Merge pull request #53 from mist-go/inheritance

Inheritance

crates/codegen/src/lib.rs

@@ -113,6 +113,7 @@ impl GenRust for Attribute {
             }
             Self::List { path, items } => {
                 cg.add(&path.get_rust());
+                cg.add("(");
                 for (i, item) in items.iter().enumerate() {
                     if i > 0 {
                         cg.add(", ");
@@ -120,6 +121,7 @@ impl GenRust for Attribute {
 
                     item.gen_rust(ctx, cg);
                 }
+                cg.add(")");
             }
         }
     }

crates/codegen/src/top_level.rs

@@ -325,6 +325,7 @@ impl GenRust for TopLevelKind {
                 visibility,
                 name,
                 generics,
+                inherits,
                 fields,
                 constructor,
                 items,
@@ -338,6 +339,12 @@ impl GenRust for TopLevelKind {
                 ));
                 cg.indent += 1;
 
+                if let Some(inherits) = inherits {
+                    cg.add_indented("pub _super: ");
+                    cg.add(&inherits.get_rust());
+                    cg.addln(",");
+                }
+
                 for field in fields.clone() {
                     cg.add_indentedln(&field.get_comment());
                     cg.add_indentedln(&field.item.decl.get_rust());
@@ -395,6 +402,38 @@ impl GenRust for TopLevelKind {
                         ClassItem::Method(_) => {}
                     }
                 }
+
+                if let Some(inherits) = inherits {
+                    cg.add("impl std::ops::Deref for ");
+                    cg.add(&name.get_rust());
+
+                    cg.addln(" {");
+                    cg.indent += 1;
+
+                    cg.add_indented("type Target = ");
+                    cg.add(&inherits.get_rust());
+                    cg.addln(";");
+
+                    cg.add_indentedln("fn deref(&self) -> &Self::Target {&self._super}");
+
+                    cg.indent -= 1;
+                    cg.addln("}");
+
+                    // Mut
+
+                    cg.add("impl std::ops::DerefMut for ");
+                    cg.add(&name.get_rust());
+
+                    cg.addln(" {");
+                    cg.indent += 1;
+
+                    cg.add_indentedln(
+                        "fn deref_mut(&mut self) -> &mut Self::Target {&mut self._super}",
+                    );
+
+                    cg.indent -= 1;
+                    cg.addln("}");
+                }
             }
         }
     }

crates/parser/src/ast/top_level.rs

@@ -54,6 +54,7 @@ pub enum TopLevelKind {
         visibility: Visibility,
         name: Identifier,
         generics: GenericsDecl,
+        inherits: Option<TypeExpr>,
         fields: Vec<Spanned<FieldDeclStmt>>,
         constructor: Spanned<ClassConstructor>,
         items: Vec<ClassItem>,

crates/parser/src/grammar.pest

@@ -285,7 +285,7 @@ class_item = _{
 }
 
 class_decl = {
-    visibility? ~ "class" ~ identifier ~ generics_decl? ~ "{" ~ class_fields ~ class_constructor ~ class_item* ~ "}"
+    visibility? ~ "class" ~ identifier ~ generics_decl? ~ (":" ~ type_expr)? ~ "{" ~ class_fields ~ class_constructor ~ class_item* ~ "}"
 }
 
 // ======================================================

crates/parser/src/parser/items/attribute.rs

@@ -28,11 +28,11 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Attribute {
                     }
 
                     Some(next) => match next.as_rule() {
-                        Rule::primary => {
+                        Rule::literal => {
                             // #[path = literal]
                             Ok(Attribute::NameValue {
                                 path,
-                                value: inner.next().unwrap().try_into().get()?,
+                                value: next.try_into().get()?,
                             })
                         }
 

crates/parser/src/parser/items/mod.rs

@@ -69,6 +69,10 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for TopLevelKind {
                     .transpose()
                     .map(|v| v.unwrap_or_default()),
 
+                inherits: consume_rule(&mut inner, Rule::type_expr)
+                    .map(TypeExpr::try_from)
+                    .transpose(),
+
                 fields: collect_recovered(inner.next().unwrap().into_inner()),
 
                 constructor: inner.next().unwrap().try_into(),