- #Hugs 98 iomonad how to#
- #Hugs 98 iomonad install#
- #Hugs 98 iomonad portable#
- #Hugs 98 iomonad license#
More flexible instance declarations 6.2.3. Although not part of the official Haskell 98 language, multi-parameter. Language extensions supported by Hugs and GHC 6.1. the error message reported (by HUGS) was of an invalid type constructor in the. Compiling modules that use the Foreign Function Interface 4.3. Adding packages to a Hugs installation 4. Loading and editing Haskell module files 2.3.
#Hugs 98 iomonad license#
Running with H98 compatibility turned off to activate language extensions: runhugs -98 test.Table of Contents The Hugs 98 License 1. extension - (x=v | rec) - record value decomposition, pattern fields must be non empty - (x::type | rec) - record type decomposition - (rec\z) in the context means ''rec'' does not contain field ''z'' - add a field z with the same type as field x addZCoord :: ( r \ z, r \ x ) => t -> Rec ( x :: t | r ) -> Rec ( x :: t, z :: t | r ) addZCoord z ( x = x | other ) = ( x = x, z = z | other ) point3D = addZCoord 3 point2D - :: Point3D - admit any record with ''showable'' fields x and y printXY :: ( Show t, r \ x, r \ y ) => Rec ( x :: t, y :: t | r ) -> IO () printXY point = putStrLn xy - with SML style field accessors ('#' prefix) where xy = show ( # x point ) ++ ", " ++ show ( # y point ) incrementX :: ( Num t, r \ x ) => Rec ( x :: t | r ) -> Rec ( x :: t | r ) incrementX ( x = v | rest ) = ( x = v + 1 | rest ) main = do let point3D' = incrementX point3D printXY point2D printXY point3D' The official (revised) Haskell98 report defining the syntax and an informal abstract. Module Main where import Hugs.Trex type Coord = Double type Point2D = Rec ( x :: Coord, y :: Coord ) type Point3D = Rec ( x :: Coord, y :: Coord, z :: Coord ) point2D = ( x = 1, y = 1 ) :: Point2D - emptyRec :: Rec EmptyRow - predefined - (x=1 | (y=1)) - rec. Official Website Explanation of common Hugs error messages. Some Haskell systems (HUGS, 2005 GHC, 2005) that allow functional dependen.
#Hugs 98 iomonad how to#
All the other documentation I could find was regarding installing the full Haskell platform and GHC, so if all you want is Hugs 98 for a university module, here’s how to get it. IO monad, and hence, by the functional dependency, that r must be an IORef. Jeff Lewis helped me understand the internals of Hugs.
#Hugs 98 iomonad install#
Examples Extensible records Īn example of "Typed records with extensibility", a non standard feature unique to Hugs. Here’s the latest instructions for how to install Hugs 98 on macOS. Andy Moran collaborated with us in developing the semantics of value recursion for the IO monad. Hugs can load Haskell modules at start-up. The Hugs prompt (a Haskell REPL) accepts expressions for evaluation, but not module, type or function definitions. For example, Hugs does not support mutually recursive modules. ross 2 04:24:03 PST Modified files: src iomonad.c storage.h Log: More preparation for byte encoding of Chars in I/O: if CHARENCODING is defined (which it isn't yet), we need to know if a Handle was opened in binary mode (to turn off the encoding), and Chars pushed back must be stored in the Handle, rather than fed to ungetc(). Hugs deviates from the Haskell 98 specification in several minor ways.
#Hugs 98 iomonad portable#
As a complete Haskell implementation that is portable and simple to install, Hugs is sometimes recommended for new Haskell users. Hugs comes with a simple graphics library. Jones, now a professor at Portland State University. Haskells IO monad provides a way of tackling the awkward squad: I/O.
Hugs and Gofer were originally developed by Mark P. Haskell 1.0Haskell 98Haskell A History of Haskell: Being Lazy with Class. Hugs is the successor to Gofer, and was originally derived from Gofer version 2.30b. Hugs ( Haskell User's Gofer System), also Hugs 98, is a bytecode interpreter for the functional programming language Haskell.
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