#12508: Show evaluation step-by-step in GHCi -------------------------------------+------------------------------------- Reporter: Hi-Angel | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: GHCi | Version: 8.0.1 Keywords: interactive | Operating System: Unknown/Multiple evaluation debugging | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The ability see every evaluation step for executing a particular code in ghci is needed. Earlier that could have [[http://stackoverflow.com/a/554391/2388257|done in HAT]], or ghc-vis. But as of today, HAT doesn't compile even with stack. And, at least personally for me, neither ghc-vis could be installed. I want to point out that the funcionality is **very** important for the language. Without that ''(i.e. as it is now)'' it is impossible for newcomers to see how a particular construction going to be evaluated, how much memory it going to take. Nowadays newcomers have to deal with memory issues post-mortem: an app takes all system memory, dies, then one build everything for profiling, and start playing a Battleship with the allocation graph; which going to be a hard game, unless you're experienced enough to not even allow that to happen most of the times. However, if there was a way to execute functions in GHCI, looking the evaluation step-by-step, days of hard debugging would turn into a few hours of executing a couple of functions in ghci. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12508 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler