module TagAttrs(module TagAttrs,(<>)) where
import Data.Semigroup

newtype TagAttrs = TA [TagAttr] deriving (Eq,Show)
type TagAttr = (AttrName,AttrValue)
type AttrName = String
type AttrValue = String

lookupAttr n (TA as) = lookup n as

implicit = TA [("implicit","")]
noAttrs = TA []
attrs = TA

hasAttr n (TA as) = not $ null [()|(m,_)<-as,m==n]
mapAttrs f (TA as) = TA (map f as)

instance Semigroup TagAttrs where TA as1<>TA as2 = TA (as1++as2)