improve encode_type_to_symbol to handle complex types

src/main.rs

@@ -96,9 +96,31 @@ struct LdmcPrimCMorphism {
 fn encode_type_to_symbol(dict: &mut impl TypeDict, t: &laddertypes::TypeTerm)-> String {
     match t {
         laddertypes::TypeTerm::Char(c) => {
-            format!("{}", (*c as u64))
+            match c {
+                '.' => format!("_dot_"),
+                _ =>
+                format!("{}", (*c as u64))
+            }
         },
-        t => dict.unparse(t)
+        laddertypes::TypeTerm::Num(n) => {
+            format!("{}", n)
+        }
+        laddertypes::TypeTerm::TypeID(ty_id) => {
+            if let Some(name) = dict.get_typename(ty_id) {
+                format!("{}", name.replace(".", "_dot_"))
+            } else {
+                format!("")
+            }
+        }
+        laddertypes::TypeTerm::Ladder(rs) |
+        laddertypes::TypeTerm::App(rs) => {
+            let mut s = String::new();
+            for r in rs {
+                s.push('_');
+                s.push_str(&encode_type_to_symbol(dict, r));
+            }
+            s
+        }
     }
 }