add trigseq to lib/rhythm

1 files changed, 43 insertions, 2 deletions

diff --git a/alv-lib/rhythm.moon b/alv-lib/rhythm.moon
index 35d57ae..8170cf9 100644
--- a/alv-lib/rhythm.moon
+++ b/alv-lib/rhythm.moon
@@ -39,7 +39,7 @@ euclid = Constant.meta
   meta:
     name: 'euclid'
     summary: "Generate euclidean rhythms."
-    examples: { '(euclid i n k)', '(euclid trigger! n k)' }
+    examples: { '(euclid trig! n k)', '(euclid i n k)' }
     description: "Generates bangs according to the Euclidean algorithm.
 
 When fed a bang! trigger, steps forward to the next step on each trigger.
@@ -67,7 +67,7 @@ When fed a num~ or num! stream, outputs a bang if the corresponding step is on."
 
       if @inputs.trig\type! == T.bang
         @state += 1
-        if @state > n
+        if @state >= n
           @state -= n
 
       i = 1 + (@state or trig % n)
@@ -75,6 +75,47 @@ When fed a num~ or num! stream, outputs a bang if the corresponding step is on."
       if '1' == pat\sub i, i
         @out\set true
 
+trigseq = Constant.meta
+  meta:
+    name: 'trigseq'
+    summary: "Generate rhythms based on a trigger-sequence"
+    examples: { '(trigseq trig! [s1 s2…])', '(trigseq i [s1 s2…])' }
+    description: "Generates bangs according to the sequence `s1`, `s2`, …
+
+Each step should be a bool~ that determines whether a bang should be emitted on
+that step or not.
+
+When fed a bang! trigger, steps forward to the next step on each trigger.
+When fed a num~ or num! stream, outputs a bang if the corresponding step is on."
+
+  value: class extends Op
+    pattern = (evt.bang / val.num / evt.num) + val.bool*0
+    setup: (inputs) =>
+      { trig, steps } = pattern\match inputs
+
+      @out or= T.bang\mk_evt!
+
+      super
+        trig: Input.hot trig
+        steps: [Input.cold s for s in *steps]
+
+      if @inputs.trig\type! == T.bang
+        @state or= 1
+      else
+        @state = nil
+
+    tick: =>
+      n = #@inputs.steps
+      if @inputs.trig\type! == T.bang
+        @state += 1
+        if @state >= n
+          @state -= n
+
+      i = 1 + (@state or trig % n)
+      if @inputs.steps[i]!
+        @out\set true
+
 {
   :euclid
+  :trigseq
 }