Improve APIs further

shared/_meta.lua

@@ -11,5 +11,5 @@ function klass()
 end
 
 function assert_range(i,mn,mx,name)
- assert(i >= mn and i < mx, name.." must be ["..mn..","..mx..")")
+ assert(i >= mn and i < mx, name.." must be ["..mn..","..mx..") and not "..i)
 end

shared/conductor.lua

@@ -0,0 +1,77 @@
+conductor=klass()
+function conductor:init(track,time)
+ self.track=track
+ self.time=time
+end
+
+function conductor:perform(
+ performers,
+ pitchblocks,
+ notation
+)
+ local n_performers=#performers
+ local n_pitchblocks=#pitchblocks.chunks
+
+ assert(#notation==n_performers,"need "..n_performers.." parts for "..n_performers.." performers")
+
+ for i=1,n_performers do
+  assert(#notation[i]==n_pitchblocks,"performers should have "..n_pitchblocks.." for "..n_pitchblocks.." pitchblocks")
+
+  local function resolve_pitch(t,ix)
+   local block = pitchblocks.chunks[t+1]
+   assert_range(ix,0,#block,"pitch ix")
+   return block[ix+1]
+  end
+
+  local running_note=nil
+
+  local function touch_running_note(
+   t,pitch,force_new,verbs
+  )
+   if force_new or (running_note and running_note.pitch != pitch) or (not running_note and pitch!=nil) then
+    if running_note then
+     performers[i].time=self.time+running_note.t
+     performers[i]:play(t-running_note.t,running_note.pitch,running_note.verbs)
+     running_note=nil
+    end
+    if pitch then
+     running_note={
+      t=t,
+      pitch=pitch,
+      verbs=verbs
+     }
+    end
+   end
+  end
+
+  for t=0,n_pitchblocks-1 do
+   local note_char=notation[i][t+1]
+   local pitch
+   local force_start_new 
+   local verbs=""
+
+   if note_char >= "a" and note_char <= "z" then
+    ix = ord(note_char) - ord("a") 
+    pitch=resolve_pitch(t,ix)
+   elseif note_char >= "A" and note_char <= "Z" then
+    ix = ord(note_char) - ord("A")
+    pitch=resolve_pitch(t,ix)
+    force_start_new = true
+   elseif note_char == "." then
+    pitch=nil
+   elseif note_char == "@" then
+    pitch,verbs=0,"kick"
+   elseif note_char == "!" then
+    pitch,verbs=0,"snare"
+   elseif note_char == "'" then
+    pitch,verbs=0,"hihat"
+   else
+    assert(false,"wtf? "..note_char)
+   end
+
+   touch_running_note(t,pitch,force_start_new,verbs)
+  end
+  touch_running_note(n_pitchblocks,nil)
+  performers[i].time=self.time
+ end
+end

shared/pitchblocks.lua

@@ -0,0 +1,14 @@
+pitchblocks=klass()
+function pitchblocks:init(width)
+ assert_range(width,0,8,"width")
+ self.width=width
+ self.chunks={}
+end
+
+function pitchblocks:add(n,notes)
+ assert(#notes==self.width)
+ for i=1,n do
+  add(self.chunks,notes)
+ end
+ return self
+end