Re-instate old behaviour of List.sum

And also do *NOT* special case [+] anymore. With new-disp, that optimization was probably questionable anyway. Should this show any performance regressions, we can look at that later again, or wait until RakuAST's grammar has landed. This should address #5209 and keep #5205 happy as well.
rakudo · Feb 16, 2023 · 6b6c0ec · 6b6c0ec
1 parent 92d485e
commit 6b6c0ec
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Showing 2 changed files with 27 additions and 33 deletions.
diff --git a/src/core.c/List.pm6 b/src/core.c/List.pm6
@@ -370,24 +370,20 @@ my class List does Iterable does Positional { # declared in BOOTSTRAP
     method to(List:D:)      { self.elems ?? self[self.end].to !! Nil }
     method from(List:D:)    { self.elems ?? self[0].from !! Nil }
 
-    multi method sum(List:D \SELF:) {
+    multi method sum(List:D:) {
         nqp::if(
           self.is-lazy,
           self.fail-iterator-cannot-be-lazy('.sum'),
           nqp::if(
             (my int $elems = self.elems), # reify
-            nqp::if(
-              nqp::iscont(SELF),
-              $elems,
-              nqp::stmts(
-                (my $sum  := 0),
-                (my int $i = -1),
-                nqp::while(
-                  nqp::islt_i(++$i,$elems),
-                  ($sum := $sum + nqp::ifnull(nqp::atpos($!reified,$i),0))
-                ),
-                $sum
-              )
+            nqp::stmts(
+              (my $sum  := 0),
+              (my int $i = -1),
+              nqp::while(
+                nqp::islt_i(++$i,$elems),
+                ($sum := $sum + nqp::ifnull(nqp::atpos($!reified,$i),0))
+              ),
+              $sum
             )
           )
         )

diff --git a/src/core.c/metaops.pm6 b/src/core.c/metaops.pm6
@@ -198,31 +198,29 @@ multi sub METAOP_REDUCE_LEFT(\op) {
         }
     }
     else {
-        nqp::eqaddr(op,&infix:<+>)
-        ?? &sum
-        !! sub (+values) {
-              my $iter := values.iterator;
+        sub (+values) {
+            my $iter := values.iterator;
+            nqp::if(
+              nqp::eqaddr((my $result := $iter.pull-one),IterationEnd),
+              op.(),                         # identity
               nqp::if(
-                nqp::eqaddr((my $result := $iter.pull-one),IterationEnd),
-                op.(),                         # identity
+                nqp::eqaddr((my $value := $iter.pull-one),IterationEnd),
                 nqp::if(
-                  nqp::eqaddr((my $value := $iter.pull-one),IterationEnd),
-                  nqp::if(
-                    nqp::isle_i(op.arity,1),
-                    op.($result),              # can call with 1 param
-                    $result                    # what we got
+                  nqp::isle_i(op.arity,1),
+                  op.($result),              # can call with 1 param
+                  $result                    # what we got
+                ),
+                nqp::stmts(
+                  ($result := op.($result,$value)),
+                  nqp::until(
+                    nqp::eqaddr(($value := $iter.pull-one),IterationEnd),
+                    ($result := op.($result,$value))
                   ),
-                  nqp::stmts(
-                    ($result := op.($result,$value)),
-                    nqp::until(
-                      nqp::eqaddr(($value := $iter.pull-one),IterationEnd),
-                      ($result := op.($result,$value))
-                    ),
-                    $result                    # final result
-                  )
+                  $result                    # final result
                 )
               )
-           }
+            )
+        }
     }
 }