diff options
Diffstat (limited to 'applause.lua')
| -rw-r--r-- | applause.lua | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/applause.lua b/applause.lua index 404efef..171bd2d 100644 --- a/applause.lua +++ b/applause.lua @@ -1682,6 +1682,64 @@ end function Stream:ftom() return self:map(ftom) end +InstrumentStream = DeriveClass(MuxableStream) + +InstrumentStream.sig_last_stream = 1 + +function InstrumentStream:muxableCtor(note_stream, on_stream, off_stream) + note_stream = tostream(note_stream):cache() + + if type(on_stream) == "function" then + on_stream = on_stream(self.note_stream) + else + on_stream = tostream(on_stream) + end + if type(off_stream) == "function" then + off_stream = off_stream(self.note_stream) + else + -- The "off" stream is optional + off_stream = off_stream and tostream(off_stream) + end + + self.streams = {note_stream, on_stream, off_stream} +end + +function InstrumentStream:tick() + local note_tick = self.streams[1]:tick() + local on_stream = self.streams[2] + local off_stream = self.streams[3] + local on_tick + local function off_tick() return 0 end + + return function() + local note = note_tick() + if not note then return end + + if on_tick == nil then -- no note + if note == 0 then return off_tick() or 0 end + + -- FIXME: This is not strictly real-time safe + on_tick = on_stream:tick() + return on_tick() or 0 + else -- note on + if note ~= 0 then return on_tick() or 0 end + + -- FIXME: This is not strictly real-time safe + on_tick = nil + off_tick = off_stream and off_stream:tick() + return off_tick() or 0 + end + end +end + +function InstrumentStream:len() + return self.streams[1]:len() +end + +function Stream:instrument(on_stream, off_stream) + return InstrumentStream:new(self, on_stream, off_stream) +end + -- primitives function tostream(v) |