Rewrite expressions for ocaml, lifting assignment introductions into a special let form to set the scope

1 files changed, 17 insertions, 3 deletions

diff --git a/src/rewriter.ml b/src/rewriter.ml
index ec4d01aa..8b1adfc5 100644
--- a/src/rewriter.ml
+++ b/src/rewriter.ml
@@ -117,7 +117,7 @@ let rewrite_pat rewriters nmap (P_aux (pat,(l,annot))) =
     rewrap (P_vector ps)
   | P_lit _ | P_wild | P_id _ -> rewrap pat
   | P_as(pat,id) -> rewrap (P_as( rewrite pat, id))
-  | P_typ(typ,pat) -> rewrap (P_typ(typ,rewrite pat))
+  | P_typ(typ,pat) -> rewrite pat)
   | P_app(id ,pats) -> rewrap (P_app(id, List.map rewrite pats))
   | P_record(fpats,_) ->
     rewrap (P_record(List.map (fun (FP_aux(FP_Fpat(id,pat),pannot)) -> FP_aux(FP_Fpat(id, rewrite pat), pannot)) fpats,
@@ -311,13 +311,27 @@ let rewrite_defs (Defs defs) = rewrite_defs_base
      rewrite_def = rewrite_def;
      rewrite_defs = rewrite_defs_base} (Defs defs)
 
+(*Expects to be called after rewrite_defs; thus the following should not appear:
+  internal_exp of any form
+  lit vectors in patterns or expressions
+ *)
 let rewrite_exp_lift_assign_intro rewriters nmap ((E_aux (exp,(l,annot))) as full_exp) = 
   let rewrap e = E_aux (e,(l,annot)) in
   let rewrite_rec = rewriters.rewrite_exp rewriters nmap in
   let rewrite_base = rewrite_exp rewriters nmap in
   match exp with
-  | E_block exps -> rewrap (E_block (List.map rewrite_rec exps))
-  | E_assign _ -> assert false
+  | E_block exps ->
+    let rec walker exps = match exps with
+      | [] -> []
+      | (E_aux(E_assign(le,e), (l, Base((_,t),Emp_intro,_,_,_))))::exps ->
+        let le' = rewriters.rewrite_lexp rewriters nmap le in
+        let e' = rewrite_base e in
+        let exps' = walker exps in
+        [(E_aux (E_internal_let(le', e', E_aux(E_block exps', (l, simple_annot {t=Tid "unit"}))),
+                 (l, simple_annot t)))]
+      | e::exps -> (rewrite_rec e)::(walker exps)
+    in
+    rewrap (E_block (walker exps))
   | _ -> rewrite_base full_exp
 
 let rewrite_defs_ocaml defs = rewrite_defs_base