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|
--------------------------------------------------------------------------------
-- | This module provides a declarative DSL in which the user can specify the
-- different rules used to run the compilers.
--
-- The convention is to just list all items in the 'Rules' monad, routes and
-- compilation rules.
--
-- A typical usage example would be:
--
-- > main = hakyll $ do
-- > match "posts/*" $ do
-- > route (setExtension "html")
-- > compile someCompiler
-- > match "css/*" $ do
-- > route idRoute
-- > compile compressCssCompiler
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}
module Hakyll.Core.Rules
( Rules
, match
, matchMetadata
, create
, version
, compile
, route
-- * Advanced usage
, preprocess
, Dependency (..)
, rulesExtraDependencies
) where
--------------------------------------------------------------------------------
import Control.Monad.Reader (ask, local)
import Control.Monad.State (get, modify, put)
import Control.Monad.Trans (liftIO)
import Control.Monad.Writer (censor, tell)
import Data.Maybe (fromMaybe)
import qualified Data.Set as S
--------------------------------------------------------------------------------
import Data.Binary (Binary)
import Data.Typeable (Typeable)
--------------------------------------------------------------------------------
import Hakyll.Core.Compiler.Internal
import Hakyll.Core.Dependencies
import Hakyll.Core.Identifier
import Hakyll.Core.Identifier.Pattern
import Hakyll.Core.Item
import Hakyll.Core.Item.SomeItem
import Hakyll.Core.Metadata
import Hakyll.Core.Routes
import Hakyll.Core.Rules.Internal
import Hakyll.Core.Writable
--------------------------------------------------------------------------------
-- | Add a route
tellRoute :: Routes -> Rules ()
tellRoute route' = Rules $ tell $ RuleSet route' mempty mempty mempty
--------------------------------------------------------------------------------
-- | Add a number of compilers
tellCompilers :: [(Identifier, Compiler SomeItem)] -> Rules ()
tellCompilers compilers = Rules $ tell $ RuleSet mempty compilers mempty mempty
--------------------------------------------------------------------------------
-- | Add resources
tellResources :: [Identifier] -> Rules ()
tellResources resources' = Rules $ tell $
RuleSet mempty mempty (S.fromList resources') mempty
--------------------------------------------------------------------------------
-- | Add a pattern
tellPattern :: Pattern -> Rules ()
tellPattern pattern = Rules $ tell $ RuleSet mempty mempty mempty pattern
--------------------------------------------------------------------------------
flush :: Rules ()
flush = Rules $ do
mcompiler <- rulesCompiler <$> get
case mcompiler of
Nothing -> return ()
Just compiler -> do
matches' <- rulesMatches <$> ask
version' <- rulesVersion <$> ask
route' <- fromMaybe mempty . rulesRoute <$> get
-- The version is possibly not set correctly at this point (yet)
let ids = map (setVersion version') matches'
{-
ids <- case fromLiteral pattern of
Just id' -> return [setVersion version' id']
Nothing -> do
ids <- unRules $ getMatches pattern
unRules $ tellResources ids
return $ map (setVersion version') ids
-}
-- Create a fast pattern for routing that matches exactly the
-- compilers created in the block given to match
let fastPattern = fromList ids
-- Write out the compilers and routes
unRules $ tellRoute $ matchRoute fastPattern route'
unRules $ tellCompilers $ [(id', compiler) | id' <- ids]
put $ emptyRulesState
--------------------------------------------------------------------------------
matchInternal :: Pattern -> Rules [Identifier] -> Rules () -> Rules ()
matchInternal pattern getIDs rules = do
tellPattern pattern
flush
ids <- getIDs
tellResources ids
Rules $ local (setMatches ids) $ unRules $ rules >> flush
where
setMatches ids env = env {rulesMatches = ids}
--------------------------------------------------------------------------------
match :: Pattern -> Rules () -> Rules ()
match pattern = matchInternal pattern $ getMatches pattern
--------------------------------------------------------------------------------
matchMetadata :: Pattern -> (Metadata -> Bool) -> Rules () -> Rules ()
matchMetadata pattern metadataPred = matchInternal pattern $
map fst . filter (metadataPred . snd) <$> getAllMetadata pattern
--------------------------------------------------------------------------------
create :: [Identifier] -> Rules () -> Rules ()
create ids rules = do
flush
-- TODO Maybe check if the resources exist and call tellResources on that
Rules $ local setMatches $ unRules $ rules >> flush
where
setMatches env = env {rulesMatches = ids}
--------------------------------------------------------------------------------
version :: String -> Rules () -> Rules ()
version v rules = do
flush
Rules $ local setVersion' $ unRules $ rules >> flush
where
setVersion' env = env {rulesVersion = Just v}
--------------------------------------------------------------------------------
-- | Add a compilation rule to the rules.
--
-- This instructs all resources to be compiled using the given compiler.
compile :: (Binary a, Typeable a, Writable a) => Compiler (Item a) -> Rules ()
compile compiler = Rules $ modify $ \s ->
s {rulesCompiler = Just (fmap SomeItem compiler)}
--------------------------------------------------------------------------------
-- | Add a route.
--
-- This adds a route for all items matching the current pattern.
route :: Routes -> Rules ()
route route' = Rules $ modify $ \s -> s {rulesRoute = Just route'}
--------------------------------------------------------------------------------
-- | Execute an 'IO' action immediately while the rules are being evaluated.
-- This should be avoided if possible, but occasionally comes in useful.
preprocess :: IO a -> Rules a
preprocess = Rules . liftIO
--------------------------------------------------------------------------------
-- | Advanced usage: add extra dependencies to compilers. Basically this is
-- needed when you're doing unsafe tricky stuff in the rules monad, but you
-- still want correct builds.
--
-- A useful utility for this purpose is 'makePatternDependency'.
rulesExtraDependencies :: [Dependency] -> Rules a -> Rules a
rulesExtraDependencies deps rules =
-- Note that we add the dependencies seemingly twice here. However, this is
-- done so that 'rulesExtraDependencies' works both if we have something
-- like:
--
-- > match "*.css" $ rulesExtraDependencies [foo] $ ...
--
-- and something like:
--
-- > rulesExtraDependencies [foo] $ match "*.css" $ ...
--
-- (1) takes care of the latter and (2) of the former.
Rules $ censor fixRuleSet $ do
x <- unRules rules
fixCompiler
return x
where
-- (1) Adds the dependencies to the compilers we are yet to create
fixCompiler = modify $ \s -> case rulesCompiler s of
Nothing -> s
Just c -> s
{ rulesCompiler = Just $ compilerTellDependencies deps >> c
}
-- (2) Adds the dependencies to the compilers that are already in the ruleset
fixRuleSet ruleSet = ruleSet
{ rulesCompilers =
[ (i, compilerTellDependencies deps >> c)
| (i, c) <- rulesCompilers ruleSet
]
}
|
