[Hackage] #567: Allow negation of language extension names by adding/removing "No" in front

[Hackage]

#567: Allow negation of language extension names by adding/removing "No" in front
----------------------------+-----------------------------------------------
  Reporter:  SamB           |        Owner:         
      Type:  enhancement    |       Status:  new    
  Priority:  normal         |    Milestone:         
 Component:  Cabal library  |      Version:  1.6.0.1
  Severity:  normal         |   Resolution:         
  Keywords:                 |   Difficulty:  unknown
Ghcversion:                 |     Platform:         
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Comment (by duncan):

 Specifically how about:

 {{{
 data Extension =
   ...
   {- all the existing extensions -}
   ...
   Negated Extension
 }}}

 and add a function:
 {{{
 negateExtension :: Extension -> Extension
 negateExtension (Negated e) = e
 negateExtension          e  = Negated e
 }}}
 and extend the parser and pretty printer. Specifically, all extensions are
 to be negated syntactically by adding a 'No' prefix, or if it already
 begins with 'No' then removing the prefix.

 This is also related to the proposal to remove the 'NoMonoPatBinds'
 extension and add an extension 'MonoPatBinds'. It's not immediately clear
 if it affects it positively or negatively.

-- 
Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/567#comment:1>
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