Language.Haskell.TH.QuasiQuoter

Safe Haskell	Safe
Language	Haskell2010

data QuasiQuoter Source #

The QuasiQuoter type, a value q of this type can be used in the syntax [q| ... string to parse ...|]. In fact, for convenience, a QuasiQuoter actually defines multiple quasiquoters to be used in different splice contexts. In the usual case of a QuasiQuoter that is only intended to be used in certain splice contexts, the unused fields should just fail. This is most easily accomplished using namedefaultQuasiQuoter or defaultQuasiQuoter.

This is exposed both from the template-haskell-quasiquoter and template-haskell packages. Consider importing it from the more stable template-haskell-quasiquoter if you don't need the full breadth of the template-haskell interface.

Constructors

QuasiQuoter
Fields quoteExp :: String -> Q Exp Quasi-quoter for expressions, invoked by quotes like `lhs = $[q\|...]` quotePat :: String -> Q Pat Quasi-quoter for patterns, invoked by quotes like `f $[q\|...] = rhs` quoteType :: String -> Q Type Quasi-quoter for types, invoked by quotes like `f :: $[q\|...]` quoteDec :: String -> Q [Dec] Quasi-quoter for declarations, invoked by top-level quotes

namedDefaultQuasiQuoter :: String -> QuasiQuoter Source #

A QuasiQuoter that fails with a helpful error message in every context. It is intended to be modified to create a QuasiQuoter that fails in all inappropriate contexts.

For example, you could write

myPatQQ = (namedDefaultQuasiQuoter "myPatQQ")
  { quotePat = ... }

If myPatQQ is used in an expression context, the compiler will report that, naming myPatQQ.

See also defaultQuasiQuoter, which does not name the QuasiQuoter in the error message, and might therefore be more appropriate when the users of a particular QuasiQuoter tend to define local "synonyms" for it.

defaultQuasiQuoter :: QuasiQuoter Source #

A QuasiQuoter that fails with a helpful error message in every context. It is intended to be modified to create a QuasiQuoter that fails in all inappropriate contexts.

For example, you could write

myExpressionQQ = defaultQuasiQuoter
  { quoteExp = ... }

See also namedDefaultQuasiQuoter, which names the QuasiQuoter in the error messages.

data Q a Source #

In short, Q provides the Quasi operations in one neat monad for the user.

The longer story, is that Q wraps an arbitrary Quasi-able monad. The perceptive reader notices that Quasi has only two instances, Q itself and IO, neither of which have concrete implementations.Q plays the trick of dependency inversion, providing an abstract interface for the user which is later concretely fufilled by an concrete Quasi instance, internal to GHC.

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Applicative Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods pure :: a -> Q a Source # (<>) :: Q (a -> b) -> Q a -> Q b Source # liftA2 :: (a -> b -> c) -> Q a -> Q b -> Q c Source # (>) :: Q a -> Q b -> Q b Source # (<*) :: Q a -> Q b -> Q a Source #
Functor Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods fmap :: (a -> b) -> Q a -> Q b Source # (<$) :: a -> Q b -> Q a Source #
Monad Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods (>>=) :: Q a -> (a -> Q b) -> Q b Source # (>>) :: Q a -> Q b -> Q b Source # return :: a -> Q a Source #
MonadFail Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods fail :: HasCallStack => String -> Q a Source #
MonadFix Q Source #	If the function passed to `mfix` inspects its argument, the resulting action will throw a `FixIOException`. Since: ghc-internal-2.17.0.0
Instance details Defined in GHC.Internal.TH.Monad Methods mfix :: (a -> Q a) -> Q a Source #
MonadIO Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods liftIO :: IO a -> Q a Source #
Quasi Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods qNewName :: String -> Q Name Source # qReport :: Bool -> String -> Q () Source # qRecover :: Q a -> Q a -> Q a Source # qLookupName :: Bool -> String -> Q (Maybe Name) Source # qReify :: Name -> Q Info Source # qReifyFixity :: Name -> Q (Maybe Fixity) Source # qReifyType :: Name -> Q Type Source # qReifyInstances :: Name -> [Type] -> Q [Dec] Source # qReifyRoles :: Name -> Q [Role] Source # qReifyAnnotations :: Data a => AnnLookup -> Q [a] Source # qReifyModule :: Module -> Q ModuleInfo Source # qReifyConStrictness :: Name -> Q [DecidedStrictness] Source # qLocation :: Q Loc Source # qRunIO :: IO a -> Q a Source # qGetPackageRoot :: Q FilePath Source # qAddDependentFile :: FilePath -> Q () Source # qAddDependentDirectory :: FilePath -> Q () Source # qAddTempFile :: String -> Q FilePath Source # qAddTopDecls :: [Dec] -> Q () Source # qAddForeignFilePath :: ForeignSrcLang -> String -> Q () Source # qAddModFinalizer :: Q () -> Q () Source # qAddCorePlugin :: String -> Q () Source # qGetQ :: Typeable a => Q (Maybe a) Source # qPutQ :: Typeable a => a -> Q () Source # qIsExtEnabled :: Extension -> Q Bool Source # qExtsEnabled :: Q [Extension] Source # qPutDoc :: DocLoc -> String -> Q () Source # qGetDoc :: DocLoc -> Q (Maybe String) Source #
Quote Q Source #
Instance details Defined in GHC.Internal.TH.Monad Methods newName :: String -> Q Name Source #
Monoid a => Monoid (Q a) Source #	Since: ghc-internal-2.17.0.0
Instance details Defined in GHC.Internal.TH.Monad Methods mempty :: Q a Source # mappend :: Q a -> Q a -> Q a Source # mconcat :: [Q a] -> Q a Source #
Semigroup a => Semigroup (Q a) Source #	Since: ghc-internal-2.17.0.0
Instance details Defined in GHC.Internal.TH.Monad Methods (<>) :: Q a -> Q a -> Q a Source # sconcat :: NonEmpty (Q a) -> Q a Source # stimes :: Integral b => b -> Q a -> Q a Source #

data Exp Source #

A Haskell expression.

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Eq Exp Source #

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Documentation

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