Remove hardcoded default GC from command line options

src/Core/Options.idr

@@ -49,6 +49,12 @@ Eq CG where
   Gambit == Gambit = True
   _ == _ = False
 
+export
+Show CG where
+  show Chez = "chez"
+  show Racket = "racket"
+  show Gambit = "gambit"
+
 export
 availableCGs : List (String, CG)
 availableCGs
@@ -138,13 +144,14 @@ record Options where
   extensions : List LangExt
 
 defaultDirs : Dirs
-defaultDirs = MkDirs "." Nothing "build" 
-                     ("build" </> "exec") 
+defaultDirs = MkDirs "." Nothing "build"
+                     ("build" </> "exec")
                      "/usr/local" ["."] [] []
 
 defaultPPrint : PPrinter
 defaultPPrint = MkPPOpts False True False
 
+export
 defaultSession : Session
 defaultSession = MkSessionOpts False False False Chez 0 False False
                                Nothing Nothing Nothing Nothing

src/Core/TTC.idr

@@ -731,14 +731,14 @@ TTC CDef where
 export
 TTC CG where
   toBuf b Chez = tag 0
-  toBuf b Racket = tag 2
-  toBuf b Gambit = tag 3
+  toBuf b Racket = tag 1
+  toBuf b Gambit = tag 2
 
   fromBuf b
       = case !getTag of
              0 => pure Chez
-             2 => pure Racket
-             3 => pure Gambit
+             1 => pure Racket
+             2 => pure Gambit
              _ => corrupt "CG"
 
 export

src/Idris/CommandLine.idr

@@ -4,6 +4,8 @@ import IdrisPaths
 
 import Idris.Version
 
+import Core.Options
+
 import Data.List
 import Data.Maybe
 import Data.Strings
@@ -44,7 +46,7 @@ data CLOpt
   OutputFile String |
    ||| Execute a given function after checking the source file
   ExecFn String |
-   ||| Use a specific code generator (default chez)
+   ||| Use a specific code generator
   SetCG String |
    ||| Don't implicitly import Prelude
   NoPrelude |
@@ -113,7 +115,7 @@ options = [MkOpt ["--check", "-c"] [] [CheckOnly]
            MkOpt ["--no-prelude"] [] [NoPrelude]
               (Just "Don't implicitly import Prelude"),
            MkOpt ["--codegen", "--cg"] ["backend"] (\f => [SetCG f])
-              (Just "Set code generator (default chez)"),
+              (Just $ "Set code generator (default \""++ show (codegen defaultSession) ++ "\")"),
            MkOpt ["--package", "-p"] ["package"] (\f => [PkgPath f])
               (Just "Add a package as a dependency"),