fill in more gaps in the API

src/runtime/haskell/PGF.hs

@@ -7,7 +7,7 @@ module PGF ( PGF2.PGF, readPGF
            , functions, functionsByCat
 
            , PGF2.Expr(..), PGF2.Literal(..), Tree
-           , PGF2.readExpr
+           , PGF2.readExpr, PGF2.showExpr
            , PGF2.mkAbs,    PGF2.unAbs
            , PGF2.mkApp,    PGF2.unApp, PGF2.unapply
            , PGF2.mkStr,    PGF2.unStr
@@ -15,8 +15,10 @@ module PGF ( PGF2.PGF, readPGF
            , PGF2.mkDouble, PGF2.unDouble
            , PGF2.mkFloat,  PGF2.unFloat
            , PGF2.mkMeta,   PGF2.unMeta
+           , PGF2.exprSize, PGF2.exprFunctions
 
            , PGF2.Type(..), PGF2.Hypo
+           , PGF2.readType, PGF2.showType
            , PGF2.mkType, PGF2.unType
            , PGF2.mkHypo, PGF2.mkDepHypo, PGF2.mkImplHypo
 

src/runtime/haskell/PGF2.hsc

@@ -32,6 +32,8 @@ module PGF2 (-- * PGF
              mkDouble, unDouble,
              mkFloat,  unFloat,
              mkMeta,   unMeta,
+             -- extra
+             exprSize, exprFunctions,
              -- ** Types
              Type(..), Hypo, BindType(..), startCat,
              readType, showType,

src/runtime/haskell/PGF2/Expr.hs

@@ -11,6 +11,8 @@ module PGF2.Expr(Var, Cat, Fun,
                  mkFloat,  unFloat,
                  mkMeta,   unMeta,
 
+                 exprSize, exprFunctions,
+
                  mkType, unType,
                  mkHypo, mkDepHypo, mkImplHypo
 
@@ -152,6 +154,20 @@ unMeta (ETyped e ty) = unMeta e
 unMeta (EImplArg e)  = unMeta e
 unMeta _             = Nothing
 
+exprSize :: Expr -> Int
+exprSize (EAbs _ _ e) = exprSize e
+exprSize (EApp e1 e2) = exprSize e1 + exprSize e2
+exprSize (ETyped e ty)= exprSize e
+exprSize (EImplArg e) = exprSize e
+exprSize _            = 1
+
+exprFunctions :: Expr -> [Fun]
+exprFunctions (EAbs _ _ e) = exprFunctions e
+exprFunctions (EApp e1 e2) = exprFunctions e1 ++ exprFunctions e2
+exprFunctions (ETyped e ty)= exprFunctions e
+exprFunctions (EImplArg e) = exprFunctions e
+exprFunctions (EFun f)     = [f]
+exprFunctions _            = []
 
 -- | creates a type from list of hypothesises, category and 
 -- list of arguments for the category. The operation