Retain export-list order in ModIface, use it in :browse

while trying to write a test for an extension of :browse, i encountered an issue with the existing functionality: the order of names is not stable, making it difficult to write meaningful tests for :browse.

a reduced test case & output are appended below, showing that output order is affected by prior usage, in both 6.6.1 and HEAD.

i would prefer for the items to appear in source order, but at the point :browse gets a hand on them, source location information might not be available; sorting by Name would be random due to uniqueIds, and lexicographic sorting would be confusing to users (spreading related items all over the alphabet, instead of keeping the order in which they appear in source and documentation).

is there a way to keep the items in source order, within each module (modules themselves could be sorted lexicographically)? note that alphabetically sorting names would very much be a last resort!

--------------------------------------- testing :browse
$ cat y.hs
import Prelude()
import Data.Maybe(catMaybes,mapMaybe)

$ cat .ghci
:t Data.Maybe.mapMaybe

$ ghcii.sh --version
The Glorious Glasgow Haskell Compilation System, version 6.6.1

$ /cygdrive/c/fptools/ghc/compiler/stage2/ghc-inplace --interactive --version
The Glorious Glasgow Haskell Compilation System, version 6.9.20071019

$ (echo :l y.hs;echo :browse '*Main') | ghcii.sh -v0
Data.Maybe.mapMaybe :: (a -> Maybe b) -> [a] -> [b]
mapMaybe :: (a -> Data.Maybe.Maybe b) -> [a] -> [b]
catMaybes :: [Data.Maybe.Maybe a] -> [a]

$ (echo :l y.hs;echo :browse '*Main') | ghcii.sh -v0 -ignore-dot-ghci
catMaybes :: [Data.Maybe.Maybe a] -> [a]
mapMaybe :: (a -> Data.Maybe.Maybe b) -> [a] -> [b]

$ (echo :l y.hs;echo :browse '*Main') | /cygdrive/c/fptools/ghc/compiler/stage2/ghc-inplace --inter
active  -v0
Data.Maybe.mapMaybe :: (a -> Maybe b) -> [a] -> [b]
mapMaybe :: (a -> Data.Maybe.Maybe b) -> [a] -> [b]
catMaybes :: [Data.Maybe.Maybe a] -> [a]

$ (echo :l y.hs;echo :browse '*Main') | /cygdrive/c/fptools/ghc/compiler/stage2/ghc-inplace --inter
active  -v0 -ignore-dot-ghci
catMaybes :: [Data.Maybe.Maybe a] -> [a]
mapMaybe :: (a -> Data.Maybe.Maybe b) -> [a] -> [b]

Trac metadata

Trac field	Value
Version	6.6.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	GHCi
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	claus.reinke@talk21.com
Operating system	Unknown
Architecture	Unknown