Add stream.er

compiler/erg_compiler/hir.rs

@@ -1081,9 +1081,14 @@ pub struct Call {
 
 impl NestedDisplay for Call {
     fn fmt_nest(&self, f: &mut std::fmt::Formatter<'_>, level: usize) -> std::fmt::Result {
-        writeln!(f, "({}){}:", self.obj, fmt_option!(self.attr_name),)?;
+        writeln!(f, "({}){}", self.obj, fmt_option!(self.attr_name),)?;
+        if self.args.is_empty() {
+            write!(f, "()")
+        } else {
+            writeln!(f, ":")?;
             self.args.fmt_nest(f, level + 1)
         }
+    }
 }
 
 impl_display_from_nested!(Call);

compiler/erg_parser/ast.rs

@@ -1017,9 +1017,13 @@ impl NestedDisplay for Call {
         if let Some(attr_name) = self.attr_name.as_ref() {
             write!(f, "{}", attr_name)?;
         }
+        if self.args.is_empty() {
+            write!(f, "()")
+        } else {
             writeln!(f, ":")?;
             self.args.fmt_nest(f, level + 1)
         }
+    }
 }
 
 impl_display_from_nested!(Call);

compiler/erg_parser/parse.rs

@@ -2173,11 +2173,14 @@ impl Parser {
         self.skip(); // |>
 
         fn get_stream_op_syntax_error(loc: Location) -> ParseError {
-            ParseError::syntax_error(0, loc, switch_lang!(
+            ParseError::syntax_error(
+                0,
+                loc,
+                switch_lang!(
                     "japanese" => "パイプ演算子の後には関数・メソッド・サブルーチン呼び出しのみが使用できます。",
                     "english" => "Only a call of function, method or subroutine is available after stream operator.",
                 ),
-            None
+                None,
             )
         }
 

compiler/erg_parser/tests/stream.er

@@ -0,0 +1,2 @@
+print!(1 + 1 |> f())
+print!(1 + 1 |> .abs())