Hi, Am Sonntag, den 29.10.2017, 16:40 -0400 schrieb David Feuer:
1. To be able to display cyclical data in some sensible way.
x = "hi" : x x `seq` () :print x
should print some useful representation of x.
the best that I know for this is the hack that calls itself ghc-heap- view: ~ $ cabal install ghc-heap-view ~ $ ghci GHCi, version 8.0.2: http://www.haskell.org/ghc/ :? for help Prelude> :script .cabal/share/x86_64-linux-ghc-8.0.2/ghc-heap-view-0.5.10/ghci Prelude> x = "hi" : x Prelude> take 2 x ["hi","hi"] Prelude> :printHeap x let x1 = _bh (C# 'h' : _bh (C# 'i' : _bh [])) : _bh x1 in x1 Prelude> System.Mem.performGC Prelude> :printHeap x let x1 = "hi" : x1 in x1 A graphical front-end is ghc-vis: http://felsin9.de/nnis/ghc-vis/ But it is mostly a hack and you should not expect a lot of reliability of it. I’d love to see it supported by GHC proper. Erik de Castro Lopo tried to merge it into GHC, but it seems to be very hard.
2. To be able to force cyclical data without looping.
x = "hi" : x :force x
That could be implemented on top of ghc-heap-view. Greetings, Joachim -- Joachim Breitner mail@joachim-breitner.de http://www.joachim-breitner.de/