diff options
Diffstat (limited to 'docs/examples/tcpoly/monads/Monads.scala')
-rw-r--r-- | docs/examples/tcpoly/monads/Monads.scala | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/docs/examples/tcpoly/monads/Monads.scala b/docs/examples/tcpoly/monads/Monads.scala index 5a966ce960..b6e3d5b9a8 100644 --- a/docs/examples/tcpoly/monads/Monads.scala +++ b/docs/examples/tcpoly/monads/Monads.scala @@ -6,18 +6,18 @@ trait Monads { * (>>=) :: m a -> (a -> m b) -> m b * return :: a -> m a * - * MonadTC encodes the above Haskell type class, + * MonadTC encodes the above Haskell type class, * an instance of MonadTC corresponds to a method dictionary. * (see http://lampwww.epfl.ch/~odersky/talks/wg2.8-boston06.pdf) * * Note that the identity (`this') of the method dictionary does not really correspond - * to the instance of m[x] (`self') that is `wrapped': e.g., unit does not use `self' (which + * to the instance of m[x] (`self') that is `wrapped': e.g., unit does not use `self' (which * corresponds to the argument of the implicit conversion that encodes an instance of this type class) */ // Option =:= [x] => Option[x] <: [x] => Any -// trait MonadTC[m <: [x] => Any, a] { +// trait MonadTC[m <: [x] => Any, a] { // MonadTC[m[x], a] x is a type parameter too -- should not write e.g., m[Int] here - trait MonadTC[m[x], a] { + trait MonadTC[m[x], a] { def unit[a](orig: a): m[a] // >>='s first argument comes from the implicit definition constructing this "method dictionary" @@ -32,7 +32,7 @@ trait Monads { */ trait OptionMonad extends Monads { // this implicit method encodes the Monad type class instance for Option - implicit def OptionInstOfMonad[a](self: Option[a]): MonadTC[Option, a] + implicit def OptionInstOfMonad[a](self: Option[a]): MonadTC[Option, a] = new MonadTC[Option, a] { def unit[a](orig: a) = Some(orig) def >>=[b](fun: a => Option[b]): Option[b] = self match { @@ -47,8 +47,8 @@ object main extends OptionMonad with Application { } -/* -trait MonadTC[m[x], a] requires m[x] { +/* +trait MonadTC[m[x], a] requires m[x] { def unit[a](orig: a): m[a] // >>='s first argument comes from the implicit definition constructing this "method dictionary" |