Parse a ByteString into a FeatureVector.

Alias for fromByteString.

Render a FeatureVector to a ByteString, trimming leading zero bytes for compact encoding.

Set a bit by raw index.

>>> setBit 17 empty
FeatureVector {unFeatureVector = "\STX"}

Clear a bit by raw index.

>>> clearBit 17 (setBit 17 empty)
FeatureVector {unFeatureVector = ""}

Test if a bit is set.

>>> testBit 17 (setBit 17 empty)
True
>>> testBit 16 (setBit 17 empty)
False

Set a feature's bit at the given level.

Required sets the even bit, Optional sets the odd bit.

>>> import Data.Maybe (fromJust)
>>> let mpp = fromJust (featureByName "basic_mpp")
>>> setFeature mpp Optional empty  -- set optional bit (17)
FeatureVector {unFeatureVector = "\STX"}
>>> setFeature mpp Required empty  -- set required bit (16)
FeatureVector {unFeatureVector = "\SOH"}

Check if a feature is set in the vector.

Returns:

• Just Required if the required (even) bit is set
• Just Optional if the optional (odd) bit is set (and required is not)
• Nothing if neither bit is set

>>> import Data.Maybe (fromJust)
>>> let mpp = fromJust (featureByName "basic_mpp")
>>> hasFeature mpp (setFeature mpp Optional empty)
Just Optional
>>> hasFeature mpp (setFeature mpp Required empty)
Just Required
>>> hasFeature mpp empty
Nothing

Check if either bit of a feature is set in the vector.

>>> import Data.Maybe (fromJust)
>>> let mpp = fromJust (featureByName "basic_mpp")
>>> isFeatureSet mpp (setFeature mpp Optional empty)
True
>>> isFeatureSet mpp empty
False

List all known features that are set in the vector.

Returns pairs of (Feature, FeatureLevel) indicating whether each feature is set as required or optional.

>>> import Data.Maybe (fromJust)
>>> let mpp = fromJust (featureByName "basic_mpp")
>>> let ps = fromJust (featureByName "payment_secret")
>>> let fv = setFeature mpp Optional (setFeature ps Required empty)
>>> map (\(f, l) -> (featureName f, l)) (listFeatures fv)
[("payment_secret",Required),("basic_mpp",Optional)]