Copyright | © 2016–2017 Stack Builders |
---|---|
License | BSD 3 clause |
Maintainer | Mark Karpov <markkarpov@openmailbox.org> |
Stability | experimental |
Portability | portable |
Safe Haskell | None |
Language | Haskell2010 |
Text.Microstache
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.
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 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.Microstache.Compile.TH module. The helpers are currently available only for GHC 8 users though.
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.Microstache 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 -> print 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 {}
- data MustacheException
- displayMustacheException :: MustacheException -> String
- data MustacheWarning
- displayMustacheWarning :: MustacheWarning -> String
- compileMustacheDir :: PName -> FilePath -> IO Template
- compileMustacheFile :: FilePath -> IO Template
- compileMustacheText :: PName -> Text -> Either ParseError 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 Template
s
(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
Data Template # | |||||
Defined in Text.Microstache.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 :: forall r r'. (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 # | |||||
Semigroup Template # | |||||
Generic Template # | |||||
Defined in Text.Microstache.Type Associated Types
| |||||
Show Template # | |||||
Eq Template # | |||||
Ord Template # | |||||
Defined in Text.Microstache.Type | |||||
type Rep Template # | |||||
Defined in Text.Microstache.Type type Rep Template = D1 ('MetaData "Template" "Text.Microstache.Type" "microstache-1.0.2.3-DwZkw7U9d9640vqKYO1sOg" '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 Word) | 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
Data Key # | |||||
Defined in Text.Microstache.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 :: forall r r'. (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 # | |||||
Monoid Key # | |||||
Semigroup Key # | |||||
Generic Key # | |||||
Defined in Text.Microstache.Type Associated Types
| |||||
Show Key # | |||||
NFData Key # | |||||
Defined in Text.Microstache.Type | |||||
Eq Key # | |||||
Ord Key # | |||||
type Rep Key # | |||||
Defined in Text.Microstache.Type |
Identifier for partials. Note that with the OverloadedStrings
extension you can use just string literals to create values of this type.
Instances
Data PName # | |||||
Defined in Text.Microstache.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 :: forall r r'. (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 # | |||||
IsString PName # | |||||
Defined in Text.Microstache.Type Methods fromString :: String -> PName # | |||||
Generic PName # | |||||
Defined in Text.Microstache.Type Associated Types
| |||||
Show PName # | |||||
NFData PName # | |||||
Defined in Text.Microstache.Type | |||||
Eq PName # | |||||
Ord PName # | |||||
type Rep PName # | |||||
Defined in Text.Microstache.Type |
data MustacheException #
Exception that is thrown when parsing of a template has failed or referenced values were not provided.
Constructors
MustacheParserException ParseError | Template parser has failed. This contains the parse error. |
MustacheRenderException PName Key | Deprecated: Not thrown anymore, will be removed in the next major version of microstache A referenced value was not provided. The exception provides info
about partial in which the issue happened |
Instances
Exception MustacheException # | |||||
Defined in Text.Microstache.Type Methods toException :: MustacheException -> SomeException # | |||||
Generic MustacheException # | |||||
Defined in Text.Microstache.Type Associated Types
Methods from :: MustacheException -> Rep MustacheException x # to :: Rep MustacheException x -> MustacheException # | |||||
Show MustacheException # | |||||
Defined in Text.Microstache.Type Methods showsPrec :: Int -> MustacheException -> ShowS # show :: MustacheException -> String # showList :: [MustacheException] -> ShowS # | |||||
Eq MustacheException # | |||||
Defined in Text.Microstache.Type Methods (==) :: MustacheException -> MustacheException -> Bool # (/=) :: MustacheException -> MustacheException -> Bool # | |||||
type Rep MustacheException # | |||||
Defined in Text.Microstache.Type type Rep MustacheException = D1 ('MetaData "MustacheException" "Text.Microstache.Type" "microstache-1.0.2.3-DwZkw7U9d9640vqKYO1sOg" 'False) (C1 ('MetaCons "MustacheParserException" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ParseError)) :+: C1 ('MetaCons "MustacheRenderException" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 PName) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Key))) |
displayMustacheException :: MustacheException -> String #
Since: 1.0.1
data MustacheWarning #
Since: 1.0.1
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 Object or Array was directly rendered into the template |
Instances
Exception MustacheWarning # | |||||
Defined in Text.Microstache.Type Methods toException :: MustacheWarning -> SomeException # | |||||
Generic MustacheWarning # | |||||
Defined in Text.Microstache.Type Associated Types
Methods from :: MustacheWarning -> Rep MustacheWarning x # to :: Rep MustacheWarning x -> MustacheWarning # | |||||
Show MustacheWarning # | |||||
Defined in Text.Microstache.Type Methods showsPrec :: Int -> MustacheWarning -> ShowS # show :: MustacheWarning -> String # showList :: [MustacheWarning] -> ShowS # | |||||
Eq MustacheWarning # | |||||
Defined in Text.Microstache.Type Methods (==) :: MustacheWarning -> MustacheWarning -> Bool # (/=) :: MustacheWarning -> MustacheWarning -> Bool # | |||||
type Rep MustacheWarning # | |||||
Defined in Text.Microstache.Type type Rep MustacheWarning = D1 ('MetaData "MustacheWarning" "Text.Microstache.Type" "microstache-1.0.2.3-DwZkw7U9d9640vqKYO1sOg" 'False) (C1 ('MetaCons "MustacheVariableNotFound" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Key)) :+: C1 ('MetaCons "MustacheDirectlyRenderedValue" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Key))) |
displayMustacheWarning :: MustacheWarning -> String #
Since: 1.0.1
Compiling
Arguments
:: PName | Which template to select after compiling |
-> FilePath | Directory with templates |
-> IO Template | The resulting template |
Compile all templates in specified directory and select one. Template
files should have 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
.
Compile single Mustache template and select it.
The action can throw the same exceptions as readFile
.
Arguments
:: PName | How to name the template? |
-> Text | The template to compile |
-> Either ParseError Template | The result |
Rendering
renderMustache :: Template -> Value -> Text #
renderMustacheW :: Template -> Value -> ([MustacheWarning], Text) #
Like renderMustache
but also return a list of warnings.
Since: 1.0.1