From adbe9cd94d6e9fef2811c52863c70649b6145f14 Mon Sep 17 00:00:00 2001
From: krasimir <krasimir@chalmers.se>
Date: Sat, 8 Jan 2011 20:55:58 +0000
Subject: [PATCH] fix the computation of abstract expressions in the presence
 of implicit arguments

---
 src/runtime/haskell/PGF/Expr.hs                         | 8 ++++++--
 testsuite/runtime/typecheck/implicit-arguments.gfs      | 1 +
 testsuite/runtime/typecheck/implicit-arguments.gfs.gold | 2 ++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/runtime/haskell/PGF/Expr.hs b/src/runtime/haskell/PGF/Expr.hs
index 71e35be5e..db6e7cfd3 100644
--- a/src/runtime/haskell/PGF/Expr.hs
+++ b/src/runtime/haskell/PGF/Expr.hs
@@ -354,7 +354,9 @@ apply sig env (EFun f)     vs     = case Map.lookup f (fst sig) of
                                                              Nothing  -> VApp f vs
                                       Nothing           -> error ("unknown function "++showCId f)
 apply sig env (EApp e1 e2) vs     = apply sig env e1 (eval sig env e2 : vs)
-apply sig env (EAbs _ x e) (v:vs) = apply sig (v:env) e vs
+apply sig env (EAbs b x e) (v:vs) = case (b,v) of
+                                      (Implicit,VImplArg v) -> apply sig (v:env) e vs
+                                      (Explicit,         v) -> apply sig (v:env) e vs
 apply sig env (EMeta i)    vs     = case snd sig i of
                                       Just e  -> apply sig env e vs
                                       Nothing -> VMeta i env vs
@@ -369,7 +371,9 @@ applyValue sig (VMeta i env vs0)         vs       = VMeta i env (vs0++vs)
 applyValue sig (VGen  i vs0)             vs       = VGen  i (vs0++vs)
 applyValue sig (VSusp i env vs0 k)       vs       = VSusp i env vs0 (\v -> applyValue sig (k v) vs)
 applyValue sig (VConst f vs0)            vs       = VConst f (vs0++vs)
-applyValue sig (VClosure env (EAbs b x e)) (v:vs) = apply sig (v:env) e vs
+applyValue sig (VClosure env (EAbs b x e)) (v:vs) = case (b,v) of
+                                                      (Implicit,VImplArg v) -> apply sig (v:env) e vs
+                                                      (Explicit,         v) -> apply sig (v:env) e vs
 applyValue sig (VImplArg _)              vs       = error "implicit argument in function position"
 
 -----------------------------------------------------
diff --git a/testsuite/runtime/typecheck/implicit-arguments.gfs b/testsuite/runtime/typecheck/implicit-arguments.gfs
index 5667a2647..49850aeef 100644
--- a/testsuite/runtime/typecheck/implicit-arguments.gfs
+++ b/testsuite/runtime/typecheck/implicit-arguments.gfs
@@ -8,3 +8,4 @@ ai <\x -> x : ({m},n : Node) -> Node>
 ai <n1 : ({m} : Node) -> Node>
 ai <? : ({m} : Node) -> Node>
 ai <link id : Path n1 n1>
+pt -compute <\{n} -> n : ({n} : Node) -> Node> {n1}
diff --git a/testsuite/runtime/typecheck/implicit-arguments.gfs.gold b/testsuite/runtime/typecheck/implicit-arguments.gfs.gold
index e0a83f5b6..3292c2ea1 100644
--- a/testsuite/runtime/typecheck/implicit-arguments.gfs.gold
+++ b/testsuite/runtime/typecheck/implicit-arguments.gfs.gold
@@ -31,3 +31,5 @@ Expression:  <link {n1} {n1} (id {n1}) : Path n1 n1>
 Type:        Path n1 n1
 Probability: 1.0
 
+n1
+