122 lines
3.6 KiB
Haskell
122 lines
3.6 KiB
Haskell
-- | This module provides a monadic DSL in which the user can specify the
|
|
-- different rules used to run the compilers
|
|
--
|
|
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
|
|
module Hakyll.Core.Rules
|
|
( CompileRule (..)
|
|
, RuleSet (..)
|
|
, RulesM
|
|
, Rules
|
|
, runRules
|
|
, compile
|
|
, create
|
|
, route
|
|
, addCompilers
|
|
) where
|
|
|
|
import Control.Applicative (Applicative, (<$>))
|
|
import Control.Monad.Writer
|
|
import Control.Monad.Reader
|
|
import Control.Arrow (second, (>>>), arr, (>>^))
|
|
|
|
import Data.Typeable (Typeable)
|
|
import Data.Binary (Binary)
|
|
|
|
import Hakyll.Core.ResourceProvider
|
|
import Hakyll.Core.Identifier
|
|
import Hakyll.Core.Identifier.Pattern
|
|
import Hakyll.Core.Compiler.Internal
|
|
import Hakyll.Core.Route
|
|
import Hakyll.Core.CompiledItem
|
|
import Hakyll.Core.Writable
|
|
|
|
-- | Output of a compiler rule
|
|
--
|
|
-- * The compiler will produce a simple item. This is the most common case.
|
|
--
|
|
-- * The compiler will produce more compilers. These new compilers need to be
|
|
-- added to the runtime if possible, since other items might depend upon them.
|
|
--
|
|
data CompileRule = CompileRule CompiledItem
|
|
| MetaCompileRule [(Identifier, Compiler () CompileRule)]
|
|
|
|
-- | A collection of rules for the compilation process
|
|
--
|
|
data RuleSet = RuleSet
|
|
{ rulesRoute :: Route
|
|
, rulesCompilers :: [(Identifier, Compiler () CompileRule)]
|
|
}
|
|
|
|
instance Monoid RuleSet where
|
|
mempty = RuleSet mempty mempty
|
|
mappend (RuleSet r1 c1) (RuleSet r2 c2) =
|
|
RuleSet (mappend r1 r2) (mappend c1 c2)
|
|
|
|
-- | The monad used to compose rules
|
|
--
|
|
newtype RulesM a = RulesM
|
|
{ unRulesM :: ReaderT ResourceProvider (Writer RuleSet) a
|
|
} deriving (Monad, Functor, Applicative)
|
|
|
|
-- | Simplification of the RulesM type; usually, it will not return any
|
|
-- result.
|
|
--
|
|
type Rules = RulesM ()
|
|
|
|
-- | Run a Rules monad, resulting in a 'RuleSet'
|
|
--
|
|
runRules :: Rules -> ResourceProvider -> RuleSet
|
|
runRules rules provider = execWriter $ runReaderT (unRulesM rules) provider
|
|
|
|
-- | Add a route
|
|
--
|
|
tellRoute :: Route -> Rules
|
|
tellRoute route' = RulesM $ tell $ RuleSet route' mempty
|
|
|
|
-- | Add a number of compilers
|
|
--
|
|
tellCompilers :: (Binary a, Typeable a, Writable a)
|
|
=> [(Identifier, Compiler () a)]
|
|
-> Rules
|
|
tellCompilers compilers = RulesM $ tell $ RuleSet mempty $
|
|
map (second boxCompiler) compilers
|
|
where
|
|
boxCompiler = (>>> arr compiledItem >>> arr CompileRule)
|
|
|
|
-- | Add a compilation rule
|
|
--
|
|
-- This instructs all resources matching the given pattern to be compiled using
|
|
-- the given compiler
|
|
--
|
|
compile :: (Binary a, Typeable a, Writable a)
|
|
=> Pattern -> Compiler () a -> Rules
|
|
compile pattern compiler = RulesM $ do
|
|
identifiers <- matches pattern . resourceList <$> ask
|
|
unRulesM $ tellCompilers $ zip identifiers (repeat compiler)
|
|
|
|
-- | Add a compilation rule
|
|
--
|
|
-- This sets a compiler for the given identifier
|
|
--
|
|
create :: (Binary a, Typeable a, Writable a)
|
|
=> Identifier -> Compiler () a -> Rules
|
|
create identifier compiler = tellCompilers [(identifier, compiler)]
|
|
|
|
-- | Add a route
|
|
--
|
|
route :: Pattern -> Route -> Rules
|
|
route pattern route' = tellRoute $ ifMatch pattern route'
|
|
|
|
-- | Add a compiler that produces other compilers over time
|
|
--
|
|
addCompilers :: (Binary a, Typeable a, Writable a)
|
|
=> Identifier
|
|
-- ^ Identifier for this compiler
|
|
-> Compiler () [(Identifier, Compiler () a)]
|
|
-- ^ Compiler generating the other compilers
|
|
-> Rules
|
|
-- ^ Resulting rules
|
|
addCompilers identifier compiler = RulesM $ tell $ RuleSet mempty $
|
|
[(identifier, compiler >>^ makeRule)]
|
|
where
|
|
makeRule = MetaCompileRule . map (second (>>^ CompileRule . compiledItem))
|