#8403: Pretty-printing of long types -------------------------------------+------------------------------------- Reporter: monoidal | Owner: Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: Type of failure: Other | Unknown/Multiple Blocked By: | Test Case: Related Tickets: #9428 | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by phadej): With the test program: {{{ import Text.PrettyPrint -- mocking how compiler/types/TypeRep.hs would print the type pairUntil :: Char -> Doc pairUntil c = pprArrowChain (varDocs ++ [resultPair]) where varDocs = map char ['a'..c] resultPair = parens (sep (punctuate comma varDocs)) arrow :: Doc arrow = text "->" pprArrowChain :: [Doc] -> Doc -- pprArrowChain [a,b,c] generates a -> b -> c pprArrowChain [] = empty pprArrowChain (arg:args) = sep [arg, sep (map (arrow <+>) args)] }}} {{{ λ> Test.pairUntil 'd' a -> b -> c -> d -> (a, b, c, d) λ> Test.pairUntil 'k' a -> b -> c -> d -> e -> f -> g -> h -> i -> j -> k -> (a, b, c, d, e, f, g, h, i, j, k) }}} I have no good ideas how to define "more packed", yet so output is still understandable. E.g. will this "less area" method work for all types: {{{ a -> b -> c -> d -> e -> f -> g -> h -> i -> j -> k -> l -> m -> n -> o -> p -> q -> r -> s -> t -> u -> v -> w -> x -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x) }}} My gut feelings that the layout algorithm won't be linear anymore, don't know if that is the problem though. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8403#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler