heist-0.14.1: An Haskell template system supporting both HTML5 and XML.

Safe HaskellNone
LanguageHaskell98

Heist

Contents

Description

This module defines the core data types used by Heist. In practice you will also want to import one or both of Heist.Compiled or Heist.Interpreted to get functions needed for writing splices.

The Heist template system allows you to build custom HTML and XML based markup languages. With Heist you can define your own domain-specific tags implemented with Haskell and use them in your templates.

Synopsis

Primary Heist initialization functions

loadTemplates :: FilePath -> EitherT [String] IO TemplateRepo Source

Loads templates from disk. This function returns just a template map so you can load multiple directories and combine the maps before initializing your HeistState.

reloadTemplates :: TemplateRepo -> EitherT [String] IO TemplateRepo Source

Reloads all the templates an an existing TemplateRepo.

addTemplatePathPrefix :: ByteString -> TemplateRepo -> TemplateRepo Source

Adds a path prefix to a templates in a map returned by loadTemplates. If you want to add multiple levels of directories, separate them with slashes as in "foo/bar". Using an empty string as a path prefix will leave the map unchanged.

initHeist :: Monad n => HeistConfig n -> EitherT [String] IO (HeistState n) Source

This is the main Heist initialization function. You pass in a map of all templates and all of your splices and it constructs and returns a HeistState.

We don't provide functions to add either type of loadtime splices to your HeistState after initHeist because it doesn't make any sense unless you re-initialize all templates with the new splices. If you add any old-style runtime heist splices after calling this function, they will still work fine if you use Heist.Interpreted.renderTemplate. If you add any templates later, then those templates will be available for interpreted rendering, but not for compiled rendering.

In the past you could add templates to your HeistState after initialization using its Monoid instance. Due to implementation details, this is no longer possible. All of your templates must be known when you call this function.

initHeistWithCacheTag :: MonadIO n => HeistConfig n -> EitherT [String] IO (HeistState n, CacheTagState) Source

Wrapper around initHeist that also sets up a cache tag. It sets up both compiled and interpreted versions of the cache tag splices. If you need to configure the cache tag differently than how this function does it, you will still probably want to pattern your approach after this function's implementation.

defaultInterpretedSplices :: MonadIO m => Splices (Splice m) Source

The built-in set of static splices. All the splices that used to be enabled by default are included here. To get the normal Heist behavior you should include these in the scLoadTimeSplices list in your SpliceConfig. If you are using interpreted splice mode, then you might also want to bind the deprecatedContentCheck splice to the content tag as a load time splice.

defaultLoadTimeSplices :: MonadIO m => Splices (Splice m) Source

The built-in set of splices that you should use in compiled splice mode. This list includes everything from defaultInterpretedSplices plus a splice for the content tag that errors out when it sees any instance of the old content tag, which has now been moved to two separate tags called apply-content and bind-content.

emptyHeistConfig :: HeistConfig m Source

An empty HeistConfig that uses the "h" namespace with error checking turned on.

Core Heist data types

data SpliceConfig m Source

The splices and templates Heist will use. To bind a splice simply include it in the appropriate place here.

Instances

type TemplateLocation = EitherT [String] IO TemplateRepo Source

An IO action for getting a template repo from this location. By not just using a directory path here, we support templates loaded from a database, retrieved from the network, or anything else you can think of.

type Template = [Node] Source

A Template is a forest of XML nodes. Here we deviate from the "single root node" constraint of well-formed XML because we want to allow templates to contain document fragments that may not have a single root.

type TPath = [ByteString] Source

Reversed list of directories. This holds the path to the template currently being processed.

type MIMEType = ByteString Source

MIME Type. The type alias is here to make the API clearer.

data DocumentFile Source

Holds data about templates read from disk.

Constructors

DocumentFile 

type AttrSplice m = Text -> RuntimeSplice m [(Text, Text)] Source

Type alias for attribute splices. The function parameter is the value of the bound attribute splice. The return value is a list of attribute key/value pairs that get substituted in the place of the bound attribute.

data RuntimeSplice m a Source

Monad used for runtime splice execution.

data Chunk m Source

Opaque type representing pieces of output from compiled splices.

Instances

Show (Chunk m) 
Typeable ((* -> *) -> *) Chunk 

data HeistState m Source

Holds all the state information needed for template processing. You will build a HeistState using initHeist and any of Heist's HeistState -> HeistState "filter" functions. Then you use the resulting HeistState in calls to renderTemplate.

m is the runtime monad

Instances

Typeable ((* -> *) -> *) HeistState 

data HeistT n m a Source

HeistT is the monad transformer used for splice processing. HeistT intentionally does not expose any of its functionality via MonadState or MonadReader functions. We define passthrough instances for the most common types of monads. These instances allow the user to use HeistT in a monad stack without needing calls to lift.

n is the runtime monad (the parameter to HeistState).

m is the monad being run now. In this case, "now" is a variable concept. The type HeistT n n means that "now" is runtime. The type HeistT n IO means that "now" is IO, and more importantly it is NOT runtime. In Heist, the rule of thumb is that IO means load time and n means runtime.

Instances

MonadError e m => MonadError e (HeistT n m)

MonadError passthrough instance

MonadReader r m => MonadReader r (HeistT n m)

MonadReader passthrough instance

MonadState s m => MonadState s (HeistT n m)

MonadState passthrough instance

MonadTrans (HeistT n)

MonadTrans instance

(Functor m, MonadPlus m) => Alternative (HeistT n m)

Alternative passthrough instance

Monad m => Monad (HeistT n m)

Monad instance

Functor m => Functor (HeistT n m)

Functor instance

MonadFix m => MonadFix (HeistT n m)

MonadFix passthrough instance

MonadPlus m => MonadPlus (HeistT n m)

MonadPlus passthrough instance

(Monad m, Functor m) => Applicative (HeistT n m)

Applicative instance

MonadCatchIO m => MonadCatchIO (HeistT n m)

MonadCatchIO instance

MonadIO m => MonadIO (HeistT n m)

MonadIO instance

MonadCont m => MonadCont (HeistT n m)

MonadCont passthrough instance

Typeable ((* -> *) -> (* -> *) -> * -> *) HeistT 

Lenses (can be used with lens or lens-family)

scInterpretedSplices :: Functor f => (Splices (Splice m) -> f (Splices (Splice m))) -> SpliceConfig m -> f (SpliceConfig m) Source

Lens for interpreted splices :: Simple Lens (SpliceConfig m) (Splices (I.Splice m))

scLoadTimeSplices :: Functor f => (Splices (Splice IO) -> f (Splices (Splice IO))) -> SpliceConfig m -> f (SpliceConfig m) Source

Lens for load time splices :: Simple Lens (SpliceConfig m) (Splices (I.Splice IO))

scCompiledSplices :: Functor f => (Splices (Splice m) -> f (Splices (Splice m))) -> SpliceConfig m -> f (SpliceConfig m) Source

Lens for complied splices :: Simple Lens (SpliceConfig m) (Splices (C.Splice m))

scAttributeSplices :: Functor f => (Splices (AttrSplice m) -> f (Splices (AttrSplice m))) -> SpliceConfig m -> f (SpliceConfig m) Source

Lens for attribute splices :: Simple Lens (SpliceConfig m) (Splices (AttrSplice m))

scTemplateLocations :: Functor f => ([TemplateLocation] -> f [TemplateLocation]) -> SpliceConfig m -> f (SpliceConfig m) Source

Lens for template locations :: Simple Lens (SpliceConfig m) [TemplateLocation]

hcSpliceConfig :: Functor f => (SpliceConfig m -> f (SpliceConfig m)) -> HeistConfig m -> f (HeistConfig m) Source

Lens for the SpliceConfig :: Simple Lens (HeistConfig m) (SpliceConfig m)

hcNamespace :: Functor f => (Text -> f Text) -> HeistConfig m -> f (HeistConfig m) Source

Lens for the namespace :: Simple Lens (HeistConfig m) Text

hcErrorNotBound :: Functor f => (Bool -> f Bool) -> HeistConfig m -> f (HeistConfig m) Source

Lens for the namespace error flag :: Simple Lens (HeistConfig m) Bool

hcInterpretedSplices :: Functor f => (Splices (Splice m) -> f (Splices (Splice m))) -> HeistConfig m -> f (HeistConfig m) Source

Lens for interpreted splices :: Simple Lens (HeistConfig m) (Splices (I.Splice m))

hcLoadTimeSplices :: Functor f => (Splices (Splice IO) -> f (Splices (Splice IO))) -> HeistConfig m -> f (HeistConfig m) Source

Lens for load time splices :: Simple Lens (HeistConfig m) (Splices (I.Splice IO))

hcCompiledSplices :: Functor f => (Splices (Splice m) -> f (Splices (Splice m))) -> HeistConfig m -> f (HeistConfig m) Source

Lens for compiled splices :: Simple Lens (HeistConfig m) (Splices (C.Splice m))

hcAttributeSplices :: Functor f => (Splices (AttrSplice m) -> f (Splices (AttrSplice m))) -> HeistConfig m -> f (HeistConfig m) Source

Lens for attribute splices :: Simple Lens (HeistConfig m) (Splices (AttrSplice m))

hcTemplateLocations :: Functor f => ([TemplateLocation] -> f [TemplateLocation]) -> HeistConfig m -> f (HeistConfig m) Source

Lens for template locations :: Simple Lens (HeistConfig m) [TemplateLocation]

HeistT functions

templateNames :: HeistState m -> [TPath] Source

Gets the names of all the templates defined in a HeistState.

compiledTemplateNames :: HeistState m -> [TPath] Source

Gets the names of all the templates defined in a HeistState.

hasTemplate :: ByteString -> HeistState n -> Bool Source

Returns True if the given template can be found in the heist state.

spliceNames :: HeistState m -> [Text] Source

Gets the names of all the interpreted splices defined in a HeistState.

compiledSpliceNames :: HeistState m -> [Text] Source

Gets the names of all the compiled splices defined in a HeistState.

evalHeistT :: Monad m => HeistT n m a -> Node -> HeistState n -> m a Source

Evaluates a template monad as a computation in the underlying monad.

getParamNode :: Monad m => HeistT n m Node Source

Gets the node currently being processed.

<speech author="Shakespeare">
  To sleep, perchance to dream.
</speech>

When you call getParamNode inside the code for the speech splice, it returns the Node for the speech tag and its children. getParamNode >>= childNodes returns a list containing one TextNode containing part of Hamlet's speech. liftM (getAttribute "author") getParamNode would return Just Shakespeare.

getContext :: Monad m => HeistT n m TPath Source

Gets the current context

getTemplateFilePath :: Monad m => HeistT n m (Maybe FilePath) Source

Gets the full path to the file holding the template currently being processed. Returns Nothing if the template is not associated with a file on disk or if there is no template being processed.

localParamNode :: Monad m => (Node -> Node) -> HeistT n m a -> HeistT n m a Source

HeistT's local.

getsHS :: Monad m => (HeistState n -> r) -> HeistT n m r Source

HeistT's gets.

getHS :: Monad m => HeistT n m (HeistState n) Source

HeistT's get.

putHS :: Monad m => HeistState n -> HeistT n m () Source

HeistT's put.

modifyHS :: Monad m => (HeistState n -> HeistState n) -> HeistT n m () Source

HeistT's modify.

restoreHS :: Monad m => HeistState n -> HeistT n m () Source

Restores the HeistState. This function is almost like putHS except it preserves the current doctypes. You should use this function instead of putHS to restore an old state. This was needed because doctypes needs to be in a "global scope" as opposed to the template call "local scope" of state items such as recursionDepth, curContext, and spliceMap.

localHS :: Monad m => (HeistState n -> HeistState n) -> HeistT n m a -> HeistT n m a Source

Abstracts the common pattern of running a HeistT computation with a modified heist state.

getDoc :: String -> IO (Either String DocumentFile) Source

Reads an HTML template from disk.

getXMLDoc :: String -> IO (Either String DocumentFile) Source

Reads an XML template from disk.

tellSpliceError :: Monad m => Text -> HeistT n m () Source

Adds an error message to the list of splice processing errors.

orError :: Monad m => HeistT n m b -> String -> HeistT n m b Source

If Heist is running in fail fast mode, then this function will throw an exception with the second argument as the error message. Otherwise, the first argument will be executed to represent silent failure.

This behavior allows us to fail quickly if an error crops up during load-time splice processing or degrade more gracefully if the error occurs while a user request is being processed.