Merge pull request #70 from mist-go/fully-working-inheritance

Fully working inheritance & OOP

crates/codegen/src/class_decl.rs

@@ -1,106 +1,160 @@
+use std::collections::HashMap;
+
 use mist_parser::ast::*;
 
-use crate::Context;
+use crate::{Context, GenRust, GetRust, RustCodegen};
 
-use crate::{GenRust, GetRust, RustCodegen};
+pub struct ClassProcessedData {
+    visibility: Visibility,
+    name: Identifier,
+    generics: GenericsDecl,
+    inherits: Option<ExprPath>,
+    self_path: ExprPath,
+    self_ty: TypeExpr,
+    fields: Vec<Spanned<FieldDeclStmt>>,
+    constructor: Spanned<ClassConstructor>,
+    items: Vec<ClassItem>,
+    methods: Vec<Spanned<FunctionDecl>>,
+    v_table: Vec<Identifier>,
+    override_v_table: HashMap<Override, Vec<Identifier>>,
+}
 
-pub fn class_decl(
-    ctx: &mut Context,
-    cg: &mut RustCodegen,
+impl ClassProcessedData {
+    pub fn analyze(
+        visibility: &Visibility,
+        name: &Identifier,
+        generics: &GenericsDecl,
+        inherits: &Option<ExprPath>,
+        fields: &Vec<Spanned<FieldDeclStmt>>,
+        constructor: &Spanned<ClassConstructor>,
+        items: &Vec<ClassItem>,
+    ) -> Self {
+        let self_path = ExprPath(vec![ExprPathSegment {
+            ident: name.clone(),
+            generics: generics.clone().into(),
+        }]);
 
-    visibility: &Visibility,
-    name: &Identifier,
-    generics: &GenericsDecl,
-    inherits: &Option<TypeExpr>,
-    fields: &Vec<Spanned<FieldDeclStmt>>,
-    constructor: &Spanned<ClassConstructor>,
-    items: &Vec<ClassItem>,
-) {
-    let inherits = if let Some(inherits) = inherits {
-        let path = get_type_path(inherits);
-        ctx.expr_super = Some(path.clone());
-        Some((inherits, path))
-    } else {
-        None
-    };
+        let self_ty = get_type_from_path(&self_path);
 
-    // Struct decl
-    cg.addln(&format!(
-        "{}struct {}{} {{",
-        visibility.get_rust(),
-        name.clone().get_rust(),
-        generics.clone().get_rust()
-    ));
-    cg.indent += 1;
+        let methods = items
+            .iter()
+            .filter_map(|item| match item {
+                ClassItem::ImplDecl(_) => None,
+                ClassItem::Method(method) => Some(method.clone()),
+            })
+            .collect::<Vec<Spanned<FunctionDecl>>>();
 
-    cg.add_indentedln(
-        "pub _m_oop: (&'static [*const std::ffi::c_void; Self::__V_COUNT], *mut std::ffi::c_void),",
-    );
+        let mut v_table = Vec::new();
+        let mut override_v_table = std::collections::HashMap::new();
 
-    if let Some((inherits, _)) = inherits {
-        cg.add_indented("pub _super: Box<");
-        cg.add(&inherits.get_rust());
-        cg.addln(">,");
+        for method in &methods {
+            if matches!(method.item.visibility, Visibility::Public) {
+                match &method.item.is_override {
+                    None => {
+                        v_table.push(method.item.name.clone());
+                    }
+                    Some(override_spec) => {
+                        override_v_table
+                            .entry(override_spec.clone())
+                            .or_insert_with(Vec::new)
+                            .push(method.item.name.clone());
+                    }
+                }
+            }
+        }
+
+        ClassProcessedData {
+            visibility: visibility.clone(),
+            name: name.clone(),
+            generics: generics.clone(),
+            inherits: inherits.clone(),
+            self_path,
+            self_ty,
+            fields: fields.clone(),
+            constructor: constructor.clone(),
+            items: items.clone(),
+            methods,
+            v_table,
+            override_v_table,
+        }
     }
 
