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|
--------------------------------------------------------------------------------
-- | Internally used compiler module
{-# LANGUAGE GADTs #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
module Hakyll.Core.Compiler.Internal
( -- * Types
CompilerRead (..)
, CompilerWrite (..)
, CompilerResult (..)
, Compiler (..)
, runCompiler
-- * Core operations
, compilerTell
, compilerAsk
, compilerThrow
, compilerCatch
, compilerResult
, compilerUnsafeIO
-- * Utilities
, compilerTellDependencies
, compilerTellCacheHits
) where
--------------------------------------------------------------------------------
import Control.Applicative (Alternative (..),
Applicative (..), (<$>))
import Control.Exception (SomeException, handle)
import Data.Monoid (Monoid (..))
import Data.Set (Set)
import qualified Data.Set as S
--------------------------------------------------------------------------------
import Hakyll.Core.Configuration
import Hakyll.Core.Dependencies
import Hakyll.Core.Identifier
import Hakyll.Core.Identifier.Pattern
import Hakyll.Core.Logger
import Hakyll.Core.Metadata
import Hakyll.Core.Provider
import Hakyll.Core.Routes
import Hakyll.Core.Store
--------------------------------------------------------------------------------
-- | Environment in which a compiler runs
data CompilerRead = CompilerRead
{ -- | Main configuration
compilerConfig :: Configuration
, -- | Underlying identifier
compilerUnderlying :: Identifier
, -- | Resource provider
compilerProvider :: Provider
, -- | List of all known identifiers
compilerUniverse :: Set Identifier
, -- | Site routes
compilerRoutes :: Routes
, -- | Compiler store
compilerStore :: Store
, -- | Logger
compilerLogger :: Logger
}
--------------------------------------------------------------------------------
data CompilerWrite = CompilerWrite
{ compilerDependencies :: [Dependency]
, compilerCacheHits :: Int
} deriving (Show)
--------------------------------------------------------------------------------
instance Monoid CompilerWrite where
mempty = CompilerWrite [] 0
mappend (CompilerWrite d1 h1) (CompilerWrite d2 h2) =
CompilerWrite (d1 ++ d2) (h1 + h2)
--------------------------------------------------------------------------------
data CompilerResult a where
CompilerDone :: a -> CompilerWrite -> CompilerResult a
CompilerError :: String -> CompilerResult a
CompilerRequire :: Identifier -> Compiler a -> CompilerResult a
--------------------------------------------------------------------------------
-- | A monad which lets you compile items and takes care of dependency tracking
-- for you.
newtype Compiler a = Compiler
{ unCompiler :: CompilerRead -> IO (CompilerResult a)
}
--------------------------------------------------------------------------------
instance Functor Compiler where
fmap f (Compiler c) = Compiler $ \r -> do
res <- c r
return $ case res of
CompilerDone x w -> CompilerDone (f x) w
CompilerError e -> CompilerError e
CompilerRequire i c' -> CompilerRequire i (fmap f c')
{-# INLINE fmap #-}
--------------------------------------------------------------------------------
instance Monad Compiler where
return x = Compiler $ \_ -> return $ CompilerDone x mempty
{-# INLINE return #-}
Compiler c >>= f = Compiler $ \r -> do
res <- c r
case res of
CompilerDone x w -> do
res' <- unCompiler (f x) r
return $ case res' of
CompilerDone y w' -> CompilerDone y (w `mappend` w')
CompilerError e -> CompilerError e
CompilerRequire i c' -> CompilerRequire i $ do
compilerTell w -- Save dependencies!
c'
CompilerError e -> return $ CompilerError e
CompilerRequire i c' -> return $ CompilerRequire i $ c' >>= f
{-# INLINE (>>=) #-}
fail = compilerThrow
{-# INLINE fail #-}
--------------------------------------------------------------------------------
instance Applicative Compiler where
pure x = return x
{-# INLINE pure #-}
f <*> x = f >>= \f' -> fmap f' x
{-# INLINE (<*>) #-}
--------------------------------------------------------------------------------
instance MonadMetadata Compiler where
getMetadata = compilerGetMetadata
getMatches = compilerGetMatches
--------------------------------------------------------------------------------
runCompiler :: Compiler a -> CompilerRead -> IO (CompilerResult a)
runCompiler compiler read' = handle handler $ unCompiler compiler read'
where
handler :: SomeException -> IO (CompilerResult a)
handler e = return $ CompilerError $ show e
--------------------------------------------------------------------------------
instance Alternative Compiler where
empty = compilerThrow "Hakyll.Core.Compiler.Internal: empty alternative"
x <|> y = compilerCatch x (\_ -> y)
{-# INLINE (<|>) #-}
--------------------------------------------------------------------------------
compilerAsk :: Compiler CompilerRead
compilerAsk = Compiler $ \r -> return $ CompilerDone r mempty
{-# INLINE compilerAsk #-}
--------------------------------------------------------------------------------
compilerTell :: CompilerWrite -> Compiler ()
compilerTell deps = Compiler $ \_ -> return $ CompilerDone () deps
{-# INLINE compilerTell #-}
--------------------------------------------------------------------------------
compilerThrow :: String -> Compiler a
compilerThrow e = Compiler $ \_ -> return $ CompilerError e
{-# INLINE compilerThrow #-}
--------------------------------------------------------------------------------
compilerCatch :: Compiler a -> (String -> Compiler a) -> Compiler a
compilerCatch (Compiler x) f = Compiler $ \r -> do
res <- x r
case res of
CompilerDone res' w -> return (CompilerDone res' w)
CompilerError e -> unCompiler (f e) r
CompilerRequire i c -> return (CompilerRequire i (compilerCatch c f))
{-# INLINE compilerCatch #-}
--------------------------------------------------------------------------------
-- | Put the result back in a compiler
compilerResult :: CompilerResult a -> Compiler a
compilerResult x = Compiler $ \_ -> return x
{-# INLINE compilerResult #-}
--------------------------------------------------------------------------------
compilerUnsafeIO :: IO a -> Compiler a
compilerUnsafeIO io = Compiler $ \_ -> do
x <- io
return $ CompilerDone x mempty
{-# INLINE compilerUnsafeIO #-}
--------------------------------------------------------------------------------
compilerTellDependencies :: [Dependency] -> Compiler ()
compilerTellDependencies ds = compilerTell mempty {compilerDependencies = ds}
{-# INLINE compilerTellDependencies #-}
--------------------------------------------------------------------------------
compilerTellCacheHits :: Int -> Compiler ()
compilerTellCacheHits ch = compilerTell mempty {compilerCacheHits = ch}
{-# INLINE compilerTellCacheHits #-}
--------------------------------------------------------------------------------
compilerGetMetadata :: Identifier -> Compiler Metadata
compilerGetMetadata identifier = do
provider <- compilerProvider <$> compilerAsk
compilerTellDependencies [IdentifierDependency identifier]
compilerUnsafeIO $ resourceMetadata provider identifier
--------------------------------------------------------------------------------
compilerGetMatches :: Pattern -> Compiler [Identifier]
compilerGetMatches pattern = do
universe <- compilerUniverse <$> compilerAsk
let matching = filterMatches pattern $ S.toList universe
compilerTellDependencies [PatternDependency pattern matching]
return matching
|
