pgf-shell: show the names of the concrete syntaxes after loading the grammar

src/runtime/haskell-bind/examples/pgf-shell.hs

@@ -9,6 +9,7 @@
 
 import Control.Monad(forever)
 import Data.Char(isSpace)
+import qualified Data.Map as M
 import System.IO(hFlush,stdout)
 import System.IO.Error(catchIOError)
 import System.Environment
@@ -22,9 +23,10 @@ getPGF [path] = pgfShell =<< readPGF path
 getPGF _ = putStrLn "Usage: pgf-shell <path to pgf>"
 
 pgfShell pgf =
-  forever $ do performGC
-               putStr "> "; hFlush stdout
-               execute pgf =<< readLn
+  do putStrLn . unwords . map (show.fst) . M.toList $ languages pgf
+     forever $ do performGC
+                  putStr "> "; hFlush stdout
+                  execute pgf =<< readLn
 
 execute pgf cmd =
   case cmd of

src/runtime/haskell-bind/haskell-bind.cabal

@@ -19,7 +19,8 @@ cabal-version:       >=1.10
 library
   exposed-modules:     CId, CRuntimeFFI
   other-modules:       Gu, PgfLow
-  build-depends:       base >=4.5 && <4.7, bytestring >=0.9 && <0.11, pretty >=1.1 && <1.2
+  build-depends:       base >=4.5 && <4.7, bytestring >=0.9 && <0.11,
+                       pretty >=1.1 && <1.2, containers
   -- hs-source-dirs:      
   build-tools:         hsc2hs
   extra-libraries:     gu pgf
@@ -29,7 +30,7 @@ library
 executable pgf-shell
   main-is:             pgf-shell.hs
   hs-source-dirs:      examples
-  build-depends:       base, haskell-bind
+  build-depends:       base, haskell-bind, containers
   default-language:    Haskell2010
   if impl(ghc>=7.0)
     ghc-options: -rtsopts