-    for field in fields.clone() {
-        cg.add_indentedln(&field.get_comment());
-        cg.add_indentedln(&field.item.decl.get_rust());
+    // ── Stage 2: Code Emission ───────────────────────────────────────
+
+    pub fn emit(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+        ctx.expr_super = self.inherits.clone();
+
+        self.emit_struct_decl(cg);
+        self.emit_impl_block(ctx, cg);
+        self.emit_impl_decls(ctx, cg);
+        self.emit_deref_impls(cg);
+
+        ctx.expr_super = None;
     }
 
-    cg.indent -= 1;
-    cg.addln("}\n");
+    fn emit_struct_decl(&self, cg: &mut RustCodegen) {
+        cg.addln(&format!(
+            "{}struct {}{} {{",
+            self.visibility.get_rust(),
+            self.name.get_rust(),
+            self.generics.get_rust()
+        ));
+        cg.indent += 1;
 
-    // Constructor
-    cg.addln(&format!(
-        "impl{} {}{} {{",
-        generics.clone().get_rust(),
-        name.clone().get_rust(),
-        format!(
-            "<{}>",
-            generics
-                .clone()
-                .0
-                .into_iter()
-                .map(|v| Generic::from(v).get_rust())
-                .collect::<Vec<_>>()
-                .join(", ")
-        )
-    ));
-    cg.indent += 1;
+        cg.add_indentedln(
+            "pub _m_oop: (&'static [*const std::ffi::c_void], *mut std::ffi::c_void),",
+        );
 
-    let methods = items
-        .clone()
-        .into_iter()
-        .filter_map(|item| match item {
-            ClassItem::ImplDecl(_) => None,
-            ClassItem::Method(method) => Some(method),
-        })
-        .collect::<Vec<_>>();
+        if let Some(ref inherits) = self.inherits {
+            cg.add_indented("pub _super: Box<");
+            cg.add(&get_type_from_path(inherits).get_rust());
+            cg.addln(">,");
+        }
 
-    let v_table = methods
-        .iter()
-        .filter_map(|method| match method.item.visibility {
-            Visibility::Public => Some((method.item.name.clone(), method.item.is_override)),
-            _ => None,
-        })
-        .collect::<Vec<_>>();
+        for field in &self.fields {
+            cg.add_indentedln(&field.get_comment());
+            cg.add_indentedln(&field.item.decl.get_rust());
+        }
 
-    // V TABLE
-    {
-        cg.add_indentedln(&format!("pub const __V_COUNT: usize = {};", v_table.len()));
+        cg.indent -= 1;
+        cg.addln("}\n");
+    }
 
-        for (i, method_name) in v_table.iter().enumerate() {
+    fn emit_impl_block(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+        cg.addln(&format!(
+            "impl{} {} {{",
+            self.generics.get_rust(),
+            self.self_ty.get_rust()
+        ));
+        cg.indent += 1;
+
+        self.emit_v_table(cg);
+
+        self.emit_super_v_table(cg);
+        self.emit_super_v_tests(cg);
+
+        self.emit_constructor(ctx, cg);
+        self.emit_methods(ctx, cg);
+
+        cg.indent -= 1;
+        cg.addln("}\n");
+    }
+
+    fn emit_v_table(&self, cg: &mut RustCodegen) {
+        for (i, method_name) in self.v_table.iter().enumerate() {
             cg.add_indentedln(&format!(
                 "pub const __FN_{}: usize = {i};",
-                method_name.0.0.to_uppercase()
+                method_name.0.to_uppercase()
             ));
         }
 
-        cg.add_indentedln("pub const __V_TABLE: [*const std::ffi::c_void; Self::__V_COUNT] = [");
+        cg.add_indentedln(&format!(
+            "pub const __V_TABLE: [*const std::ffi::c_void; {}] = [",
+            self.v_table.len()
+        ));
         cg.indent += 1;
 
