timeline chance

chance.lua

--- some possible implementations of a probable function
-- really comes down to whether it's a timeline native behaviour
-- or if we just want a general fn to a wrap an application with chance

-- original version without chance
notesss = { 1, kick
          , 1, {ii.wsyn.play_note, s{0,-12}, 2}
          }

-- tl.chance is a function that takes a probability, and an action
-- note: the action can be an 'action table' in the timeline sense, to be applied at runtime
notesss = { 1, tl.chance(0.5, kick)
          , 1, tl.chance(0.6, {ii.wsyn.play_note, s{0,-12}, 2})
          }

-- some as tl.chance, but instead it's a *global* function for probablistically calling it's 2nd arg
-- nb: requires handling of table-actions, which is perhaps timeline specific?
notesss = { 1, chance(0.5, kick)
          , 1, chance(0.6, {ii.wsyn.play_note, s{0,-12}, 2})
          }

-- same again, but here we don't allow chance to have an action table
-- instead it just returns a fn that might execute it's inner-section
-- nb: any sequins will always advance, even if chance doesn't succeed
notesss = { 1, chance(0.5, kick)
          , 1, {chance(0.6, ii.wsyn.play_note), s{0,-12}, 2})
          }

-- here we support it directly in timeline as a probability string
-- we already have a similar technique for "reset"
-- this gets weird because the action-table starts to get quite long
-- ? should the following action be sub-tabled, or is this clear enough?
-- strings are annoying bc math is hard, but numbers (0.5) are not clear as to what their purpose is
notesss = { 1, {'50%', kick}
          , 1, {'60%', ii.wsyn.play_note, s{0,-12}, 2}
          }

-- this is a simple version of timeline.apply
-- this does *not* support realizing sequins values within the action-table
function apply(fn, ...)
    if type(fn) == 'table' then
        return apply(table.unpack(fn)) -- unpack & recur
    else return fn(...) end
end

function chance(prob, ...)
    return function()
        if math.random() <= prob then
            return apply(...)
        end
    end
end