Add ast::Dummy

compiler/erg_compiler/hir.rs

@@ -1476,6 +1476,61 @@ impl Locational for Block {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct Dummy(Vec<Expr>);
+
+impl HasType for Dummy {
+    #[inline]
+    fn ref_t(&self) -> &Type {
+        Type::FAILURE
+    }
+    #[inline]
+    fn ref_mut_t(&mut self) -> &mut Type {
+        todo!()
+    }
+    #[inline]
+    fn t(&self) -> Type {
+        Type::Failure
+    }
+    #[inline]
+    fn signature_t(&self) -> Option<&Type> {
+        Some(Type::FAILURE)
+    }
+    #[inline]
+    fn signature_mut_t(&mut self) -> Option<&mut Type> {
+        todo!()
+    }
+}
+
+impl NestedDisplay for Dummy {
+    fn fmt_nest(&self, f: &mut fmt::Formatter<'_>, level: usize) -> fmt::Result {
+        fmt_lines(self.0.iter(), f, level)
+    }
+}
+
+impl NoTypeDisplay for Dummy {
+    fn to_string_notype(&self) -> String {
+        self.0
+            .iter()
+            .map(|e| e.to_string_notype())
+            .collect::<Vec<_>>()
+            .join("; ")
+    }
+}
+
+impl_display_from_nested!(Dummy);
+impl_stream_for_wrapper!(Dummy, Expr);
+
+impl Locational for Dummy {
+    fn loc(&self) -> Location {
+        if self.0.is_empty() {
+            Location::Unknown
+        } else {
+            Location::concat(self.0.first().unwrap(), self.0.last().unwrap())
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct VarSignature {
     pub ident: Identifier,
@@ -2231,7 +2286,7 @@ pub enum Expr {
     Code(Block),     // code object
     Compound(Block), // compound statement
     Import(Accessor),
-    Dummy(Block), // for mapping to Python AST
+    Dummy(Dummy), // for mapping to Python AST
 }
 
 impl_nested_display_for_chunk_enum!(Expr; Lit, Accessor, Array, Tuple, Dict, Record, BinOp, UnaryOp, Call, Lambda, Def, ClassDef, PatchDef, AttrDef, Code, Compound, TypeAsc, Set, Import, Dummy);

compiler/erg_compiler/lower.rs

@@ -1771,7 +1771,7 @@ impl ASTLowerer {
             ast::Expr::AttrDef(adef) => Ok(hir::Expr::AttrDef(self.lower_attr_def(adef)?)),
             ast::Expr::TypeAsc(tasc) => Ok(hir::Expr::TypeAsc(self.lower_type_asc(tasc)?)),
             // Checking is also performed for expressions in Dummy. However, it has no meaning in code generation
-            ast::Expr::Dummy(dummy) => Ok(hir::Expr::Dummy(self.lower_block(dummy)?)),
+            ast::Expr::Dummy(dummy) => Ok(hir::Expr::Dummy(self.lower_dummy(dummy)?)),
             other => todo!("{other}"),
         }
     }
@@ -1786,6 +1786,16 @@ impl ASTLowerer {
         Ok(hir::Block::new(hir_block))
     }
 
+    fn lower_dummy(&mut self, ast_dummy: ast::Dummy) -> LowerResult<hir::Dummy> {
+        log!(info "entered {}", fn_name!());
+        let mut hir_dummy = Vec::with_capacity(ast_dummy.len());
+        for chunk in ast_dummy.into_iter() {
+            let chunk = self.lower_expr(chunk)?;
+            hir_dummy.push(chunk);
+        }
+        Ok(hir::Dummy::new(hir_dummy))
+    }
+
     fn declare_or_import_var(
         &mut self,
         sig: ast::VarSignature,

compiler/erg_parser/ast.rs

@@ -1166,6 +1166,29 @@ impl Locational for Block {
 
 impl_stream_for_wrapper!(Block, Expr);
 
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Dummy(Vec<Expr>);
+
+impl NestedDisplay for Dummy {
+    fn fmt_nest(&self, f: &mut fmt::Formatter<'_>, level: usize) -> fmt::Result {
+        fmt_lines(self.0.iter(), f, level)
+    }
+}
+
+impl_display_from_nested!(Dummy);
+
+impl Locational for Dummy {
+    fn loc(&self) -> Location {
+        if self.0.is_empty() {
+            Location::Unknown
+        } else {
+            Location::concat(self.0.first().unwrap(), self.0.last().unwrap())
+        }
+    }
+}
+
+impl_stream_for_wrapper!(Dummy, Expr);
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct ConstLocal {
     pub symbol: Token,
@@ -3532,7 +3555,7 @@ pub enum Expr {
     PatchDef(PatchDef),
     AttrDef(AttrDef),
     /// for mapping to Python AST
-    Dummy(Block),
+    Dummy(Dummy),
 }
 
 impl_nested_display_for_chunk_enum!(Expr; Lit, Accessor, Array, Tuple, Dict, Set, Record, BinOp, UnaryOp, Call, DataPack, Lambda, TypeAsc, Def, Methods, ClassDef, PatchDef, AttrDef, Dummy);

compiler/erg_parser/desugar.rs

@@ -14,9 +14,9 @@ use erg_common::{enum_unwrap, get_hash, log, set};
 use crate::ast::{
     Accessor, Args, Array, ArrayComprehension, ArrayTypeSpec, ArrayWithLength, AttrDef, BinOp,
     Block, Call, ClassAttr, ClassAttrs, ClassDef, ConstExpr, DataPack, Def, DefBody, DefId, Dict,
-    Expr, Identifier, KeyValue, KwArg, Lambda, LambdaSignature, Literal, Methods, MixedRecord,
-    Module, NonDefaultParamSignature, NormalArray, NormalDict, NormalRecord, NormalSet,
-    NormalTuple, ParamPattern, ParamRecordAttr, Params, PatchDef, PosArg, Record,
+    Dummy, Expr, Identifier, KeyValue, KwArg, Lambda, LambdaSignature, Literal, Methods,
+    MixedRecord, Module, NonDefaultParamSignature, NormalArray, NormalDict, NormalRecord,
+    NormalSet, NormalTuple, ParamPattern, ParamRecordAttr, Params, PatchDef, PosArg, Record,
     RecordAttrOrIdent, RecordAttrs, Set as astSet, SetWithLength, Signature, SubrSignature, Tuple,
     TupleTypeSpec, TypeAppArgs, TypeBoundSpecs, TypeSpec, TypeSpecWithOp, UnaryOp, VarName,
     VarPattern, VarRecordAttr, VarSignature,
@@ -301,7 +301,7 @@ impl Desugarer {
                 for chunk in exprs.into_iter() {
                     chunks.push(desugar(chunk));
                 }
-                Expr::Dummy(Block::new(chunks))
+                Expr::Dummy(Dummy::new(chunks))
             }
         }
     }