added --equation-above and --equation-below

bin/feedgnuplot

@@ -99,6 +99,8 @@ sub interpretCommandline
   $options{set}        = [];
   $options{unset}      = [];
   $options{equation}   = [];
+  $options{'equation-below'} = [];
+  $options{'equation-above'} = [];
 
   $options{curvestyleall} = '';
   $options{styleall}      = '';
@@ -120,7 +122,7 @@ sub interpretCommandline
              'style=s{2}', 'curvestyle=s{2}', 'curvestyleall=s', 'styleall=s', 'with=s', 'extracmds=s@', 'set=s@', 'unset=s@',
              'every=s{2}', 'everyall=s',
              'square!', 'square_xy!', 'square-xy!', 'squarexy!', 'hardcopy=s', 'maxcurves=i', 'monotonic!', 'timefmt=s',
-             'equation=s@',
+             'equation=s@', 'equation-below=s@', 'equation-above=s@',
              'image=s',
              'histogram=s@', 'binwidth=f', 'histstyle=s',
              'terminal=s',
@@ -503,6 +505,10 @@ sub interpretCommandline
       unshift @{$options{equation}}, qq{"$options{image}" binary filetype=auto flipy with rgbimage title "$options{image}"};
       delete $options{image};
   }
+
+  # --equation-below is a synonym of --equation
+  push @{$options{equation}}, @{$options{'equation-below'}};
+  @{$options{'equation-below'}} = [];
 }
 
 sub getGnuplotVersion
@@ -1156,7 +1162,8 @@ sub plotStoredData
   my @extraopts = map {$_->{options}} @nonemptyCurves;
 
   my $body = join('', map { "$_," } @{$options{equation}});
-  $body .= join(', ' , map({ "'-' $_" } @extraopts) );
+  $body   .= join(', ' , map({ "'-' $_" } @extraopts) );
+  $body   .= join('', map { ",$_" } @{$options{'equation-above'}});
 
   if($options{'3d'}) { print PIPE "splot $body\n"; }
   else               { print PIPE  "plot $body\n"; }
@@ -2079,6 +2086,8 @@ the y-axis extents are not specified (C<--ymin>, C<--ymax>, C<--set 'yrange
 properly. Since this option is just a passthrough to gnuplot, finer control can
 be achieved by passing in C<--equation> and C<--set yrange ...> directly.
 
+=item
+
 C<--equation xxx>
 
 Gnuplot can plot both data and symbolic equations. C<feedgnuplot> generally
@@ -2107,6 +2116,18 @@ points, and I I<also> plot a true circle as a parametric equation.
 
 =item
 
+C<--equation-below xxx>
+
+Synonym for C<--equation>. These are rendered I<below> all the other data.
+
+=item
+
+C<--equation-above xxx>
+
+Like C<--equation>, but is rendered I<on top> of all the other data.
+
+=item
+
 C<--square>
 
 Plot data with aspect ratio 1. For 3D plots, this controls the aspect ratio for