builtins: switch takes single array as value

2 files changed, 42 insertions, 12 deletions

diff --git a/alv/builtins.moon b/alv/builtins.moon
index f612203..d76effc 100644
--- a/alv/builtins.moon
+++ b/alv/builtins.moon
@@ -330,24 +330,32 @@ switch_ = Constant.meta
   meta:
     name: 'switch'
     summary: "Switch between multiple inputs."
-    examples: { '(switch i v1 v2…)' }
+    examples: { '(switch i v1 v2…)', '(switch i arr)' }
     description: "
-- When fed a bang! trigger, steps forward to the next step on each trigger.
-- When fed a num~ or num! stream, reproduces the matching argument (indexed
+- When fed a num~ or num! stream, reproduces the matching value (indexed
   starting from 0).
-- When fed a bool~ or bool! stream, outputs the first or second argument for
-  `true` and `false` respectively. This version takes at most two argumetns."
+- When fed a bang! trigger, steps forward to the next step on each trigger.
+- When fed a bool~ or bool! stream, outputs the first or second value for
+  `true` and `false` respectively. This version takes at most two values.
+
+When only a single value is provided, it must be an array and is indexed as above."
 
   value: class extends Op
     pattern = (sig.num / sig.bool / evt.num / evt.bool / evt.bang) + any!!*0
     setup: (inputs) =>
       { i, values } = pattern\match inputs
 
-      val1 = values[1]
-      @setup_out val1.result.metatype, val1.result.type
-
       if i\type! == T.bang
-        @state or= 1
+        @state or= 0
+
+      val1 = values[1].result
+      if #values > 1
+        @length = nil
+        @setup_out val1.metatype, val1.type
+      else
+        assert val1.type.__class == Array, "single value must be array"
+        @length = val1.type.size
+        @setup_out val1.metatype, val1.type.type
 
       super
         i: Input.hot i
@@ -356,17 +364,24 @@ switch_ = Constant.meta
     tick: =>
       { :i, :values } = @inputs
 
+      length = @length or #values
+
       if i\type! == T.bang
         if i\dirty!
           @state += 1
-          @state = @state % (#values)
+          @state = @state % length
       else
         @state = switch i!
           when true then 0
           when false then 1
-          else (math.floor i!) % #values
+          else (math.floor i!) % length
 
-      @out\set if v = values[@state + 1] then v!
+      @out\set if @length
+        val = values[1]!
+        val and val[@state + 1]
+      else
+        val = values[@state + 1]
+        val and val!
 
     vis: =>
       with Op.vis @
diff --git a/spec/lib/builtins/cond_spec.moon b/spec/lib/builtins/cond_spec.moon
index 89f7c7e..04c56ef 100644
--- a/spec/lib/builtins/cond_spec.moon
+++ b/spec/lib/builtins/cond_spec.moon
@@ -90,3 +90,18 @@ describe "when", ->
       assert.is.true \is_const!
       assert.is.equal '<num[3]= [1 2 3]>', tostring .result
 
+
+describe "switch", ->
+  COPILOT = TestPilot!
+
+  it "switches by num", ->
+    for key, val in pairs {[0]: 11, [0.5]: 11, 22, 33, 11}
+      with COPILOT\eval_once "(switch #{key} 11 22 33)"
+        assert.is.true \is_const!
+        assert.is.equal val, .result!
+
+  it "switches arrays by num", ->
+    for key, val in pairs {[0]: 11, [0.5]: 11, 22, 33, 11}
+      with COPILOT\eval_once "(switch #{key} [11 22 33])"
+        assert.is.true \is_const!
+        assert.is.equal val, .result!