-        for (method_name, _) in &v_table {
+        for method_name in &self.v_table {
             cg.add_indented("Self::__m_");
             cg.add(&method_name.get_rust());
             cg.add(" as *const std::ffi::c_void");
@@ -111,77 +165,115 @@ pub fn class_decl(
         cg.add_indentedln("];");
     }
 
-    // Super V Table
-    if let Some((inherits, inherit_path)) = &inherits {
-        cg.add_indented(&format!(
-            "pub const __SUPER_V_TABLE: [*const std::ffi::c_void; {}",
-            inherits.get_rust()
-        ));
-
-        cg.addln("::__V_COUNT] = {");
-        cg.indent += 1;
-
-        cg.add_indented("let mut table = ");
-        cg.add(&inherits.get_rust());
-        cg.addln("::__V_TABLE;");
-
-        for (name, is_override) in v_table {
-            if is_override {
-                cg.add_indentedln(&format!(
-                    "table[{}::__FN_{}] = Self::__m_{} as *const std::ffi::c_void;",
-                    inherits.get_rust(),
-                    name.0.to_uppercase(),
-                    name.get_rust()
-                ));
-            }
+    fn emit_super_v_table(&self, cg: &mut RustCodegen) {
+        if self.override_v_table.is_empty() {
+            return;
         }
 
-        cg.add_indentedln("table");
-
-        cg.indent -= 1;
-        cg.add_indentedln("};");
-
-        cg.add_indentedln("const fn __test_vt() {");
+        cg.add_indentedln(&format!(
+            "pub const __SUPER_V_TABLES: [&'static [*const std::ffi::c_void]; {}] = [",
+            self.override_v_table.len()
+        ));
         cg.indent += 1;
 
-        for i in &methods {
-            if i.item.is_override {
-                let mut params = i
-                    .item
-                    .params
-                    .clone()
-                    .0
-                    .into_iter()
-                    .filter_map(|v| v.type_)
-                    .collect::<Vec<_>>();
-
-                if params.len() == 0 {
-                    continue;
+        for (override_tier, overriden_method_idents) in &self.override_v_table {
+            let target_path = match &override_tier.0 {
+                Some(path) => path.clone(),
+                None => {
+                    if let Some(parent_path) = &self.inherits {
+                        parent_path.clone()
+                    } else {
+                        continue; // Safeguard if AST has a dangling override without inheritance
+                    }
                 }
+            };
 
-                match params.remove(0) {
-                    TypeExpr::Ref { mutable, .. } => {
-                        cg.add_indented(&inherit_path.get_rust());
-                        cg.add("::__m_");
-                        cg.add(&i.item.name.get_rust());
+            let target_rust_path = target_path.get_rust();
+
+            // 2. Emit the block for this specific index table
+            cg.add_indentedln("&{");
+            cg.indent += 1;
+
+            // Initialize this sub-table with the target parent class's base vtable
+            cg.add_indentedln(&format!("let mut table = {}::__V_TABLE;", target_rust_path));
+
+            // Patch the slots for every method registered under this specific override tier
+            for method_ident in overriden_method_idents {
+                cg.add_indentedln(&format!(
+                    "table[{}::__FN_{}] = {}::__m_{} as *const std::ffi::c_void;",
+                    target_rust_path,
+                    method_ident.0.to_uppercase(),
+                    self.self_path.get_rust(),
+                    method_ident.get_rust()
+                ));
+            }
+
+            cg.add_indentedln("table");
+            cg.indent -= 1;
+            cg.add_indentedln("},");
+        }
+
+        cg.indent -= 1;
+        cg.add_indentedln("];");
+    }
+
+    fn emit_super_v_tests(&self, cg: &mut RustCodegen) {
+        cg.add_indentedln(&format!("const fn __test_vt() {{"));
+        cg.indent += 1;
+
+        for (override_tier, _) in self.override_v_table.iter() {
+            let target_path = match &override_tier.0 {
+                Some(path) => path.clone(),
+
+                None => {
+                    if let Some(parent_path) = &self.inherits {
+                        parent_path.clone()
+                    } else {
+                        continue; // Safeguard if AST has a dangling override without inheritance
+                    }
+                }
+            };
+
+            let target_rust_path = target_path.get_rust();
+
+            for method in &self.methods {
+                if method.item.is_override.as_ref() == Some(override_tier) {
+                    let mut params = method
+                        .item
+                        .params
+                        .0
+                        .clone()
+                        .into_iter()
+                        .filter_map(|v| v.type_)
+                        .collect::<Vec<_>>();
+
+                    if params.is_empty() {
+                        continue;
+                    }
+
+                    if let TypeExpr::Ref { mutable, .. } = params.remove(0) {
+                        cg.add_indented(&format!("{}::__m_", target_rust_path));
+                        cg.add(&method.item.name.get_rust());
                         cg.add(" as ");
 
