* Use implicit Prelude
The previous behavior was introduced as a fix for #4464. It seems that
this change alone did not fix the issue, and `stack ghci` and `cabal
repl` only work with GHC 8.4.1 or newer, as no custom Prelude is loaded
for these versions. Given this, it seems cleaner to revert to the
implicit Prelude.
* PandocMonad: remove outdated check for base version
Only base versions 4.9 and later are supported, the check for
`MIN_VERSION_base(4,8,0)` is therefore unnecessary.
* Always use custom prelude
Previously, the custom prelude was used only with older GHC versions, as
a workaround for problems with ghci. The ghci problems are resolved by
replacing package `base` with `base-noprelude`, allowing for consistent
use of the custom prelude across all GHC versions.
Don't use custom prelude for latest ghc.
This is a better approach to making 'stack ghci' and 'cabal repl'
work. Instead of using NoImplicitPrelude, we only use the custom
prelude for older ghc versions. The custom prelude presents a
uniform API that matches the current base version's prelude.
So, when developing (presumably with latest ghc), we don't
use a custom prelude at all and hence have no trouble with ghci.
The custom prelude no longer exports (<>): we now want to
match the base 4.8 prelude behavior.
- The (non-exported) prelude is in prelude/Prelude.hs.
- It exports Monoid and Applicative, like base 4.8 prelude,
but works with older base versions.
- It exports (<>) for mappend.
- It hides 'catch' on older base versions.
This allows us to remove many imports of Data.Monoid
and Control.Applicative, and remove Text.Pandoc.Compat.Monoid.
It should allow us to use -Wall again for ghc 7.10.
