| Portability | portable |
|---|---|
| Stability | experimental |
| Maintainer | s.clover@gmail.com |
| Safe Haskell | Safe-Infered |
Text.StringTemplate
Description
A StringTemplate is a String with "holes" in it. This is a port of the Java StringTemplate library written by Terrence Parr. (http://www.stringtemplate.org). User-contributed documentation available at http://www.haskell.org/haskellwiki/HStringTemplate.
This library implements the basic 3.1 grammar, lacking group files (though not groups themselves), Regions, and Interfaces. The goal is not to blindly copy the StringTemplate API, but rather to take its central ideas and implement them in a Haskellish manner. Indentation and wrapping, for example, are implemented through the HughesPJ Pretty Printing library. Calling toPPDoc on a StringTemplate yields a Doc with appropriate paragraph-fill wrapping that can be rendered in the usual fashion.
Basic instances are provided of the StringTemplateShows and ToSElem class.
Any type deriving ToSElem can be passed automatically as a StringTemplate
attribute. This package can be installed with syb-with-class bindings
that provide a ToSElem instance for anything deriving
Data. When defining an instance of
ToSElem that can take a format parameter, you should first define an
instance of StringTemplateShows, and then define an instance of ToSElem
where toSElem = stShowsToSE.
- data StringTemplate a
- type STGroup a = String -> StFirst (StringTemplate a)
- class ToSElem a where
- toSElem :: Stringable b => a -> SElem b
- toSElemList :: Stringable b => [a] -> SElem b
- class Show a => StringTemplateShows a where
- stringTemplateShow :: a -> String
- stringTemplateFormattedShow :: String -> a -> String
- stShowsToSE :: (StringTemplateShows a, Stringable b) => a -> SElem b
- class Stringable a where
- stFromString :: String -> a
- stFromByteString :: ByteString -> a
- stToString :: a -> String
- mconcatMap :: [b] -> (b -> a) -> a
- mintercalate :: a -> [a] -> a
- mlabel :: a -> a -> a
- smempty :: a
- smappend :: a -> a -> a
- smconcat :: [a] -> a
- class Stringable b => SEType b a where
- renderf :: StringTemplate b -> a
- newSTMP :: Stringable a => String -> StringTemplate a
- newAngleSTMP :: Stringable a => String -> StringTemplate a
- getStringTemplate :: Stringable a => String -> STGroup a -> Maybe (StringTemplate a)
- getStringTemplate' :: Stringable a => String -> STGroup a -> Maybe (StringTemplate a)
- toString :: StringTemplate String -> String
- toPPDoc :: StringTemplate Doc -> Doc
- render :: Stringable a => StringTemplate a -> a
- dumpAttribs :: Stringable a => StringTemplate a
- checkTemplate :: Stringable a => StringTemplate a -> (Maybe String, Maybe [String], Maybe [String])
- checkTemplateDeep :: (Stringable a, NFData a) => StringTemplate a -> ([(String, String)], [String], [String])
- setAttribute :: (ToSElem a, Stringable b) => String -> a -> StringTemplate b -> StringTemplate b
- (|=) :: Monad m => a -> m a1 -> m (a, a1)
- setManyAttrib :: (ToSElem a, Stringable b) => [(String, a)] -> StringTemplate b -> StringTemplate b
- setNativeAttribute :: Stringable b => String -> b -> StringTemplate b -> StringTemplate b
- setManyNativeAttrib :: Stringable b => [(String, b)] -> StringTemplate b -> StringTemplate b
- withContext :: (ToSElem a, Stringable b) => StringTemplate b -> a -> StringTemplate b
- optInsertTmpl :: [(String, String)] -> StringTemplate a -> StringTemplate a
- optInsertGroup :: [(String, String)] -> STGroup a -> STGroup a
- setEncoder :: Stringable a => (a -> a) -> StringTemplate a -> StringTemplate a
- setEncoderGroup :: Stringable a => (a -> a) -> STGroup a -> STGroup a
- groupStringTemplates :: [(String, StringTemplate a)] -> STGroup a
- addSuperGroup :: STGroup a -> STGroup a -> STGroup a
- addSubGroup :: STGroup a -> STGroup a -> STGroup a
- mergeSTGroups :: STGroup a -> STGroup a -> STGroup a
- directoryGroup :: Stringable a => FilePath -> IO (STGroup a)
- unsafeVolatileDirectoryGroup :: Stringable a => FilePath -> Int -> IO (STGroup a)
- directoryGroupRecursive :: Stringable a => FilePath -> IO (STGroup a)
- directoryGroupRecursiveLazy :: Stringable a => FilePath -> IO (STGroup a)
- directoryGroupLazy :: Stringable a => FilePath -> IO (STGroup a)
- nullGroup :: Stringable a => STGroup a
Types
data StringTemplate a
A String with "holes" in it. StringTemplates may be composed of any
Stringable type, which at the moment includes Strings, ByteStrings,
PrettyPrinter Docs, and Endo Strings, which are actually of type
ShowS. When a StringTemplate is composed of a type, its internals are
as well, so it is, so to speak "turtles all the way down."
