{-# LANGUAGE DataKinds #-}
module Language where

import Data.Record
import Info
import Prologue
import Source
import qualified Syntax as S
import Term

-- | A programming language.
data Language =
      C
    | CoffeeScript
    | CPlusPlus
    | CSharp
    | CSS
    | Haskell
    | HTML
    | Java
    | JavaScript
    | Markdown
    | ObjectiveC
    | Perl
    | PHP
    | Python
    | R
    | Ruby
    | Swift
    deriving (Show)

-- | Returns a Language based on the file extension (including the ".").
languageForType :: Text -> Maybe Language
languageForType mediaType = case mediaType of
    ".h" -> Just C
    ".c" -> Just C
    ".js" -> Just JavaScript
    ".md" -> Just Markdown
    ".rb" -> Just Ruby
    _ -> Nothing

termConstructor
  :: Source Char -- ^ The source that the term occurs within.
  -> IO SourceSpan -- ^ The span that the term occupies. This is passed in 'IO' to guarantee some access constraints & encourage its use only when needed (improving performance).
  -> Text -- ^ The name of the production for this node.
  -> Range -- ^ The character range that the term occupies.
  -> [Term (S.Syntax Text) (Record '[Range, Category, SourceSpan])] -- ^ The child nodes of the term.
  -> IO (Term (S.Syntax Text) (Record '[Range, Category, SourceSpan])) -- ^ The resulting term, in IO.
termConstructor source sourceSpan name range children =
  withDefaultInfo $ case (name, children) of
    ("ERROR", _) -> S.Error children
    (_, []) -> S.Leaf (toText $ slice range source)
    _ -> S.Indexed children
  where
    withDefaultInfo syntax = do
      sourceSpan' <- sourceSpan
      pure $! cofree ((range .: Other name .: sourceSpan' .: RNil) :< syntax)