Managed diphtongues

1 files changed, 24 insertions, 11 deletions

diff --git a/src/lib/modifiers/nasal.ml b/src/lib/modifiers/nasal.ml
index da24863..b9874c9 100644
--- a/src/lib/modifiers/nasal.ml
+++ b/src/lib/modifiers/nasal.ml
@@ -9,15 +9,28 @@ let process
     let module T = (val m:Sounds.T with type t = el) in
     let (((v1, v2), c) , ending) = init in
     let ending = Option.bind ending (fun x -> x) in
-    match ending with
-    | None -> init
-    | Some ending ->
-      match T.is_nasal ending with
-      | false -> init
-      | true ->
-        (* Remove the ending consonant, and transform the voyel into
-           the nasal form  *)
-        ( ( (T.nasal v1, T.nasal v2)
-          , c )
-        , None )
+    let opening = Option.map (fun v -> v.Sig.opening) c in
+    let is_voyel = T.is_voyel v1 && T.is_voyel v2 in
+    match ending, is_voyel, opening with
+    | Some ending, _, _ when T.is_nasal ending ->
+      (* Remove the ending consonant, and transform the voyel into
+         the nasal form  *)
+      ( ( (T.nasal v1, T.nasal v2)
+        , c )
+      , None )
+    | None, false, Some (opening::tl) when T.is_nasal opening ->
+      (* If there is no voyel here, transform the opening consonant as an
+         ending consonant for the next syllabus *)
+      let c = Option.map
+          (fun c ->
+             { c with
+               Sig.opening = tl
+             ; Sig.ending = (Some (Some opening))
+             }) c in
+      ( ( (T.nasal v1, T.nasal v2)
+        , c )
+      , None )
+    | _ ->
+      (* Return the element unchanged *)
+      init