refactor: make destination type mechanism extensible

1 files changed, 23 insertions, 4 deletions

diff --git a/src/parse_assoc_type.rs b/src/parse_assoc_type.rs
index 37fd78c..a255455 100644
--- a/src/parse_assoc_type.rs
+++ b/src/parse_assoc_type.rs
@@ -2,6 +2,7 @@ use proc_macro2::Span;
 use syn::spanned::Spanned;
 use syn::{GenericArgument, Ident, PathArguments, PathSegment, TraitItemType, Type};
 
+use crate::parse_trait_sig::TypeTransform;
 use crate::syn_utils::{find_in_type, trait_bounds};
 use crate::AssocTypeMatcher;
 
@@ -12,9 +13,27 @@ pub enum AssocTypeParseError {
     NoIntoBound,
 }
 
+pub enum DestType<'a> {
+    Into(&'a Type),
+}
+
+impl DestType<'_> {
+    pub fn get_dest(&self) -> Type {
+        match self {
+            DestType::Into(ty) => (*ty).clone(),
+        }
+    }
+
+    pub fn type_transformation(&self) -> TypeTransform {
+        match self {
+            DestType::Into(_) => TypeTransform::Into,
+        }
+    }
+}
+
 pub fn parse_assoc_type(
     assoc_type: &TraitItemType,
-) -> Result<(&Ident, &Type), (Span, AssocTypeParseError)> {
+) -> Result<(&Ident, DestType), (Span, AssocTypeParseError)> {
     for bound in trait_bounds(&assoc_type.bounds) {
         if let PathSegment {
             ident,
@@ -36,7 +55,7 @@ pub fn parse_assoc_type(
                         ));
                     }
 
-                    return Ok((&assoc_type.ident, into_type));
+                    return Ok((&assoc_type.ident, DestType::Into(into_type)));
                 }
             }
         }
@@ -49,7 +68,7 @@ mod tests {
     use quote::quote;
     use syn::{TraitItemType, Type};
 
-    use crate::parse_assoc_type::{parse_assoc_type, AssocTypeParseError};
+    use crate::parse_assoc_type::{parse_assoc_type, AssocTypeParseError, DestType};
 
     #[test]
     fn ok() {
@@ -60,7 +79,7 @@ mod tests {
 
         assert!(matches!(
             parse_assoc_type(&type1),
-            Ok((id, Type::Path(path)))
+            Ok((id, DestType::Into(Type::Path(path))))
             if id == "A" && path.path.is_ident("String")
         ));
     }