Add Trait, Subsume

compiler/erg_compiler/context/eval.rs

@@ -274,7 +274,10 @@ impl Context {
                         })?
                         .clone();
                     let args = self.eval_args(&call.args, __name__)?;
-                    Ok(subr.call(args, __name__.cloned()))
+                    subr.call(args, __name__.cloned()).map_err(|mut e| {
+                        e.loc = call.loc();
+                        EvalError::new(e, self.caused_by())
+                    })
                 }
                 Accessor::Attr(_attr) => todo!(),
                 Accessor::TupleAttr(_attr) => todo!(),

compiler/erg_compiler/context/initialize/const_func.rs

@@ -2,8 +2,11 @@ use std::mem;
 
 use erg_common::Str;
 
+use erg_common::astr::AtomicStr;
+use erg_common::color::{RED, RESET};
+use erg_common::error::{ErrorCore, ErrorKind, Location};
 use erg_type::constructors::{and, mono};
-use erg_type::value::{TypeKind, TypeObj, ValueObj};
+use erg_type::value::{EvalValueResult, TypeKind, TypeObj, ValueObj};
 use erg_type::Type;
 use erg_type::ValueArgs;
 
@@ -20,31 +23,61 @@ fn value_obj_to_t(value: ValueObj) -> TypeObj {
 }
 
 /// Requirement: Type, Impl := Type -> ClassType
-pub fn class_func(mut args: ValueArgs, __name__: Option<Str>) -> ValueObj {
-    let require = args.remove_left_or_key("Requirement").unwrap();
+pub fn class_func(mut args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
+    let require = args.remove_left_or_key("Requirement").ok_or_else(|| {
+        ErrorCore::new(
+            line!() as usize,
+            ErrorKind::KeyError,
+            Location::Unknown,
+            AtomicStr::from(format!("{RED}Requirement{RESET} is not passed")),
+            None,
+        )
+    })?;
     let require = value_obj_to_t(require);
     let impls = args.remove_left_or_key("Impl");
     let impls = impls.map(value_obj_to_t);
     let t = mono(__name__.unwrap_or(Str::ever("<Lambda>")));
-    ValueObj::gen_t(TypeKind::Class, t, require, impls, None)
+    Ok(ValueObj::gen_t(TypeKind::Class, t, require, impls, None))
 }
 
 /// Super: Type, Impl := Type, Additional := Type -> ClassType
-pub fn inherit_func(mut args: ValueArgs, __name__: Option<Str>) -> ValueObj {
-    let sup = args.remove_left_or_key("Super").unwrap();
+pub fn inherit_func(mut args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
+    let sup = args.remove_left_or_key("Super").ok_or_else(|| {
+        ErrorCore::new(
+            line!() as usize,
+            ErrorKind::KeyError,
+            Location::Unknown,
+            AtomicStr::from(format!("{RED}Super{RESET} is not passed")),
+            None,
+        )
+    })?;
     let sup = value_obj_to_t(sup);
     let impls = args.remove_left_or_key("Impl");
     let impls = impls.map(value_obj_to_t);
     let additional = args.remove_left_or_key("Additional");
     let additional = additional.map(value_obj_to_t);
     let t = mono(__name__.unwrap_or(Str::ever("<Lambda>")));
-    ValueObj::gen_t(TypeKind::Subclass, t, sup, impls, additional)
+    Ok(ValueObj::gen_t(
+        TypeKind::Subclass,
+        t,
+        sup,
+        impls,
+        additional,
+    ))
 }
 
 /// Class: ClassType -> ClassType (with `InheritableType`)
 /// This function is used by the compiler to mark a class as inheritable and does nothing in terms of actual operation.
-pub fn inheritable_func(mut args: ValueArgs, __name__: Option<Str>) -> ValueObj {
-    let class = args.remove_left_or_key("Class").unwrap();
+pub fn inheritable_func(mut args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
+    let class = args.remove_left_or_key("Class").ok_or_else(|| {
+        ErrorCore::new(
+            line!() as usize,
+            ErrorKind::KeyError,
+            Location::Unknown,
+            AtomicStr::from(format!("{RED}Class{RESET} is not passed")),
+            None,
+        )
+    })?;
     match class {
         ValueObj::Type(TypeObj::Generated(mut gen)) => {
             if let Some(typ) = &mut gen.impls {
@@ -59,8 +92,52 @@ pub fn inheritable_func(mut args: ValueArgs, __name__: Option<Str>) -> ValueObj
             } else {
                 gen.impls = Some(Box::new(TypeObj::Builtin(mono("InheritableType"))));
             }
-            ValueObj::Type(TypeObj::Generated(gen))
+            Ok(ValueObj::Type(TypeObj::Generated(gen)))
         }
         _ => todo!(),
     }
 }
+
+/// Requirement: Type, Impl := Type -> ClassType
+pub fn trait_func(mut args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
+    let require = args.remove_left_or_key("Requirement").ok_or_else(|| {
+        ErrorCore::new(
+            line!() as usize,
+            ErrorKind::KeyError,
+            Location::Unknown,
+            AtomicStr::from(format!("{RED}Requirement{RESET} is not passed")),
+            None,
+        )
+    })?;
+    let require = value_obj_to_t(require);
+    let impls = args.remove_left_or_key("Impl");
+    let impls = impls.map(value_obj_to_t);
+    let t = mono(__name__.unwrap_or(Str::ever("<Lambda>")));
+    Ok(ValueObj::gen_t(TypeKind::Trait, t, require, impls, None))
+}
+
+/// Super: Type, Impl := Type, Additional := Type -> ClassType
+pub fn subsume_func(mut args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
+    let sup = args.remove_left_or_key("Super").ok_or_else(|| {
+        ErrorCore::new(
+            line!() as usize,
+            ErrorKind::KeyError,
+            Location::Unknown,
+            AtomicStr::from(format!("{RED}Super{RESET} is not passed")),
+            None,
+        )
+    })?;
+    let sup = value_obj_to_t(sup);
+    let impls = args.remove_left_or_key("Impl");
+    let impls = impls.map(value_obj_to_t);
+    let additional = args.remove_left_or_key("Additional");
+    let additional = additional.map(value_obj_to_t);
+    let t = mono(__name__.unwrap_or(Str::ever("<Lambda>")));
+    Ok(ValueObj::gen_t(
+        TypeKind::Subtrait,
+        t,
+        sup,
+        impls,
+        additional,
+    ))
+}

compiler/erg_compiler/context/initialize/mod.rs

@@ -17,7 +17,7 @@ use Type::*;
 
 use erg_parser::ast::VarName;
 
-use crate::context::initialize::const_func::{class_func, inherit_func, inheritable_func};
+use crate::context::initialize::const_func::*;
 use crate::context::instantiate::{ConstTemplate, TyVarContext};
 use crate::context::{ClassDefType, Context, ContextKind, DefaultInfo, ParamSpec, TraitInstance};
 use crate::varinfo::{Mutability, VarInfo, VarKind};
@@ -1496,6 +1496,22 @@ impl Context {
         );
         let inherit = ConstSubr::Builtin(BuiltinConstSubr::new("Inherit", inherit_func, inherit_t));
         self.register_builtin_const("Inherit", ValueObj::Subr(inherit));
+        let trait_t = func(
+            vec![param_t("Requirement", Type)],
+            None,
+            vec![param_t("Impl", Type)],
+            Trait,
+        );
+        let trait_ = ConstSubr::Builtin(BuiltinConstSubr::new("Trait", trait_func, trait_t));
+        self.register_builtin_const("Trait", ValueObj::Subr(trait_));
+        let subsume_t = func(
+            vec![param_t("Super", Trait)],
+            None,
+            vec![param_t("Impl", Type), param_t("Additional", Type)],
+            Trait,
+        );
+        let subsume = ConstSubr::Builtin(BuiltinConstSubr::new("Subsume", subsume_func, subsume_t));
+        self.register_builtin_const("Subsume", ValueObj::Subr(subsume));
         // decorators
         let inheritable_t = func1(Class, Class);
         let inheritable = ConstSubr::Builtin(BuiltinConstSubr::new(

compiler/erg_type/lib.rs

@@ -26,8 +26,8 @@ use crate::free::{
 };
 use crate::typaram::{IntervalOp, TyParam};
 use crate::value::value_set::*;
-use crate::value::ValueObj;
 use crate::value::ValueObj::{Inf, NegInf};
+use crate::value::{EvalValueResult, ValueObj};
 
 /// cloneのコストがあるためなるべく.ref_tを使うようにすること
 /// いくつかの構造体は直接Typeを保持していないので、その場合は.tを使う
@@ -157,7 +157,7 @@ impl ValueArgs {
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct BuiltinConstSubr {
     name: &'static str,
-    subr: fn(ValueArgs, Option<Str>) -> ValueObj,
+    subr: fn(ValueArgs, Option<Str>) -> EvalValueResult<ValueObj>,
     t: Type,
 }
 
@@ -170,7 +170,7 @@ impl fmt::Display for BuiltinConstSubr {
 impl BuiltinConstSubr {
     pub const fn new(
         name: &'static str,
-        subr: fn(ValueArgs, Option<Str>) -> ValueObj,
+        subr: fn(ValueArgs, Option<Str>) -> EvalValueResult<ValueObj>,
         t: Type,
     ) -> Self {
         Self { name, subr, t }
@@ -195,7 +195,7 @@ impl fmt::Display for ConstSubr {
 }
 
 impl ConstSubr {
-    pub fn call(&self, args: ValueArgs, __name__: Option<Str>) -> ValueObj {
+    pub fn call(&self, args: ValueArgs, __name__: Option<Str>) -> EvalValueResult<ValueObj> {
         match self {
             ConstSubr::User(_user) => todo!(),
             ConstSubr::Builtin(builtin) => (builtin.subr)(args, __name__),

compiler/erg_type/value.rs

@@ -9,6 +9,7 @@ use std::ops::Neg;
 use std::rc::Rc;
 
 use erg_common::dict::Dict;
+use erg_common::error::ErrorCore;
 use erg_common::rccell::RcCell;
 use erg_common::serialize::*;
 use erg_common::set;
@@ -22,6 +23,9 @@ use crate::free::fresh_varname;
 use crate::typaram::TyParam;
 use crate::{ConstSubr, HasType, Predicate, Type};
 
+pub type EvalValueError = ErrorCore;
+pub type EvalValueResult<T> = Result<T, EvalValueError>;
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum TypeKind {
     Class,