Add Space-invader operator C< -+- >

lib/perlsecret.pod

@@ -19,6 +19,7 @@ Perl secret operators:
     ~-           Inchworm on a stick          high-precedence decrement
     -~           Inchworm on a stick          high-precedence increment
     -+-          Space station                high-precedence numification
+    -=-          Space-invader                add to
     =( )=        Goatse                       scalar / list context
     =< >=~       Flaming X-Wing               match input, assign captures
     ~~<>         Kite                         a single line of input
@@ -452,6 +453,18 @@ or I<strings that do not start with a number>:
 In the above example, C<-+- '-2B'> produces the string C<'-2B'>,
 whereas C<0+ '-2B'> would have given the expected number (C<-2>).
 
+=head2 Space-invader
+
+    -=-
+
+L<Stolen|https://twitter.com/raymondh/status/1131103570856632321> from Python
+by Brian Greenfield, 2019.
+
+An alternative spelling of C< += >.
+
+    $n = 5;
+    $n -=- 3;
+    say $n; # 8
 
 =head2 Goatse
 
@@ -1112,4 +1125,3 @@ This documentation is free; you can redistribute it and/or modify it
 under the same terms as Perl itself.
 
 =cut
-

t/secret.t

@@ -170,6 +170,13 @@ use warnings;
 is( -+- 'two cents', '+two cents',    '-+- exception' );
 is( -+- '-2B' x 5, '-2B-2B-2B-2B-2B', '-+- exception' );
 
+# space-invader
+my $n5 = -2;
+$n5 -=- 0;
+is( $n5, -2, '-=-' );
+$n5 -=- 3;
+is( $n5, 1, '-=-' );
+
 # goatse
 my $n;
 $_ = "word2 and word3";