From 45f49378fa12cddd0d2dac31b671b9b075ffe4d0 Mon Sep 17 00:00:00 2001
From: Michael Sippel <micha@fragmental.art>
Date: Tue, 3 Oct 2023 03:34:55 +0200
Subject: [PATCH] is_syntactic_subtype(): remove option in Err variant

---
 src/subtype.rs      | 8 ++++----
 src/test/subtype.rs | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/subtype.rs b/src/subtype.rs
index 8f398b1..8c46752 100644
--- a/src/subtype.rs
+++ b/src/subtype.rs
@@ -19,20 +19,20 @@ impl TypeTerm {
         None
     }
 
-    pub fn is_syntactic_subtype_of(&self, expected_type: &TypeTerm) -> Result<usize, Option<(usize, usize)>> {
+    pub fn is_syntactic_subtype_of(&self, expected_type: &TypeTerm) -> Result<usize, (usize, usize)> {
         if let Some((first_match, provided_type)) = self.is_semantic_subtype_of( expected_type ) {
             let provided_lnf = provided_type.get_lnf_vec();
             let expected_lnf = expected_type.clone().get_lnf_vec();
 
             for i in 0 .. usize::min( provided_lnf.len(), expected_lnf.len() ) {
                 if provided_lnf[i] != expected_lnf[i] {
-                    return Err(Some((first_match, first_match+i)))
+                    return Err((first_match, first_match+i))
                 }
             }
 
             Ok(first_match)
         } else {
-            Err(None)
+            Err((0,0))
         }
     }
 
@@ -43,7 +43,7 @@ impl TypeTerm {
         t.is_semantic_subtype_of(self)
     }
 
-    pub fn is_syntactic_supertype_of(&self, t: &TypeTerm) -> Result<usize, Option<(usize, usize)>> {
+    pub fn is_syntactic_supertype_of(&self, t: &TypeTerm) -> Result<usize, (usize, usize)> {
         t.is_syntactic_subtype_of(self)
     }
 }
diff --git a/src/test/subtype.rs b/src/test/subtype.rs
index 54ad397..08cc5c7 100644
--- a/src/test/subtype.rs
+++ b/src/test/subtype.rs
@@ -62,7 +62,7 @@ fn test_syntactic_subtype() {
             .is_syntactic_subtype_of(
                 &dict.parse("C~G").expect("parse errror")  
             ),
-        Err(Some((2,3)))
+        Err((2,3))
     );
 
     assert_eq!(
@@ -70,7 +70,7 @@ fn test_syntactic_subtype() {
             .is_syntactic_subtype_of(
                 &dict.parse("G~F~K").expect("parse errror")  
             ),
-        Err(None)
+        Err((0,0))
     );
 
     assert_eq!(