                         params.insert(
                             0,
                             TypeExpr::Ref {
                                 lifetime: None,
-                                mutable: mutable,
-                                ty: Box::new((*inherits).clone()),
+                                mutable,
+                                ty: Box::new(get_type_from_path(&target_path)),
                             },
                         );
 
                         cg.add(
-                            &TypeExpr::StaticFn(params, i.item.return_type.clone().map(Box::new))
-                                .get_rust(),
+                            &TypeExpr::StaticFn(
+                                params,
+                                method.item.return_type.clone().map(Box::new),
+                            )
+                            .get_rust(),
                         );
                         cg.addln(";");
                     }
-                    _ => {}
                 }
             }
         }
@@ -190,94 +282,20 @@ pub fn class_decl(
         cg.add_indentedln("}");
     }
 
-    let constructor_comment = constructor.get_comment();
+    fn emit_constructor(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+        let constructor_comment = self.constructor.get_comment();
 
-    cg.add_indentedln("#[allow(invalid_value)]");
-    cg.add_indentedln(&constructor_comment);
+        cg.add_indentedln("#[allow(invalid_value)]");
+        cg.add_indentedln(&constructor_comment);
 
-    (fields, constructor, inherits.is_some()).gen_rust(ctx, cg);
-
-    for mut method in methods {
-        match method.item.visibility {
-            Visibility::Public => {
-                if !method.item.is_override {
-                    gen_method_point(&method.item, ctx, cg);
-                }
-
-                method.item.name.0.insert_str(0, "__m_");
-            }
-            _ => {}
-        }
-
-        method.gen_rust(ctx, cg);
-    }
-
-    cg.indent -= 1;
-    cg.addln("}\n");
-
-    for item in items {
-        match item {
-            ClassItem::ImplDecl(impl_) => {
-                let mut impl_ = impl_.clone();
-
-                impl_.item.trait_ = Some(impl_.item.target);
-                impl_.item.target = TypeExpr::Path(Path(vec![name.clone()]), None);
-
-                impl_.gen_rust(ctx, cg);
-            }
-            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("}");
-    }
-
-    ctx.expr_super = None;
-}
-
-impl GenRust
-    for (
-        &Vec<Spanned<FieldDeclStmt>>,
-        &Spanned<ClassConstructor>,
-        bool,
-    )
-{
-    fn gen_rust(&self, ctx: &mut Context, cg: &mut RustCodegen) {
         cg.add_indented(&format!(
             "{}fn new{}(",
-            self.1.item.visibility.get_rust(),
-            self.1.item.generics.get_rust()
+            self.constructor.item.visibility.get_rust(),
+            self.constructor.item.generics.get_rust()
         ));
 
         let params = self
-            .1
+            .constructor
             .item
             .params
             .0
@@ -294,7 +312,6 @@ impl GenRust
             if *i > 0 {
                 cg.add(", ");
             }
-
             param.gen_rust(ctx, cg);
         }
 
@@ -305,40 +322,54 @@ impl GenRust
         cg.add_indentedln("let this_ptr = &mut *this as *mut Self as *mut std::ffi::c_void;");
         cg.add_indentedln("this._m_oop = (&Self::__V_TABLE, this_ptr);");
 
-        for field in self.0 {
+        // Inline field declarations and initializers
+        for field in &self.fields {
             let comment = field.get_comment();
 
             if let Some(init) = &field.item.init {
                 cg.add_indentedln(&comment);
-
                 cg.add_indentedln(&format!("this.{} = ", field.item.decl.name.get_rust()));
-
                 init.gen_rust(ctx, cg);
             }
         }
 
-        cg.add_indented(&format!("this.constructor("));
-
-        for (i, param) in params {
-            if i > 0 {
+        cg.add_indented("this.constructor(");
+        for (i, param) in &params {
+            if *i > 0 {
                 cg.add(", ");
             }
-
             ctx.expr_ensure_semicolon = false;
             param.name.gen_rust(ctx, cg);
         }
-
         cg.addln(");");
 
-        if self.2 {
-            cg.add_indentedln("this._super._m_oop.0 = &Self::__SUPER_V_TABLE;");
+        if self.inherits.is_some() && !self.override_v_table.is_empty() {
+            for (idx, (override_tier, _)) in self.override_v_table.iter().enumerate() {
+                match &override_tier.0 {
+                    // Direct base class layout updates
+                    None => {
+                        cg.add_indentedln(&format!(
+                            "this._super._m_oop.0 = Self::__SUPER_V_TABLES[{}];",
+                            idx
+                        ));
+                    }
+                    // Deep ancestor trait table updates
+                    Some(path) => {
+                        cg.add_indentedln(&format!(
+                            "(|v: &mut {}| {{v._m_oop.0 = Self::__SUPER_V_TABLES[{}];}})(&mut this);",
+                            path.get_rust(),
+                            idx
+                        ));
+                    }
+                }
+            }
         }
 
         cg.add_indentedln("this");
-
         cg.indent -= 1;
         cg.add_indentedln("}\n");
 
+        // Generate matching inner initialization body block
         let mut constructor_params = vec![VarDecl {
             name: Pattern::Path(false, Path(vec![Identifier(String::from("self"))])),
             type_: Some(TypeExpr::Ref {
@@ -351,23 +382,117 @@ impl GenRust
             }),
         }];
 
-        constructor_params.append(&mut self.1.item.params.0.clone());
+        constructor_params.append(&mut self.constructor.item.params.0.clone());
 
         Spanned {
-            line: self.1.line,
-            column: self.1.column,
+            line: self.constructor.line,
+            column: self.constructor.column,
             item: FunctionDecl {
-                visibility: self.1.item.visibility.clone(),
-                is_override: false,
+                visibility: self.constructor.item.visibility.clone(),
+                is_override: None,
                 name: Identifier(String::from("constructor")),
-                generics: self.1.item.generics.clone(),
+                generics: self.constructor.item.generics.clone(),
                 params: ParamList(constructor_params),
                 return_type: Some(TypeExpr::Tuple(Vec::new())),
-                body: Some(self.1.item.body.clone()),
+                body: Some(self.constructor.item.body.clone()),
             },
         }
         .gen_rust(ctx, cg);
     }
+
+    fn emit_methods(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+        for method in &self.methods {
+            match method.item.visibility {
+                Visibility::Public => {
+                    if method.item.is_override.is_none() {
+                        gen_method_point(&method.item, ctx, cg);
+                    }
+
+                    let mut prefixed = method.clone();
+                    prefixed.item.name.0.insert_str(0, "__m_");
+                    prefixed.gen_rust(ctx, cg);
+                }
+                _ => {
+                    method.gen_rust(ctx, cg);
+                }
+            }
+        }
+    }
+
+    fn emit_impl_decls(&self, ctx: &mut Context, cg: &mut RustCodegen) {
+        for item in &self.items {
+            if let ClassItem::ImplDecl(impl_) = item {
+                let mut impl_ = impl_.clone();
+                impl_.item.trait_ = Some(impl_.item.target);
+                impl_.item.target = TypeExpr::Path(Path(vec![self.name.clone()]), None);
+                impl_.gen_rust(ctx, cg);
+            }
+        }
+    }
+
+    fn emit_deref_impls(&self, cg: &mut RustCodegen) {
+        if let Some(ref inherits) = self.inherits {
+            let generics_str = self.generics.get_rust();
+            let generics_expr_str = Generics::from(self.generics.clone()).get_rust();
+
+            cg.add(&format!(
+                "impl{} std::ops::Deref for {}{}",
+                generics_str,
+                self.name.get_rust(),
+                generics_expr_str
+            ));
+
+            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("}");
+
+            cg.add(&format!(
+                "impl{} std::ops::DerefMut for {}{}",
+                generics_str,
+                self.name.get_rust(),
+                generics_expr_str
+            ));
+
+            cg.addln(" {");
+            cg.indent += 1;
+
+            cg.add_indentedln("fn deref_mut(&mut self) -> &mut Self::Target { &mut self._super }");
+
+            cg.indent -= 1;
+            cg.addln("}");
+        }
+    }
+}
+
+pub fn class_decl(
+    ctx: &mut Context,
+    cg: &mut RustCodegen,
+    visibility: &Visibility,
+    name: &Identifier,
+    generics: &GenericsDecl,
+    inherits: &Option<ExprPath>,
+    fields: &Vec<Spanned<FieldDeclStmt>>,
+    constructor: &Spanned<ClassConstructor>,
+    items: &Vec<ClassItem>,
+) {
+    let data = ClassProcessedData::analyze(
+        visibility,
+        name,
+        generics,
+        inherits,
+        fields,
+        constructor,
+        items,
+    );
+    data.emit(ctx, cg);
 }
 
 fn construct_pattern(pat: &Pattern, idx: usize) -> Pattern {
@@ -386,11 +511,22 @@ pub fn gen_method_point(method: &FunctionDecl, ctx: &mut Context, cg: &mut RustC
         method.generics.get_rust(),
     ));
 
-    for (i, param) in method.params.0.iter().enumerate() {
-        if i > 0 {
+    let params = method
+        .params
+        .0
+        .clone()
+        .into_iter()
+        .enumerate()
+        .map(|(idx, mut v)| {
+            v.name = construct_pattern(&v.name, idx);
+            (idx, v)
+        })
+        .collect::<Vec<_>>();
+
+    for (i, param) in &params {
+        if *i > 0 {
             cg.add(", ");
         }
-
         param.gen_rust(ctx, cg);
     }
 
@@ -421,7 +557,9 @@ pub fn gen_method_point(method: &FunctionDecl, ctx: &mut Context, cg: &mut RustC
         .filter_map(|v| v.type_)
         .collect();
 
-    param_types.remove(0);
+    if !param_types.is_empty() {
+        param_types.remove(0);
+    }
 
     param_types.insert(
         0,
@@ -439,24 +577,31 @@ pub fn gen_method_point(method: &FunctionDecl, ctx: &mut Context, cg: &mut RustC
     );
 
     cg.add(&TypeExpr::StaticFn(param_types, method.return_type.clone().map(Box::new)).get_rust());
-
     cg.addln(" = std::mem::transmute(func_ptr);");
 
-    cg.add_indentedln("func(self._m_oop.1)");
+    cg.add_indented("func(self._m_oop.1");
 
