Explify cfold

5 files changed, 10 insertions, 1 deletions

diff --git a/src/corify.sml b/src/corify.sml
index 4046a02a..b4a7108e 100644
--- a/src/corify.sml
+++ b/src/corify.sml
@@ -244,6 +244,7 @@ fun corifyCon st (c, loc) =
       | L.CRecord (k, xcs) =>
         (L'.CRecord (corifyKind k, map (fn (c1, c2) => (corifyCon st c1, corifyCon st c2)) xcs), loc)
       | L.CConcat (c1, c2) => (L'.CConcat (corifyCon st c1, corifyCon st c2), loc)
+      | L.CFold _ => raise Fail "Corify CFold"
 
 fun corifyExp st (e, loc) =
     case e of
diff --git a/src/expl.sml b/src/expl.sml
index 8e9bdfed..952dc5da 100644
--- a/src/expl.sml
+++ b/src/expl.sml
@@ -52,6 +52,7 @@ datatype con' =
 
        | CRecord of kind * (con * con) list
        | CConcat of con * con
+       | CFold of kind * kind
 
 withtype con = con' located
 
diff --git a/src/expl_print.sml b/src/expl_print.sml
index aca89834..445a0fff 100644
--- a/src/expl_print.sml
+++ b/src/expl_print.sml
@@ -143,6 +143,7 @@ fun p_con' par env (c, _) =
                                               string "++",
                                               space,
                                               p_con env c2])
+      | CFold _ => string "fold"
         
 and p_con env = p_con' false env
 
diff --git a/src/expl_util.sml b/src/expl_util.sml
index 23329f3e..809bc1e1 100644
--- a/src/expl_util.sml
+++ b/src/expl_util.sml
@@ -138,6 +138,12 @@ fun mapfoldB {kind = fk, con = fc, bind} =
                          S.map2 (mfc ctx c2,
                               fn c2' =>
                                  (CConcat (c1', c2'), loc)))
+              | CFold (k1, k2) =>
+                S.bind2 (mfk k1,
+                         fn k1' =>
+                            S.map2 (mfk k2,
+                                    fn k2' =>
+                                       (CFold (k1', k2'), loc)))
     in
         mfc
     end
diff --git a/src/explify.sml b/src/explify.sml
index 79e3b07f..0a84c5fe 100644
--- a/src/explify.sml
+++ b/src/explify.sml
@@ -59,7 +59,7 @@ fun explifyCon (c, loc) =
 
       | L.CRecord (k, xcs) => (L'.CRecord (explifyKind k, map (fn (c1, c2) => (explifyCon c1, explifyCon c2)) xcs), loc)
       | L.CConcat (c1, c2) => (L'.CConcat (explifyCon c1, explifyCon c2), loc)
-      | L.CFold _ => raise Fail "Explify CFold"
+      | L.CFold (dom, ran) => (L'.CFold (explifyKind dom, explifyKind ran), loc)
 
       | L.CError => raise Fail ("explifyCon: CError at " ^ EM.spanToString loc)
       | L.CUnif (_, _, ref (SOME c)) => explifyCon c