'-interactive-print myPrint' forgotten after :load or :reload

Hi,

I would like to use a custom print function. I tried all possible ways for setting it: (1) running ghci -interactive-print myPrint; (2) adding ':set -interactive-print myPrint' to ~/.ghci; (3) typing ':set -interactive-print myPrint' interactively. It works, but only before :load or :reload. After that,it's forgotten (standard print used again) and I have to type ':set -interactive-print myPrint' again. Is there a way to make this setting persistent, i. e. survive after :load or :reload?

Thanks.

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

I forgot to mention my version of ghc: 7.6.3.

Trac metadata

Trac field	Value
Version	7.10.2 → 7.6.3

Still a problem with HEAD.

Maybe the creator of this feature, @bravit, knows a solution?

Trac metadata

Trac field	Value
Related	- → #5461 (closed)

Trac metadata

Trac field	Value
Component	Compiler → GHCi

This was fixed already in https://phabricator.haskell.org/D867

It works as expected in HEAD, but not in 7.10.3.

Hi bravit, thanks for having a look.

After a :reload, the interactive printer doesn't work anymore. Here is an example.

$ cat Test.hs
module SpecPrinter where
import System.IO

sprint a = putStrLn $ show a ++ "!"

$ ~/ghc-devel2/inplace/bin/ghc-stage2 --version
The Glorious Glasgow Haskell Compilation System, version 7.11.20151216

$ ~/ghc-devel2/inplace/bin/ghc-stage2 --interactive -interactive-print=SpecPrinter.sprint Test
GHCi, version 7.11.20151216: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling SpecPrinter      ( Test.hs, interpreted )
Ok, modules loaded: SpecPrinter.
*SpecPrinter> "hi"
"hi"!
*SpecPrinter> :reload
Ok, modules loaded: SpecPrinter.
*SpecPrinter> "hi"
"hi"

Note that after the :reload, the exclamation mark (!) isn't printed anymore.

Do you agree this is not working as expected? I'm seeing the same behaviour with ghc-7.10.3 as with HEAD.

CC @watashi, as the author of D867. I also note that a test was missing from that Diff, so maybe it recently got broken again?

Hi thomie,

If interactive printing function is defined in external package then it is kept after reloading (thanks to D867, now in HEAD). If it is defined locally then it is no more effective after reloading, it's a new function in some way. I consider this behaviour as reasonable. Don't you agree?

mentioned in commit 7cddcde5

closed

changed milestone to %8.0.1

Ah, ok, I missed the "external package" part. Sounds reasonable.

I updated the User's Guide to mention this.

Thanks!

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed
Component	GHCi → Documentation

added documentation label

added Pnormal label