Data::Dumper - dump booleans as booleans

Use the support for tracking booleans to dump boolean values as !!1 and
!!0.

Author: haarg

dist/Data-Dumper/Dumper.pm

@@ -18,6 +18,7 @@ use 5.008_001;
 require Exporter;
 
 use constant IS_PRE_516_PERL => $] < 5.016;
+use constant SUPPORTS_CORE_BOOLS => defined &builtin::is_bool;
 
 use Carp ();
 
@@ -551,6 +552,12 @@ sub _dump {
     elsif (!defined($val)) {
       $out .= "undef";
     }
+    elsif (SUPPORTS_CORE_BOOLS && do {
+      BEGIN { SUPPORTS_CORE_BOOLS and warnings->unimport("experimental::builtin") }
+      builtin::is_bool($val)
+    }) {
+      $out .= $val ? '!!1' : '!!0';
+    }
     # This calls the XSUB _vstring (if the XS code is loaded). I'm not *sure* if
     # if belongs in the "Pure Perl" implementation. It sort of depends on what
     # was meant by "Pure Perl", as this subroutine already relies Scalar::Util

dist/Data-Dumper/Dumper.xs

@@ -1279,6 +1279,17 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
 	    }
 	}
 
+#ifdef SvIsBOOL
+	if (SvIsBOOL(val)) {
+		if (SvTRUE(val)) {
+			sv_catpvs(retval, "!!1");
+		}
+		else {
+			sv_catpvs(retval, "!!0");
+		}
+	}
+    else
+#endif
         if (DD_is_integer(val)) {
             STRLEN len;
 	    if (SvIsUV(val))

dist/Data-Dumper/t/dumper.t

@@ -1522,6 +1522,26 @@ EOT
             $want);
 }
 
+#############
+{
+  if (!Data::Dumper::SUPPORTS_CORE_BOOLS) {
+      SKIP_BOTH("Core booleans not supported on older perls");
+      last;
+  }
+  my $want = <<'EOT';
+#$VAR1 = [
+#  !!1,
+#  !!0
+#];
+EOT
+
+  $foo = [ !!1, !!0 ];
+  TEST_BOTH(q(Data::Dumper::DumperX($foo)),
+            'Booleans',
+            $want);
+}
+
+
 #############
 {
   # If XS cannot load, the pure-Perl version cannot deparse vstrings with