use terminal "dumb" if probing shows "unknown" - fix #66

CHANGES

@@ -1,6 +1,7 @@
 - Split version checking from `use Alien::Gnuplot` line for easier downstream
   packaging. Fixes #98.
 - fixes for Windows (#89)
+- use terminal "dumb" if probing shows "unknown" (#66)
 
 2.024 2023-03-30
 - Add Alien::Gnuplot as a configure-time dependency. Fixes #92 - thanks @zmughal

lib/PDL/Graphics/Gnuplot.pm

@@ -2300,9 +2300,8 @@ sub output {
 
     if(@_) {
 	# Check that, if there is at least one more argument, it is recognizable as a terminal
-	my $terminal;
-	$terminal = lc(shift);
-	$terminal = 'windows' if $^O =~ /mswin32/i and $terminal eq 'unknown';
+	my $terminal = lc(shift);
+	$terminal = 'dumb' if $terminal eq 'unknown';
 	##############################
 	# Check the terminal list here!
 	if(!exists($this->{valid_terms}->{$terminal})) {

t/plot.t

@@ -444,15 +444,15 @@ unlink 'Plot-1.txt' or warn "Can't delete Plot-1.txt after test: $!";
 # accepts both array ref and scalar parameters.
 eval {$w=gpwin('dumb',size=>[7,5]); $w->line(xvals(50)**2); $w->close;};
 is($@, '', "plotting to 42x30 text file worked");
-@lines = eval {open FOO,"<Plot-1.txt"; my @l = <FOO>; close FOO;@l};
+@lines = eval { open my $fh, "<", "Plot-1.txt" or die "Plot-1.txt: $!"; <$fh> };
 is($@, '', "read ASCII plot OK");
 eval { unlink 'Plot-1.txt';};
 
 is(@lines+0, 30, "'7x5 inch' ascii plot created 30 lines (created ".(0+@lines).")");
 
 eval {$w=gpwin('dumb',size=>5); $w->line(xvals(50)**2); $w->close;};
 is($@, '', "plotting to 30x30 text file worked");
-eval {open FOO,"<Plot-1.txt"; @lines = <FOO>; close FOO;};
+@lines = eval { open my $fh, "<", "Plot-1.txt" or die "Plot-1.txt: $!"; <$fh> };
 is($@, '', "Read ASCII plot #2 OK");
 eval { unlink 'Plot-1.txt';};
 
@@ -869,6 +869,7 @@ unlink($testoutput) or warn "\$!: $!";
 ##############################
 # Test default output plotting
 
+unlink qw(Plot-1.txt Plot-2.txt);
  SKIP: {
      if( -e 'Plot-1.txt' || -e 'Plot-2.txt') {
 	 print STDERR "\n***********\nSkipping default-plot-output tests:  files 'Plot-1.txt' and/or 'Plot-2.txt' exist.\n***********\n";