Pattern to list?

Questions and Answers
1

Simple-sounding question here. I'm trying to use patterns to make "spicy" lists.

The following example is maybe a bit weird, but you don't have to worry about the details. Let's say I create a pattern:

toScale [0, 2, 5] (fromIntegral <$> round <$> segment 12 (range 1 14 $ abs (sine * (fast 2 $ sine)))) .

This pattern maps time to values:

(0>1/12)|26
 (1/12>⅙)|48
    (⅙>¼)|41
    (¼>⅓)|14
 (⅓>5/12)|2
 (5/12>½)|12
 (½>7/12)|17
 (7/12>⅔)|12
    (⅔>¾)|2
    (¾>⅚)|2
(⅚>11/12)|2
(11/12>1)|5

How does one create a list out of the values?

I'm expecting a list with 12 elements, [26, 48, 41, 14, 2, 12, 17, 12, 2, 2, 2, 5].

I've tried putting square braces around the pattern, but that creates a list of patterns--not what i'm after. I tried appending :: [Double] and some other things and searches but no luck.

:orangutan:

1 Like
2

Hey !
the following seems to work:

patternToList :: Pattern a -> [a] 
patternToList pat = (map value (queryArc pat (Arc 0 1)))

I'd be interested what you're gonna do with the lists :smiley:

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3

Yeah that works great! Thank you so much! :smiley:

I'm trying to use the lists in nTake and see what you can get with the new state memory in Tidal.

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4

I would warn that there's a gotcha here - queryArc doesn't sort its output, so there's no guarantee that list you get will be time-ordered. If you want to make sure you have a "chronological" output you'd want to do something like

import Data.List
patternToList pat = map value $ sortOn whole $ queryArc pat (Arc 0 1)
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5

Thank you kindly, @bgold . I do indeed want this chronological input. :smiley: