Math::Complex: support bare i in the imaginary part

'2+i' should parse as '2+1i'.

Fixes #22711.

Author: mauke

dist/Math-Complex/lib/Math/Complex.pm

@@ -204,6 +204,8 @@ sub _make {
 	($p, $q) = ($1, 0);
     } elsif ($arg =~ /^(?:$gre)?$gre\s*i\s*$/) {
 	($p, $q) = ($1 || 0, $2);
+    } elsif ($arg =~ /^(?:$gre)?\s*([+\-]?)i\s*$/) {
+        ($p, $q) = ($1 || 0, $2 . '1');
     } elsif ($arg =~ /^\s*\($gre\s*(?:,$gre\s*)?\)\s*$/) {
 	($p, $q) = ($1, $2 || 0);
     }

dist/Math-Complex/t/Complex.t

@@ -347,6 +347,22 @@ EOS
     print "ok $test\n";
 EOS
 
+    $test++;
+    push @script, <<EOS;
+    print "# remake 2+i\n";
+    \$z = cplx('2+i');
+    print "not " unless \$z == Math::Complex->make(2,1);
+    print "ok $test\n";
+EOS
+
+    $test++;
+    push @script, <<EOS;
+    print "# make 3-i\n";
+    \$z = Math::Complex->make('3-i');
+    print "not " unless \$z == cplx(3,-1);
+    print "ok $test\n";
+EOS
+
     $test++;
     push @script, <<EOS;
     print "# emake [2,3]\n";