add support for flattening recursive-let

[coq-hetmet.git] / src / HaskSkolemizer.v

diff --git a/src/HaskSkolemizer.v b/src/HaskSkolemizer.v
index 6b6c756..8764102 100644 (file)
--- a/src/HaskSkolemizer.v
+++ b/src/HaskSkolemizer.v
@@ -231,12 +231,9 @@ Section HaskSkolemizer.
       | RAppCo   Γ Δ Σ κ σ₁ σ₂ γ σ lev => let case_RAppCo := tt        in _
       | RAbsCo   Γ Δ Σ κ σ  σ₁ σ₂  lev => let case_RAbsCo := tt        in _
       | RApp     Γ Δ Σ₁ Σ₂ tx te lev   => let case_RApp := tt          in _
-      | RLet     Γ Δ Σ₁ Σ₂ σ₁ σ₂ lev   => let case_RLet := tt          in _
-      | RCut    Γ Δ Σ₁ Σ₁₂ Σ₂ Σ₃ l    => let case_RCut := tt          in _
-      | RLeft   Γ Δ Σ₁ Σ₂  Σ     l    => let case_RLeft := tt in _
-      | RRight  Γ Δ Σ₁ Σ₂  Σ     l    => let case_RRight := tt in _
-      | RWhere   Γ Δ Σ₁ Σ₂ Σ₃ σ₁ σ₂ lev => let case_RWhere := tt          in _
-      | RJoin    Γ p lri m x q l       => let case_RJoin := tt in _
+      | RCut     Γ Δ Σ Σ₁ Σ₁₂ Σ₂ Σ₃ l  => let case_RCut := tt          in _
+      | RLeft    Γ Δ Σ₁ Σ₂  Σ     l    => let case_RLeft := tt in _
+      | RRight   Γ Δ Σ₁ Σ₂  Σ     l    => let case_RRight := tt in _
       | RVoid    _ _           l       => let case_RVoid := tt   in _
       | RBrak    Γ Δ t ec succ lev     => let case_RBrak := tt         in _
       | REsc     Γ Δ t ec succ lev     => let case_REsc := tt          in _
@@ -351,14 +348,6 @@ Section HaskSkolemizer.
         apply γ.
         apply (Prelude_error "found RCast at level >0").
 
-      destruct case_RJoin.
-        simpl.
-        destruct l.
-        apply nd_rule.
-        apply SFlat.
-        apply RJoin.
-        apply (Prelude_error "found RJoin at level >0").
-
       destruct case_RApp.
         simpl.
         destruct lev.
@@ -381,56 +370,8 @@ Section HaskSkolemizer.
         eapply take_unarrange.
 
         eapply nd_comp; [ idtac | eapply nd_rule; apply SFlat; eapply RArrange; apply AAssoc ].
-        eapply nd_rule; eapply SFlat; apply RWhere.
-
-      destruct case_RLet.
-        simpl.
-        destruct lev.
-        apply nd_rule.
-        apply SFlat.
-        apply RLet.
-        set (check_hof σ₁) as hof_tx.
-        destruct hof_tx; [ apply (Prelude_error "attempt to let-bind a higher-order function at depth>0") | idtac ].
-        destruct a.
-        rewrite H.
-        rewrite H0.
-
-        eapply nd_comp.
-        eapply nd_prod; [ eapply nd_rule; eapply SFlat; eapply RArrange; eapply ACanR | eapply nd_id ].
-
-        set (@RLet Γ Δ Σ₁ (Σ₂,,(take_arg_types_as_tree σ₂ @@@ (h::lev))) σ₁ (drop_arg_types_as_tree σ₂) (h::lev)) as q.
-        eapply nd_comp; [ idtac | eapply nd_rule; apply SFlat; eapply RArrange; apply AAssoc ].
-        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply q ].
-        apply nd_prod.
-          apply nd_id.
-          apply nd_rule.
-          eapply SFlat.
-          eapply RArrange.
-          eapply AuAssoc.
-
-      destruct case_RWhere.
-        simpl.
-        destruct lev.
-        apply nd_rule.
-        apply SFlat.
-        apply RWhere.
-        set (check_hof σ₁) as hof_tx.
-        destruct hof_tx; [ apply (Prelude_error "attempt to let-bind a higher-order function at depth>0") | idtac ].
-        destruct a.
-        rewrite H.
-        rewrite H0.
-
-        eapply nd_comp.
-        eapply nd_prod; [ apply nd_id | eapply nd_rule; eapply SFlat; eapply RArrange; eapply ACanR ].
-        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RArrange; eapply AAssoc ].
-        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RArrange; eapply ALeft; eapply AAssoc ].
-        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RWhere ].
-        apply nd_prod; [ idtac | eapply nd_id ].
-        eapply nd_rule; apply SFlat; eapply RArrange.
-        eapply AComp.
-        eapply AuAssoc.
-        apply ALeft.
-        eapply AuAssoc.
+        eapply nd_comp; [ apply nd_exch | idtac ].
+        eapply nd_rule; eapply SFlat; eapply RCut.
 
