#10067: The Read Integer instance is too slow -------------------------------------+------------------------------------- Reporter: redneb | Owner: Type: feature | Status: new request | Milestone: Priority: low | Version: 7.11 Component: | Operating System: Unknown/Multiple libraries/base | Type of failure: Runtime Keywords: | performance bug Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The current implementation of the Read Integer instance has quadratic complexity and thus performs badly on large inputs. On my system, it takes 65 seconds to perform the following: {{{#!hs read (take 1000000 $ cycle "1234567890") :: Integer }}} Note that we already provide an ad-hoc instance for Show Integer, so maybe we can do the same for Read Integer. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10067 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler