| Safe Haskell | None |
|---|---|
| Language | Haskell98 |
Heist.Interpreted
Description
This module defines the API for writing and working with interpreted splices. It exports some of the same symbols as Heist.Compiled, so you will probably want to import it qualified.
Interpreted splices can be thought of as a function Node -> m [Node]. Heist
then substitutes the resulting list of nodes into your template in place of
the input node. Splice is implemented as a type synonym type Splice m =
HeistT m [Node], and HeistT has a function getParamNode that lets you get
the input node.
Suppose you have a place on your page where you want to display a link with
the text "Logout username" if the user is currently logged in or a link to
the login page if no user is logged in. Assume you have a function
getUser :: MyAppMonad (Maybe Text) that gets the current user.
You can implement this functionality with a Splice as follows:
import Blaze.ByteString.Builder
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B
import Data.Text (Text)
import qualified Data.Text as T
import qualified Text.XmlHtml as X
import qualified Heist.Interpreted as I
link :: Text -> Text -> X.Node
link target text = X.Element "a" [("href", target)] [X.TextNode text]
loginLink :: X.Node
loginLink = link "/login" "Login"
logoutLink :: Text -> X.Node
logoutLink user = link "/logout" (T.append "Logout " user)
loginLogoutSplice :: I.Splice MyAppMonad
loginLogoutSplice = do
user <- lift getUser
return [maybe loginLink logoutLink user]
- type Splice n = HeistT n n Template
- addTemplate :: ByteString -> Template -> Maybe FilePath -> HeistState n -> HeistState n
- addXMLTemplate :: ByteString -> Template -> Maybe FilePath -> HeistState n -> HeistState n
- lookupSplice :: Text -> HeistState n -> Maybe (Splice n)
- bindSplice :: Text -> Splice n -> HeistState n -> HeistState n
- bindSplices :: Splices (Splice n) -> HeistState n -> HeistState n
- bindAttributeSplices :: Splices (AttrSplice n) -> HeistState n -> HeistState n
- textSplice :: Monad m => Text -> HeistT n m Template
- runChildren :: Monad n => Splice n
- runChildrenWith :: Monad n => Splices (Splice n) -> Splice n
- runChildrenWithTrans :: Monad n => (b -> Splice n) -> Splices b -> Splice n
- runChildrenWithTemplates :: Monad n => Splices Template -> Splice n
- runChildrenWithText :: Monad n => Splices Text -> Splice n
- mapSplices :: (Monad m, Monoid b) => (a -> m b) -> [a] -> m b
- stopRecursion :: Monad m => HeistT n m ()
- runNode :: Monad n => Node -> Splice n
- runAttributes :: Monad n => [(Text, Text)] -> HeistT n n [(Text, Text)]
- runNodeList :: Monad n => [Node] -> Splice n
- evalTemplate :: Monad n => ByteString -> HeistT n n (Maybe Template)
- bindStrings :: Monad n => Splices Text -> HeistState n -> HeistState n
- bindString :: Monad n => Text -> Text -> HeistState n -> HeistState n
- callTemplate :: Monad n => ByteString -> Splices (Splice n) -> HeistT n n Template
- callTemplateWithText :: Monad n => ByteString -> Splices Text -> HeistT n n Template
- renderTemplate :: Monad n => HeistState n -> ByteString -> n (Maybe (Builder, MIMEType))
- renderWithArgs :: Monad n => Splices Text -> HeistState n -> ByteString -> n (Maybe (Builder, MIMEType))
Documentation
HeistState Functions
Arguments
| :: ByteString | Path that the template will be referenced by |
| -> Template | The template's DOM nodes |
| -> Maybe FilePath | An optional path to the actual file on disk where the template is stored |
| -> HeistState n | |
| -> HeistState n |
Adds an HTML format template to the heist state.
Arguments
| :: ByteString | Path that the template will be referenced by |
| -> Template | The template's DOM nodes |
| -> Maybe FilePath | An optional path to the actual file on disk where the template is stored |
| -> HeistState n | |
| -> HeistState n |
Adds an XML format template to the heist state.
lookupSplice :: Text -> HeistState n -> Maybe (Splice n) Source
Convenience function for looking up a splice.
Arguments
| :: Text | tag name |
| -> Splice n | splice action |
| -> HeistState n | source state |
| -> HeistState n |
Binds a new splice declaration to a tag name within a HeistState.
