| 词条 | Hugs |
| 释义 |
|name = Hugs 98 |developer = Mark P. Jones, others |latest_release_version = September 2006 |latest_release_date = {{release_date|2006|09|21}} |status = Inactive[1] |operating_system = Cross-platform |genre = Compiler |license = BSD |website = Hugs 98 homepage }}{{Portal|Free and open-source software}} Hugs (Haskell User's Gofer System), also Hugs 98, is a bytecode interpreter for the functional programming language Haskell. Hugs is the successor to Gofer, and was originally derived from Gofer version 2.30b.[2] Hugs and Gofer were originally developed by Mark P. Jones, now a professor at Portland State University. Hugs comes with a simple graphics library. As a complete Haskell implementation that is portable and simple to install, Hugs is sometimes recommended for new Haskell users. Hugs deviates from the Haskell 98 specification[3] in several minor ways.[4] For example, Hugs does not support mutually recursive modules. A list of differences exists.[5] The Hugs prompt (a Haskell REPL) accepts expressions for evaluation, but not module, type or function definitions. Hugs can load Haskell modules at start-up.[6] ExamplesExtensible recordsAn example of "Typed records with extensibility", a non standard feature unique to Hugs.[7] 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. 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 xaddZCoord :: (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 yprintXY :: (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' Running with H98 compatibility turned off to activate language extensions:[8] runhugs -98 test.hs References1. ^{{cite web|url=https://www.haskell.org/hugs/|title=Hugs 98|website=www.haskell.org}} 2. ^{{cite web|url=http://www.haskell.org/hugs/pages/users_guide/faq.html|title=Frequently Asked Questions about Hugs|accessdate=2006-08-04}} 3. ^{{cite web|url=http://haskell.org/onlinereport/|title=Haskell 98 Language and Libraries: The Revised Report|accessdate=2006-08-03|date=December 2002|author=Simon Peyton Jones (editor)|authorlink=Simon Peyton Jones}} 4. ^{{cite web|url=http://www.haskell.org/hugs/pages/users_guide/haskell98.html#BUGS-HASKELL98|title=Haskell 98 non-compliance|work=The Hugs 98 User's Guide|accessdate=2006-08-04}} 5. ^{{cite web|url=http://www.haskell.org/hugs/pages/hugsman/diffs.html|title=List of differences with H98 standard|publisher=}} 6. ^{{cite web|url=http://www.haskell.org/hugs/pages/users_guide/module-commands.html|title=Loading and editing Haskell module files|work=The Hugs 98 User's Guide|accessdate=2006-08-04}} 7. ^{{cite web|url=http://www.haskell.org/hugs/pages/users_guide/hugs-only.html#TREX|title=Hugs-specific language extensions|website=www.haskell.org}} 8. ^{{cite web|url=http://www.haskell.org/hugs/pages/users_guide/options.html#OPTIONS-LANGUAGE|title=Changing the behaviour of Hugs|website=www.haskell.org}} External links
1 : Free Haskell implementations |
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