Instances
| Stringable a => SEType a (StringTemplate a) |
type STGroup a = String -> StFirst (StringTemplate a)
A function that generates StringTemplates. This is conceptually a query function into a "group" of StringTemplates.
Classes
class ToSElem a where
The ToSElem class should be instantiated for all types that can be inserted as attributes into a StringTemplate.
Instances
class Show a => StringTemplateShows a where
The StringTemplateShows class should be instantiated for all types that are directly displayed in a StringTemplate, but take an optional format string. Each such type must have an appropriate ToSElem method defined as well.
Methods
stringTemplateShow :: a -> String
Defaults to show.
stringTemplateFormattedShow :: String -> a -> String
Defaults to _ a -> stringTemplateShow a
stShowsToSE :: (StringTemplateShows a, Stringable b) => a -> SElem b
This method should be used to create ToSElem instances for types defining a custom formatted show function.
class Stringable a where
The Stringable class should be instantiated with care. Generally, the provided instances should be enough for anything.
Methods
stFromString :: String -> a
stFromByteString :: ByteString -> a
stToString :: a -> String
mconcatMap :: [b] -> (b -> a) -> a
Defaults to mconcatMap m k = foldr (mappend . k) mempty m
mintercalate :: a -> [a] -> a
Defaults to (mconcat .) . intersperse
mlabel :: a -> a -> a
smempty :: a
Just mempty. Here to avoid orphan instances
smappend :: a -> a -> a
Just mappend. Here to avoid orphan instances
smconcat :: [a] -> a
Just mconcat. Here to avoid orphan instances
class Stringable b => SEType b a where
Methods
renderf :: StringTemplate b -> a
Instances
| Stringable a => SEType a a | |
| Stringable a => SEType a (StringTemplate a) | |
| (ToSElem a, SEType b r) => SEType b ((String, a) -> r) |
Creation
newSTMP :: Stringable a => String -> StringTemplate a
Parses a String to produce a StringTemplate, with '$'s as delimiters. It is constructed with a stub group that cannot look up other templates.
newAngleSTMP :: Stringable a => String -> StringTemplate a
Parses a String to produce a StringTemplate, delimited by angle brackets. It is constructed with a stub group that cannot look up other templates.
getStringTemplate :: Stringable a => String -> STGroup a -> Maybe (StringTemplate a)
Queries an String Template Group and returns Just the appropriate StringTemplate if it exists, otherwise, Nothing.
getStringTemplate' :: Stringable a => String -> STGroup a -> Maybe (StringTemplate a)
As with getStringTemplate but never inlined, so appropriate for use
with volatile template groups.
Display
toString :: StringTemplate String -> String
Renders a StringTemplate to a String.
toPPDoc :: StringTemplate Doc -> Doc
Renders a StringTemplate to a Doc.
render :: Stringable a => StringTemplate a -> a
Generic render function for a StringTemplate of any type.
dumpAttribs :: Stringable a => StringTemplate a
A special template that simply dumps the values of all the attributes set in it.
This may be made available to any template as a function by adding it to its group.
I.e. myNewGroup = addSuperGroup myGroup $ groupStringTemplates [(dumpAttribs, dumpAttribs)]
checkTemplate :: Stringable a => StringTemplate a -> (Maybe String, Maybe [String], Maybe [String])
Returns a tuple of three Maybes. The first is set if there is a parse error in the template. The next is set to a list of attributes that have not been set, or Nothing if all attributes are set. The last is set to a list of invoked templates that cannot be looked up, or Nothing if all invoked templates can be found. Note that this check is shallow -- i.e. missing attributes and templates are only caught in the top level template, not any invoked subtemplate.
checkTemplateDeep :: (Stringable a, NFData a) => StringTemplate a -> ([(String, String)], [String], [String])
Returns a tuple of three lists. The first is of templates with parse errors, and their erros. The next is of missing attributes, and the last is of missing templates. If there are no errors, then all lists will be empty.
