softclock - mockup of soft-timer system in lua

softclock.lua

-- module for creating collections of soft-timers based on a single fast "superclock"

-- this is a simple singleton implementation for test/mockup
-- TODO: allow multiple instances
-- TODO: allow changing the superclock period

local softclock = {}

-- this field represents the period of the superclock, in seconds
softclock.super_period = 1/128

softclock.clocks = {}

-- call this from the superclock
softclock.tick = function() 
    for id,clock in pairs(softclock.clocks) do
        clock.phase_ticks = clock.phase_ticks + 1
        
        -- asumption: subclock period is > 1 tick
        if clock.phase_ticks > clock.period_ticks then
            -- save the remainder
            -- (this might need to be a while-loop to catch edge cases?)
            clock.phase_ticks = clock.phase_ticks - clock.period_ticks
            -- and fire the event
            -- (maybe it is useful for the event to get the fractional phase, IDK)
            clock.event(clock.phase_ticks)
        end
    end
end 

softclock.add = function(id, period, event) 
    local c = {} -- new subclock table
    c.phase_ticks = 0
    -- convert argument from seconds to superclock ticks
    c.period_ticks = period / softclock.super_period
    print('adding clock; id ='..id..'; period_ticks='..c.period_ticks)
    c.event = event
    softclock.clocks[id] = c
end 

softclock.remove = function(id) 
    -- TODO
end 

softclock.clear = function() 
    -- TODO
end 

return softclock

test_softclock.lua

--- test of softclock module

local softclock = include('lib/softclock')

local function super_tick()
  softclock.tick()
end 

function init()
    super_period = 1/8
    super_metro = metro.init({time =super_period, event=super_tick})
    softclock.super_period = super_period
    
    softclock.add('a', 1/4, function(phase) print("a:"..phase) end)
    softclock.add('b', 3/4, function(phase) print("b:"..phase) end)
    softclock.add('c', 11/17, function(phase) print("c:"..phase) end)

    super_metro:start()
end