guard

guard :: MonadPlus m => Bool -> m ()
base Control.Monad
guard b is return () if b is True, and mzero if b is False.
data Guard
template-haskell Language.Haskell.TH.Syntax, template-haskell Language.Haskell.TH
package guarded-rewriting
package
This package provides rewriting functionality for datatypes. Most forms of datatypes are supported, including parametrized and mutually-recursive. This library has been described in the paper: * Thomas van Noort, Alexey Rodriguez Yakushev, Stefan Holdermans, Johan Jeuring, Bastiaan Heeren, Jose Pedro Magalhaes. A Lightweight Approach to Datatype-Generic Rewriting. Journal of Functional Programming, Special Issue on Generic Programming, 2010. More information about this library can be found at http://www.cs.uu.nl/wiki/GenericProgramming/GuardedRewriting. Version 0.1
GuardedB :: [(Guard, Exp)] -> Body
template-haskell Language.Haskell.TH.Syntax, template-haskell Language.Haskell.TH
> f p { | e1 = e2 | e3 = e4 }
guardedB :: [Q (Guard, Exp)] -> BodyQ
template-haskell Language.Haskell.TH.Lib, template-haskell Language.Haskell.TH
type GuardQ = Q Guard
template-haskell Language.Haskell.TH.Lib, template-haskell Language.Haskell.TH
nonExhaustiveGuardsError :: Addr# -> a
base Control.Exception.Base
HsGuardedAlt :: SrcLoc -> HsExp -> HsExp -> HsGuardedAlt
haskell-src Language.Haskell.Syntax
data HsGuardedAlt
haskell-src Language.Haskell.Syntax
A guarded alternative | exp -> exp. The first expression will be Boolean-valued.
HsGuardedAlts :: [HsGuardedAlt] -> HsGuardedAlts
haskell-src Language.Haskell.Syntax
gdpat
data HsGuardedAlts
haskell-src Language.Haskell.Syntax
HsGuardedRhs :: SrcLoc -> HsExp -> HsExp -> HsGuardedRhs
haskell-src Language.Haskell.Syntax
data HsGuardedRhs
haskell-src Language.Haskell.Syntax
A guarded right hand side | exp = exp. The first expression will be Boolean-valued.
HsGuardedRhss :: [HsGuardedRhs] -> HsRhs
haskell-src Language.Haskell.Syntax
guarded right hand side (gdrhs)
HsUnGuardedAlt :: HsExp -> HsGuardedAlts
haskell-src Language.Haskell.Syntax
-> exp
HsUnGuardedRhs :: HsExp -> HsRhs
haskell-src Language.Haskell.Syntax
unguarded right hand side (exp)