Modification
setAttribute :: (ToSElem a, Stringable b) => String -> a -> StringTemplate b -> StringTemplate b
Yields a StringTemplate with the appropriate attribute set. If the attribute already exists, it is appended to a list.
setManyAttrib :: (ToSElem a, Stringable b) => [(String, a)] -> StringTemplate b -> StringTemplate b
Yields a StringTemplate with the appropriate attributes set. If any attribute already exists, it is appended to a list.
setNativeAttribute :: Stringable b => String -> b -> StringTemplate b -> StringTemplate b
Yields a StringTemplate with the appropriate attribute set. If the attribute already exists, it is appended to a list. This will not translate the attribute through any intermediate representation, so is more efficient when, e.g. setting attributes that are large bytestrings in a bytestring template.
setManyNativeAttrib :: Stringable b => [(String, b)] -> StringTemplate b -> StringTemplate b
Yields a StringTemplate with the appropriate attributes set. If any attribute already exists, it is appended to a list. Attributes are added natively, which may provide efficiency gains.
withContext :: (ToSElem a, Stringable b) => StringTemplate b -> a -> StringTemplate b
Replaces the attributes of a StringTemplate with those described in the second argument. If the argument does not yield a set of named attributes but only a single one, that attribute is named, as a default, "it".
optInsertTmpl :: [(String, String)] -> StringTemplate a -> StringTemplate a
Adds a set of global options to a single template
optInsertGroup :: [(String, String)] -> STGroup a -> STGroup a
Adds a set of global options to a group
setEncoder :: Stringable a => (a -> a) -> StringTemplate a -> StringTemplate a
Sets an encoding function of a template that all values are
rendered with. For example one useful encoder would be stringToHtmlString. All attributes will be encoded once and only once.
setEncoderGroup :: Stringable a => (a -> a) -> STGroup a -> STGroup a
Sets an encoding function of a group that all values are rendered with in each enclosed template
Groups
groupStringTemplates :: [(String, StringTemplate a)] -> STGroup a
Given a list of named of StringTemplates, returns a group which generates them such that they can call one another.
addSuperGroup :: STGroup a -> STGroup a -> STGroup a
Adds a supergroup to any StringTemplate group such that templates from the original group are now able to call ones from the supergroup as well.
addSubGroup :: STGroup a -> STGroup a -> STGroup a
Adds a "subgroup" to any StringTemplate group such that templates from the original group now have template calls "shadowed" by the subgroup.
mergeSTGroups :: STGroup a -> STGroup a -> STGroup a
Merges two groups into a single group. This function is left-biased, prefering bindings from the first group when there is a conflict.
directoryGroup :: Stringable a => FilePath -> IO (STGroup a)
Given a path, returns a group which generates all files in said directory which have the proper "st" extension. This function is strict, with all files read once. As it performs file IO, expect it to throw the usual exceptions.
unsafeVolatileDirectoryGroup :: Stringable a => FilePath -> Int -> IO (STGroup a)
Given an integral amount of seconds and a path, returns a group generating all files in said directory and subdirectories with the proper "st" extension, cached for that amount of seconds. IO errors are "swallowed" by this so that exceptions don't arise in unexpected places. This violates referential transparency, but can be very useful in developing templates for any sort of server application. It should be swapped out for production purposes. The dumpAttribs template is added to the returned group by default, as it should prove useful for debugging and developing templates.
directoryGroupRecursive :: Stringable a => FilePath -> IO (STGroup a)
As with directoryGroup, but traverses subdirectories as well. A template named
"foobar.st\" may be referenced by \"foobar" in the returned group.
directoryGroupRecursiveLazy :: Stringable a => FilePath -> IO (STGroup a)
See documentation for directoryGroupRecursive.
directoryGroupLazy :: Stringable a => FilePath -> IO (STGroup a)
Given a path, returns a group which generates all files in said directory which have the proper "st" extension. This function is lazy in the same way that readFile is lazy, with all files read on demand, but no more than once. The list of files, however, is generated at the time the function is called. As this performs file IO, expect it to throw the usual exceptions. And, as it is lazy, expect these exceptions in unexpected places.
nullGroup :: Stringable a => STGroup a
For any requested template, returns a message that the template was unable to be found. Useful to add as a super group for a set of templates under development, to aid in debugging.