Arguments
| :: Splices (Splice n) | splices to bind |
| -> HeistState n | start state |
| -> HeistState n |
Binds a set of new splice declarations within a HeistState.
Arguments
| :: Splices (AttrSplice n) | splices to bind |
| -> HeistState n | start state |
| -> HeistState n |
Binds a set of new splice declarations within a HeistState.
Functions for creating splices
textSplice :: Monad m => Text -> HeistT n m Template Source
Converts Text to a splice returning a single TextNode.
runChildren :: Monad n => Splice n Source
Runs the parameter node's children and returns the resulting node list. By itself this function is a simple passthrough splice that makes the spliced node disappear. In combination with locally bound splices, this function makes it easier to pass the desired view into your splices.
Arguments
| :: Monad n | |
| => Splices (Splice n) | List of splices to bind before running the param nodes. |
| -> Splice n | Returns the passed in view. |
Binds a list of splices before using the children of the spliced node as a view.
Arguments
| :: Monad n | |
| => (b -> Splice n) | Splice generating function |
| -> Splices b | List of tuples to be bound |
| -> Splice n |
Wrapper around runChildrenWith that applies a transformation function to the second item in each of the tuples before calling runChildrenWith.
runChildrenWithTemplates :: Monad n => Splices Template -> Splice n Source
Like runChildrenWith but using constant templates rather than dynamic splices.
runChildrenWithText :: Monad n => Splices Text -> Splice n Source
Like runChildrenWith but using literal text rather than dynamic splices.
Arguments
| :: (Monad m, Monoid b) | |
| => (a -> m b) | Splice generating function |
| -> [a] | List of items to generate splices for |
| -> m b | The result of all splices concatenated together. |
Maps a splice generating function over a list and concatenates the results. This function now has a more general type signature so it works with both compiled and interpreted splices. The old type signature was this:
mapSplices :: (Monad n)
=> (a -> Splice n n)
-> [a]
-> Splice n nHeistT functions
stopRecursion :: Monad m => HeistT n m () Source
Stops the recursive processing of splices. Consider the following example:
<foo>
<bar>
...
</bar>
</foo>Assume that "foo" is bound to a splice procedure. Running the foo
splice will result in a list of nodes L. Normally foo will recursively
scan L for splices and run them. If foo calls stopRecursion, L
will be included in the output verbatim without running any splices.
runAttributes :: Monad n => [(Text, Text)] -> HeistT n n [(Text, Text)] Source
Performs splice processing on a list of attributes. This is useful in situations where you need to stop recursion, but still run splice processing on the node's attributes.
runNodeList :: Monad n => [Node] -> Splice n Source
Performs splice processing on a list of nodes.
evalTemplate :: Monad n => ByteString -> HeistT n n (Maybe Template) Source
Looks up a template name evaluates it by calling runNodeList.
bindStrings :: Monad n => Splices Text -> HeistState n -> HeistState n Source
Binds a list of constant string splices.
bindString :: Monad n => Text -> Text -> HeistState n -> HeistState n Source
Binds a single constant string splice.
Arguments
| :: Monad n | |
| => ByteString | The name of the template |
| -> Splices (Splice n) | Splices to call the template with |
| -> HeistT n n Template |
Renders a template with the specified parameters. This is the function to use when you want to "call" a template and pass in parameters from inside a splice. If the template does not exist, this version simply returns an empty list.
Arguments
| :: Monad n | |
| => ByteString | The name of the template |
| -> Splices Text | Splices to call the template with |
| -> HeistT n n Template |
Like callTemplate except the splices being bound are constant text splices.
renderTemplate :: Monad n => HeistState n -> ByteString -> n (Maybe (Builder, MIMEType)) Source
Renders a template from the specified HeistState to a Builder. The
MIME type returned is based on the detected character encoding, and whether
the root template was an HTML or XML format template. It will always be
text/html or text/xml. If a more specific MIME type is needed for a
particular XML application, it must be provided by the application.
renderWithArgs :: Monad n => Splices Text -> HeistState n -> ByteString -> n (Maybe (Builder, MIMEType)) Source
Renders a template with the specified arguments passed to it. This is a convenience function for the common pattern of calling renderTemplate after using bindString, bindStrings, or bindSplice to set up the arguments to the template.