| Copyright | © 2016–2018 Stack Builders |
|---|---|
| License | BSD 3 clause |
| Maintainer | Mark Karpov <markkarpov92@gmail.com> |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Text.Mustache
Description
This is a Haskell implementation of Mustache templates. The implementation conforms to the version 1.1.3 of official Mustache specification https://github.com/mustache/spec. It is extremely simple and straightforward to use with minimal but complete API—three functions to compile templates (from directory, from file, and from lazy text) and one to render them.
The implementation uses Megaparsec parsing library to parse the templates which results in superior quality of error messages.
For rendering you only need to create Aeson's Value where
you put the data to interpolate. Since the library re-uses Aeson's
instances and most data types in the Haskell ecosystem are instances of
classes like ToJSON, the whole process is very simple for
the end user.
Template Haskell helpers for compilation of templates at compile time are available in the Text.Mustache.Compile.TH module. The helpers currently work only with GHC 8 and later.
One feature that is not currently supported is lambdas. The feature is marked as optional in the spec and can be emulated via processing of parsed template representation. The decision to drop lambdas is intentional, for the sake of simplicity and better integration with Aeson.
Here is an example of basic usage:
{-# LANGUAGE OverloadedStrings #-}
module Main (main) where
import Data.Aeson
import Data.Text
import Text.Megaparsec
import Text.Mustache
import qualified Data.Text.Lazy.IO as TIO
main :: IO ()
main = do
let res = compileMustacheText "foo"
"Hi, {{name}}! You have:\n{{#things}}\n * {{.}}\n{{/things}}\n"
case res of
Left err -> putStrLn (parseErrorPretty err)
Right template -> TIO.putStr $ renderMustache template $ object
[ "name" .= ("John" :: Text)
, "things" .= ["pen" :: Text, "candle", "egg"]
]If I run the program, it prints the following:
Hi, John! You have: * pen * candle * egg
For more information about Mustache templates the following links may be helpful:
- The official Mustache site: https://mustache.github.io/
- The manual: https://mustache.github.io/mustache.5.html
- The specification: https://github.com/mustache/spec
- Stack Builders Stache tutorial: https://www.stackbuilders.com/tutorials/haskell/mustache-templates/
Synopsis
- data Template = Template {
- templateActual :: PName
- templateCache :: Map PName [Node]
- data Node
- newtype Key = Key {}
- newtype PName = PName {}
- newtype MustacheException = MustacheParserException (ParseErrorBundle Text Void)
- data MustacheWarning
- displayMustacheWarning :: MustacheWarning -> String
- compileMustacheDir :: MonadIO m => PName -> FilePath -> m Template
- compileMustacheDir' :: MonadIO m => (FilePath -> Bool) -> PName -> FilePath -> m Template
- compileMustacheFile :: MonadIO m => FilePath -> m Template
- compileMustacheText :: PName -> Text -> Either (ParseErrorBundle Text Void) Template
- renderMustache :: Template -> Value -> Text
- renderMustacheW :: Template -> Value -> ([MustacheWarning], Text)
Types
Mustache template as name of “top-level” template and a collection of all available templates (partials).
Template is a Semigroup. This means that you can combine Templates
(and their caches) using the ( operator, the resulting <>)Template
will have the same currently selected template as the left one. Union of
caches is also left-biased.
Constructors
| Template | |
Fields
| |
Instances
| Eq Template Source # | |
| Data Template Source # | |
Defined in Text.Mustache.Type Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Template -> c Template # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Template # toConstr :: Template -> Constr # dataTypeOf :: Template -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Template) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Template) # gmapT :: (forall b. Data b => b -> b) -> Template -> Template # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Template -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Template -> r # gmapQ :: (forall d. Data d => d -> u) -> Template -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Template -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Template -> m Template # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Template -> m Template # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Template -> m Template # | |
| Ord Template Source # | |
Defined in Text.Mustache.Type | |
| Show Template Source # | |
| Generic Template Source # | |
| Semigroup Template Source # | |
| type Rep Template Source # | |
Defined in Text.Mustache.Type type Rep Template = D1 (MetaData "Template" "Text.Mustache.Type" "stache-2.0.1-vTB2MDeGKkIHNgjuvknyy" False) (C1 (MetaCons "Template" PrefixI True) (S1 (MetaSel (Just "templateActual") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 PName) :*: S1 (MetaSel (Just "templateCache") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Map PName [Node])))) | |
Structural element of template.
Constructors
| TextBlock Text | Plain text contained between tags |
| EscapedVar Key | HTML-escaped variable |
| UnescapedVar Key | Unescaped variable |
| Section Key [Node] | Mustache section |
| InvertedSection Key [Node] | Inverted section |
| Partial PName (Maybe Pos) | Partial with indentation level ( |
Instances
Identifier for values to interpolate.
The representation is the following:
[]—empty list means implicit iterators;[text]—single key is a normal identifier;[text1, text2]—multiple keys represent dotted names.
Instances
| Eq Key Source # | |
| Data Key Source # | |
Defined in Text.Mustache.Type Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Key -> c Key # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Key # dataTypeOf :: Key -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Key) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Key) # gmapT :: (forall b. Data b => b -> b) -> Key -> Key # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Key -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Key -> r # gmapQ :: (forall d. Data d => d -> u) -> Key -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Key -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Key -> m Key # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Key -> m Key # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Key -> m Key # | |
| Ord Key Source # | |
| Show Key Source # | |
| Generic Key Source # | |
| Semigroup Key Source # | |
| Monoid Key Source # | |
| NFData Key Source # | |
Defined in Text.Mustache.Type | |
| type Rep Key Source # | |
Defined in Text.Mustache.Type | |
Identifier for partials. Note that with the OverloadedStrings
extension you can use just string literals to create values of this type.
Instances
| Eq PName Source # | |
| Data PName Source # | |
Defined in Text.Mustache.Type Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> PName -> c PName # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c PName # dataTypeOf :: PName -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c PName) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PName) # gmapT :: (forall b. Data b => b -> b) -> PName -> PName # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> PName -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> PName -> r # gmapQ :: (forall d. Data d => d -> u) -> PName -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> PName -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> PName -> m PName # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> PName -> m PName # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> PName -> m PName # | |
| Ord PName Source # | |
| Show PName Source # | |
| IsString PName Source # | |
Defined in Text.Mustache.Type Methods fromString :: String -> PName # | |
| Generic PName Source # | |
| NFData PName Source # | |
Defined in Text.Mustache.Type | |
| type Rep PName Source # | |
Defined in Text.Mustache.Type | |
newtype MustacheException Source #
Exception that is thrown when parsing of a template fails or referenced values are not provided.
Constructors
| MustacheParserException (ParseErrorBundle Text Void) | Template parser has failed. This contains the parse error. Before version 0.2.0 it was called The |
Instances
data MustacheWarning Source #
Warning that may be generated during rendering of a Template.
Since: stache-1.1.1
Constructors
| MustacheVariableNotFound Key | The template contained a variable for which there was no data counterpart in the current context. |
| MustacheDirectlyRenderedValue Key | A complex value such as an |
Instances
displayMustacheWarning :: MustacheWarning -> String Source #
Pretty-print a MustacheWarning.
Since: stache-1.1.1
Compiling
Arguments
| :: MonadIO m | |
| => PName | Which template to select after compiling |
| -> FilePath | Directory with templates |
| -> m Template | The resulting template |
Compile all templates in specified directory and select one. Template
files should have the extension mustache, (e.g. foo.mustache) to be
recognized. This function does not scan the directory recursively.
The action can throw the same exceptions as getDirectoryContents, and
readFile.
compileMustacheDir = complieMustacheDir' isMustacheFile
Arguments
| :: MonadIO m | |
| => (FilePath -> Bool) | Template selection predicate |
| -> PName | Which template to select after compiling |
| -> FilePath | Directory with templates |
| -> m Template | The resulting template |
The same as compileMustacheDir, but allows using a custom predicate
for template selection.
Since: stache-1.2.0
Compile a single Mustache template and select it.
The action can throw the same exceptions as readFile.
Rendering
renderMustacheW :: Template -> Value -> ([MustacheWarning], Text) Source #
Like renderMustache, but also returns a collection of warnings.
Since: stache-1.1.1