.
   --
   -- Must be set to a `Result` instance once `setup` finishes. Must not change
@@ -105,6 +95,23 @@ class Op
   --- called when the Op is destroyed (optional).
   destroy: =>
 
+  --- collect visualisation data (optional).
+  --
+  -- This may return any simple Lua value, including Lua tables, as long as it
+  -- has no metatables, multiple references/loops, userdata etc.
+  --
+  -- This value is exposed to alv editors in order to render realtime
+  -- visualisations overlaid onto the program text.
+  --
+  -- @treturn table vis
+  vis: =>
+    if @out and @out.metatype == '!'
+      { type: 'event' }
+    elseif @out and @out.type == T.bool
+      { type: 'bool' }
+    else
+      {}
+
 --- implementation utilities.
 --
 -- super-methods and utilities for use by implementations.
@@ -118,8 +125,7 @@ class Op
   -- @classmethod
   -- @tparam ?Result out `out`
   -- @tparam ?table state `state`
-  -- @tparam ?table vis `vis`
-  new: (@out, @state, @vis={}) =>
+  new: (@out, @state) =>
 
   do_setup = (old, cur) ->
     for k, cur_val in pairs cur
diff --git a/alv/builtins.moon b/alv/builtins.moon
index 12e78ba..d5d729c 100644
--- a/alv/builtins.moon
+++ b/alv/builtins.moon
@@ -309,8 +309,6 @@ switch_ = Constant.meta
 
       if i\type! == T.bang
         @state or= 1
-      else
-        @state = nil
 
       super
         i: Input.hot i
@@ -319,20 +317,22 @@ switch_ = Constant.meta
     tick: =>
       { :i, :values } = @inputs
 
-      ii = if i\type! == T.bang
+      if i\type! == T.bang
         if i\dirty!
           @state += 1
           while @state >= #values
             @state -= #values
         @state
       else
-        switch i!
+        @state = switch i!
           when true then 0
           when false then 1
           else (math.floor i!) % #values
+        @state
+
+      @out\set if v = values[@state + 1] then v!
 
-      @vis.step = ii
-      @out\set if v = values[ii + 1] then v!
+    vis: => step: @state
 
 trace_ = Constant.meta
   meta:
diff --git a/alv/copilot/udp.moon b/alv/copilot/udp.moon
index 5bf2ad4..7058b40 100644
--- a/alv/copilot/udp.moon
+++ b/alv/copilot/udp.moon
@@ -45,7 +45,7 @@ class UDPServer
         if builtin and builtin.__class.__name ~= 'DummyReg'
           res.head_meta = builtin.head.meta
           res.result = encode_res builtin.node.result
-          res.vis = if builtin.op then builtin.op.vis
+          res.vis = if builtin.op then builtin.op\vis!
           res.kind = switch builtin.__class
             when op_invoke then 'op'
             when fn_invoke then 'fn'