Added a few new features:
-o OldGrammar.pgf: if combined with -f , -c or -b , only test the specified trees+functions.
--show-context FId: shows contexts for the particular concrete category
--show-cats interacts with --debug by showing also concrete categories
* In GHC 8.4.1, the operator <> has become a method of the Semigroup class
and is exported from the Prelude. This is unfortunate, since <> is also
exported from the standard library module Text.PrettyPrint, so in any
module that defines a pretty printer, there is likely to be an ambiguity.
This affects ~18 modules in GF. Solution:
import Prelude hiding (<>)
This works also in older versions of GHC, since GHC does't complain if
you hide something that doesn't exists.
* In GHC 8.4.1, Semigroup has become a superclass of Monoid. This means
that anywhere you define an instance of the Monoid class you also have to
define an instance in the Semigroup class.
This affects Data.Binary.Builder in GF. Solution: conditionally define
a Semigroup instance if compiling with base>=4.11 (ghc>=8.4.1)
The editor doesn't show delete buttons on grammars published by other
users, but it was too picky when deciding which grammars you own. Now
it should be possible to delete grammars from the device/browser
you published it from, even if you don't have a private copy of it any more.
On a related note, there seems to be problem with the way unique grammars
names are created and maintained, causing published grammars to be duplicated
in some cases. This needs to be overhauled.
This was a problem in Safari (an other similar browsers I presume), but
not in Firefox: hovering over the grammar comment (shown below the grammar
name when you edit a grammar) didn't reveal the button to edit it, thus
preventing you from adding a comment. It was till possible by selecting the
"Enable editing on touch devices." at the bottom of the screen, but most
people probably didn't notice that it is possible to add a comment.
