ptrigger.help.lhs

trigger :: [Bool] -> [a] -> [Maybe a]
ptrigger :: P Bool -> P a -> P (Maybe a)

  tr - boolean pattern
   x - value pattern

The 'tr' pattern determines the rate
at which values are read from the 'x'
pattern.  For each sucessive true 
value at 'tr' the output is a 'Just e'
of each succesive element at x.  False
values at 'tr' generate Nothing values. 

> import Sound.SC3.Lang.Pattern.List

> let { p = pseq [1, 2, 3] 1
>     ; t = pbool (pseq [0, 0, 1, 0, 0, 0, 1, 1] 1) } 
> in ptrigger t p

> let { p = [1, 2, 3]
>     ; t = bool [0, 0, 1, 0, 0, 0, 1, 1] }
> in trigger t p