Add reUnknownExtension

Cabal-described/src/Distribution/Described/Extension.hs

@@ -3,6 +3,7 @@
 module Distribution.Described.Extension
   ( reEnableExtension
   , reKnownExtension
+  , reUnknownExtension
   , reDisableExtension
   , reXs
       -- * Extension groups
@@ -38,15 +39,22 @@ import Language.Haskell.Extension
 
 instance Described Extension where
     describe _ = REUnion
-        [ RENamed "enable-extension" reKnownExtension
-        , RENamed "disable-extension" reDisableExtension
+        [ reEnableExtension
+        , reDisableExtension
+        , reUnknownExtension
         ]
 
 reXs :: [KnownExtension] -> GrammarRegex a
 reXs xs = REUnion (fromString . prettyShow <$> xs)
 
 reEnableExtension :: GrammarRegex a
-reEnableExtension = "enable-extension"
+reEnableExtension = RENamed "enable-known-extension" reKnownExtension
+
+reDisableExtension :: GrammarRegex a
+reDisableExtension = REUnion ["No" <> reEnableExtension]
+
+reUnknownExtension :: GrammarRegex a
+reUnknownExtension = RENamed "unknown-extension" RETodo
 
 reKnownExtension :: GrammarRegex a
 reKnownExtension = REUnion
@@ -74,9 +82,6 @@ reKnownExtension = REUnion
     , RENamed "ungrouped-extension" $ reXs xUngrouped
     ]
 
-reDisableExtension :: GrammarRegex a
-reDisableExtension = REUnion ["No" <> RENamed "enable-extension" reKnownExtension]
-
 -- The comments in the xGroup* lists are taken from the GHC User's Guide. Stop
 -- the formatter from rearranging them with:
 {- FOURMOLU_DISABLE -}

Cabal-syntax-docs/ghc/Main.hs

@@ -24,10 +24,12 @@ main = do
             contents <- run $ Z
                 { zGhcBuildInfoFields = biGhc
                 , zProductions =
-                    [ zproduction "disable-extension" reDisableExtension
+                    [ zproduction "disable-known-extension" reDisableExtension
                         "Disable a language extension by prepending the extension with \"No\"."
-                    , zproduction "enable-extension" reKnownExtension
-                        "All GHC language extensions known to cabal. There may be more and some of these may be on by default."
+                    , zproduction "enable-known-extension" reKnownExtension
+                        "All \"known\" language extensions. There may be more and some of these may be on by default."
+                    , zproduction "unknown-extension" reUnknownExtension
+                        "Any token for any unknown extension is acceptable."
                     , zproduction "interactive-extension" (reXs xGroupInteractive)
                         "Language Extensions related to GHC interactive."
                     , zproduction "phase-extension" (reXs xGroupPhase)

doc/ghc-syntax.rst

@@ -17,7 +17,7 @@ default-extensions
 
     .. math::
 
-        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}extension}}\mid\mathop{\mathit{disable\text{-}extension}} \right\}
+        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathord{``}\mathtt{No}\mathord{"}}\mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathit{unknown\text{-}extension}} \right\}
 
 .. _ghc-default-language:
 
@@ -39,7 +39,7 @@ extensions
 
     .. math::
 
-        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}extension}}\mid\mathop{\mathit{disable\text{-}extension}} \right\}
+        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathord{``}\mathtt{No}\mathord{"}}\mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathit{unknown\text{-}extension}} \right\}
 
 .. _ghc-other-extensions:
 
@@ -49,7 +49,7 @@ other-extensions
 
     .. math::
 
-        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}extension}}\mid\mathop{\mathit{disable\text{-}extension}} \right\}
+        \mathrm{optcommalist}\left\{ \mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathord{``}\mathtt{No}\mathord{"}}\mathop{\mathit{enable\text{-}known\text{-}extension}}\mid\mathop{\mathit{unknown\text{-}extension}} \right\}
 
 .. _ghc-other-languages:
 
@@ -77,24 +77,33 @@ users' guide on language extensions.
     of the ``.cabal`` file specification and shown here only as a convenience.
     The GHC users' guide is the place to look these up.
 
-.. _ghc-disable-extension:
+.. _ghc-disable-known-extension:
 
-disable-extension
+disable-known-extension
     Disable a language extension by prepending the extension with "No".
 
     .. math::
 
-        \mathop{\mathord{``}\mathtt{No}\mathord{"}}\mathop{\mathit{enable\text{-}extension}}
+        \mathop{\mathord{``}\mathtt{No}\mathord{"}}\mathop{\mathit{enable\text{-}known\text{-}extension}}
 
-.. _ghc-enable-extension:
+.. _ghc-enable-known-extension:
 
-enable-extension
-    All GHC language extensions known to cabal. There may be more and some of these may be on by default.
+enable-known-extension
+    All "known" language extensions. There may be more and some of these may be on by default.
 
     .. math::
 
         \left\{ \begin{gathered}\mathop{\mathit{interactive\text{-}extension}}\\\mathop{\mathit{phase\text{-}extension}}\\\mathop{\mathit{syntax\text{-}extension}}\\\mathop{\mathit{import\text{-}export\text{-}extension}}\\\mathop{\mathit{type\text{-}extension}}\\\mathop{\mathit{record\text{-}extension}}\\\mathop{\mathit{deriving\text{-}extension}}\\\mathop{\mathit{pattern\text{-}extension}}\\\mathop{\mathit{classes\text{-}instances\text{-}extension}}\\\mathop{\mathit{literals\text{-}extension}}\\\mathop{\mathit{constraint\text{-}extension}}\\\mathop{\mathit{type\text{-}signature\text{-}extension}}\\\mathop{\mathit{binding\text{-}generalisation\text{-}extension}}\\\mathop{\mathit{template\text{-}haskell\text{-}extension}}\\\mathop{\mathit{bang\text{-}strict\text{-}extension}}\\\mathop{\mathit{parallel\text{-}concurrent\text{-}extension}}\\\mathop{\mathit{unboxed\text{-}primitive\text{-}extension}}\\\mathop{\mathit{foreign\text{-}extension}}\\\mathop{\mathit{safe\text{-}extension}}\\\mathop{\mathit{miscellaneous\text{-}extension}}\\\mathop{\mathit{bugs\text{-}extension}}\\\mathop{\mathit{ungrouped\text{-}extension}}\end{gathered} \right\}
 
+.. _ghc-unknown-extension:
+
+unknown-extension
+    Any token for any unknown extension is acceptable.
+
+    .. math::
+
+        \mathsf{\color{red}{TODO}}
+
 .. _ghc-interactive-extension:
 
 interactive-extension