Changeset 5170

Timestamp:

07/04/05 00:37:10 (3 years ago)

Author:

autrijus

svk:copy_cache_prev:

6965

Message:

* eval now pushes one caller frame, just as Perl5's eval does.

Location:

src/Pugs

Files:

• Monads.hs (modified) (2 diffs)
• Prim/Eval.hs (modified) (2 diffs)

src/Pugs/Monads.hs

@@ -48 +48 @@
 enterEvalContext :: Cxt -> Exp -> Eval Val
 enterEvalContext cxt = enterContext cxt . evalExp
+
+{-|
+Perform the specified evaluation in the specified package.
+
+(Subsequent chained 'Eval's do /not/ see this package.)
+-}
+enterPackage :: String -> Eval a -> Eval a
+enterPackage pkg = local (\e -> e{ envPackage = pkg })
+
+{-|
+Enter a new environment and mark the previous one as 'Caller'.
+-}
+enterCaller :: Eval a -> Eval a
+enterCaller = local (\env -> env
+    { envCaller = Just env
+    , envDepth = envDepth env + 1 })
 
 {-|
@@ -240 +256 @@
         } ]
 
--- | (This doesn't seem to be used at the moment...)
-caller :: Int -> Eval Env
-caller n = do
-    depth <- asks envDepth
-    when (depth <= n) $
-        fail "Cannot ask for deeper depth"
-    asks $ foldl (.) id $ replicate n (fromJust . envCaller)
-
 evalVal :: Val -> Eval Val
 evalVal val = do

src/Pugs/Prim/Eval.hs

@@ -11 +11 @@
 import Pugs.Parser.Program
 import Pugs.Embed
+import Pugs.Monads
 import Pugs.Internals
 import Pugs.Pretty
@@ -85 +86 @@
             EvalResultEnv -> (`mergeStmts` Syn "env" [])
             _             -> id
-    val <- resetT $ local (const env') $ do
+    val <- resetT $ local (const env') $ enterCaller $ do
         evl <- asks envEval
         evl (trans $ envBody env')