-    cg.indent -= 1;
-    cg.add_indentedln("}");
-
-    cg.indent -= 1;
-    cg.add_indentedln("}");
-}
-
-pub fn get_type_path(ty: &TypeExpr) -> Path {
-    match ty {
-        TypeExpr::Path(p, _) => p.clone(),
-        TypeExpr::Dyn(v) => get_type_path(v),
-        TypeExpr::Ref { ty, .. } => get_type_path(ty),
-        TypeExpr::UnsafePtr { ty, .. } => get_type_path(ty),
-        _ => unimplemented!(),
+    for (i, param) in &params {
+        if *i == 0 {
+            continue; // self._m_oop.1 already fulfills it
+        }
+        cg.add(", ");
+        ctx.expr_ensure_semicolon = false;
+        param.name.gen_rust(ctx, cg);
     }
+
+    cg.addln(")");
+
+    cg.indent -= 1;
+    cg.add_indentedln("}");
+
+    cg.indent -= 1;
+    cg.add_indentedln("}");
+}
+
+pub fn get_type_from_path(path: &ExprPath) -> TypeExpr {
+    TypeExpr::Path(
+        Path(path.0.iter().map(|v| v.ident.clone()).collect::<Vec<_>>()),
+        path.0.last().unwrap().generics.clone(),
+    )
 }

crates/codegen/src/expr.rs

@@ -20,17 +20,7 @@ impl GetRust for ExprPath {
             if self.0[0].ident.0 == "super" && self.0.len() == 1 {
                 a.0[0].ident.0 = String::from("self._super");
             } else if self.0[0].ident.0 == "Super" {
-                a.0[0].ident = path.0[0].clone();
-
-                if path.0.len() > 1 {
-                    a.0.splice(
-                        1..1,
-                        path.0.clone().into_iter().skip(1).map(|v| ExprPathSegment {
-                            ident: v,
-                            generics: None,
-                        }),
-                    );
-                }
+                a.0[0] = path.0[0].clone();
             }
         }
 

crates/codegen/src/lib.rs

@@ -7,7 +7,7 @@ use mist_parser::ast::*;
 
 pub struct Context {
     pub expr_ensure_semicolon: bool,
-    pub expr_super: Option<Path>,
+    pub expr_super: Option<ExprPath>,
 }
 
 pub trait GenRust {

crates/parser/src/ast/expr.rs

@@ -79,19 +79,19 @@ pub enum Prefix {
     Neg,
 }
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub struct ExprPathSegment {
     pub ident: Identifier,
     pub generics: Option<Generics>,
 }
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub struct ExprPath(pub Vec<ExprPathSegment>);
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub struct Generics(pub Vec<Generic>);
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub enum Generic {
     Lifetime(Identifier),
     Type(TypeExpr),

crates/parser/src/ast/mod.rs

@@ -8,16 +8,16 @@ pub use expr::*;
 pub use statement::*;
 pub use top_level::*;
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub struct Path(pub Vec<Identifier>);
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub struct Identifier(pub String);
 
 #[derive(Debug, Clone, Serialize, Default)]
 pub struct ParamList(pub Vec<VarDecl>);
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
 pub enum TypeExpr {
     Ref {
         lifetime: Option<Identifier>,
@@ -51,6 +51,22 @@ impl From<GenericDecl> for Generic {
     }
 }
 
+impl Into<Option<Generics>> for GenericsDecl {
+    fn into(self) -> Option<Generics> {
+        if self.0.len() == 0 {
+            None
+        } else {
+            Some(self.into())
+        }
+    }
+}
+
+impl From<GenericsDecl> for Generics {
+    fn from(value: GenericsDecl) -> Self {
+        Self(value.0.into_iter().map(Generic::from).collect())
+    }
+}
+
 impl<T> Spanned<T> {
     pub fn get_comment(&self) -> String {
         format!("/* {}:{} */", self.line, self.column)

crates/parser/src/ast/top_level.rs

@@ -54,7 +54,7 @@ pub enum TopLevelKind {
         visibility: Visibility,
         name: Identifier,
         generics: GenericsDecl,
-        inherits: Option<TypeExpr>,
+        inherits: Option<ExprPath>,
         fields: Vec<Spanned<FieldDeclStmt>>,
         constructor: Spanned<ClassConstructor>,
         items: Vec<ClassItem>,
@@ -91,10 +91,13 @@ pub struct ClassConstructor {
     pub body: Block,
 }
 