       destruct case_RCut.
         simpl; destruct l; [ apply nd_rule; apply SFlat; apply RCut | idtac ].
@@ -438,24 +379,38 @@ Section HaskSkolemizer.
         set (mapOptionTree drop_arg_types_as_tree Σ₃) as Σ₃'''.
         set (mapOptionTreeAndFlatten take_arg_types_as_tree Σ₁₂) as Σ₁₂''.
         set (mapOptionTree drop_arg_types_as_tree Σ₁₂) as Σ₁₂'''.
-        destruct (decide_tree_empty Σ₁₂''); [ idtac | apply (Prelude_error "used RCut on a variable with function type") ].
+        destruct (decide_tree_empty (Σ₁₂'' @@@ (h::l)));
+          [ idtac | apply (Prelude_error "used RCut on a variable with function type") ].
         destruct (eqd_dec Σ₁₂ Σ₁₂'''); [ idtac | apply (Prelude_error "used RCut on a variable with function type") ].
         rewrite <- e.
+        clear e.
+        destruct s.
         eapply nd_comp.
-        eapply nd_prod; [ apply nd_id | eapply nd_rule; eapply SFlat; eapply RArrange; eapply AuAssoc ].
+          eapply nd_prod.
+          eapply nd_rule.
+          eapply SFlat.
+          eapply RArrange.
+          eapply AComp.
+          eapply ALeft.
+          eapply arrangeCancelEmptyTree with (q:=x).
+          apply e.
+          apply ACanR.
+          apply nd_id.
         eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RArrange; eapply AAssoc ].
+        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RArrange; eapply ALeft; eapply AAssoc ].
         eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RCut ].
         apply nd_prod.
-        eapply nd_comp; [ idtac | eapply nd_rule; eapply SFlat; eapply RArrange; eapply ACanR ].
-        apply nd_rule.
-        apply SFlat.
-        apply RArrange.
-        apply ALeft.
-        destruct s.
-        eapply arrangeCancelEmptyTree with (q:=x).
-        rewrite e0.
-        admit.   (* FIXME, but not serious *)
         apply nd_id.
+        eapply nd_rule.
+          eapply SFlat.
+          eapply RArrange.
+          eapply AComp.
+          eapply AuAssoc.
+          eapply ALeft.
+          eapply AComp.
+          eapply AuAssoc.
+          eapply ALeft.
+          eapply AId.
 
       destruct case_RLeft.
         simpl; destruct l; [ apply nd_rule; apply SFlat; apply RLeft | idtac ].
@@ -537,7 +492,30 @@ Section HaskSkolemizer.
         apply nd_rule.
         apply SFlat.
         apply (@RLetRec Γ Δ lri x y nil).
-        apply (Prelude_error "RLetRec at depth>0").
+        destruct (decide_tree_empty (mapOptionTreeAndFlatten take_arg_types_as_tree y @@@ (h :: t)));
+          [ idtac | apply (Prelude_error "used LetRec on a set of bindings involving a function type") ].
+        destruct (eqd_dec y (mapOptionTree drop_arg_types_as_tree y));
+          [ idtac | apply (Prelude_error "used LetRec on a set of bindings involving a function type") ].
+        rewrite <- e.
+        clear e.
+        eapply nd_comp.
+          eapply nd_rule.
+          eapply SFlat.
+          eapply RArrange.
+          eapply ALeft.
+          eapply AComp.
+          eapply ARight.
+          destruct s.
+          apply (arrangeCancelEmptyTree _ _ e).
+          apply ACanL.
+        eapply nd_comp.
+          eapply nd_rule.
+          eapply SFlat.
+          eapply RArrange.
+          eapply AuAssoc.
+        eapply nd_rule.
+          eapply SFlat.
+          eapply RLetRec.
 
       destruct case_RCase.
         simpl.