module Util.Template (Template,makeTemplate,applyTemplate) where
import Text.Pandoc.Definition
import Text.Pandoc.Generic
import Text.Pandoc.Shared (normalizeInlines)
import Data.Maybe
import Util.Meta
type VarFunc = String -> Maybe MetaValue
newtype Template = Template (VarFunc -> [Inline])
makeTemplate :: Meta -> [Inline] -> Template
makeTemplate dtv = Template . flip scan . scan (`lookupMeta` dtv)
where
scan = bottomUp . go
go vf (x@(Math DisplayMath var):xs) = replaceVar (vf var) [x] ++ xs
go _ x = x
replaceVar val def' = fromMaybe def' $ val >>= toInlines
applyTemplate :: [Inline] -> [Inline] -> Template -> [Inline]
applyTemplate i t (Template g) =
normalizeInlines $ g internalVars
where
internalVars "i" = Just $ MetaInlines i
internalVars "t" = Just $ MetaInlines t
internalVars _ = Nothing