+#[derive(Debug, Clone, Serialize, PartialEq, Eq, Hash)]
+pub struct Override(pub Option<ExprPath>);
+
 #[derive(Debug, Clone, Serialize)]
 pub struct FunctionDecl {
     pub visibility: Visibility,
-    pub is_override: bool,
+    pub is_override: Option<Override>,
     pub name: Identifier,
     pub generics: GenericsDecl,
     pub params: ParamList,

crates/parser/src/grammar.pest

@@ -294,7 +294,7 @@ class_item = _{
 }
 
 class_decl = {
-    visibility? ~ "class" ~ identifier ~ generics_decl? ~ (":" ~ type_expr)? ~ "{" ~ class_fields ~ class_constructor ~ class_item* ~ "}"
+    visibility? ~ "class" ~ identifier ~ generics_decl? ~ (":" ~ expr_path)? ~ "{" ~ class_fields ~ class_constructor ~ class_item* ~ "}"
 }
 
 // ======================================================
@@ -325,7 +325,7 @@ trait_decl = {
 // FUNCTIONS
 // ======================================================
 
-override_kw = { "override" }
+override_kw = { "override" ~ ("(" ~ expr_path ~ ")")? }
 
 function_decl = {
     visibility? ~ override_kw? ~ "fn" ~ identifier ~ generics_decl? ~ "(" ~ method_args ~ ")" ~ type_expr? ~ (block | semicolon)

crates/parser/src/parser/items/function.rs

@@ -13,7 +13,7 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FunctionDecl {
         ast_ensure!(pair, Rule::function_decl => {
         let mut inner = pair.into_inner();
             let visibility = Visibility::try_from(&mut inner);
-            let is_override: AstResult<bool> = Ok(listen_rule(&mut inner, Rule::override_kw));
+            let is_override = consume_rule(&mut inner, Rule::override_kw).map(Override::try_from).transpose();
             let name = Identifier::try_from(inner.next().unwrap());
 
             let generics = consume_rule(&mut inner, Rule::generics_decl)
@@ -77,3 +77,13 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FunctionDecl {
         })
     }
 }
+
+impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Override {
+    type Error = AstError<'a, Self>;
+
+    fn try_from(pair: pest::iterators::Pair<'a, Rule>) -> Result<Self, Self::Error> {
+        ast_ensure!(pair, Rule::override_kw => {
+            ast_expr!(Override(pair.into_inner().next().map(ExprPath::try_from).transpose()))
+        })
+    }
+}

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

@@ -69,8 +69,8 @@ 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)
+                inherits: consume_rule(&mut inner, Rule::expr_path)
+                    .map(ExprPath::try_from)
                     .transpose(),
 
                 fields: collect_recovered(inner.next().unwrap().into_inner()),

mist-test/src/items/class_test.mist

@@ -1,5 +1,6 @@
-pub class Animal {
+pub class Animal<T> {
     pub name String;
+    pub val T;
 
     constructor() {
         self.name = "Rex".to_string();
@@ -14,20 +15,42 @@ pub class Animal {
     }
 }
 
-pub class Dog : Animal {
+pub class Mammal<T> : Animal<T> {
     constructor() {
         unsafe {
             std::ptr::write(&mut super, Super::new());
         }
     }
 
-    pub override fn speak(*self) {
+    pub fn args_test(*self, x i32, y *str) {}
+
+    pub fn returning<'a>(*self) *'a str {
+        "Mammal"
+    }
+}
+
+pub class Dog : Mammal<i32> {
+    constructor() {
+        unsafe {
+            std::ptr::write(&mut super, Super::new());
+        }
+    }
+
+    pub override(Animal<i32>) fn speak(*self) {
         println!("Woof!");
     }
+
+    pub override fn returning(*self) *str {
+        "Dog"
+    }
 }
 
 pub fn run_tests() {
     let dawg = Dog::new();
 
+    dawg.args_test(10, "hello");
+
     dawg.test_speak();
+
+    println!("{}", dawg.returning());
 }