correctly detect unspecified initial H

diff --git a/layout/slopecalc b/layout/slopecalc
index 2c113e9a33c2ed6d83f15efcad6a6d99a4a21e27..4fb11455f6d5ad038f559fdc6b4fb139a12448be 100755 (executable)
--- a/layout/slopecalc
+++ b/layout/slopecalc
@@ -100,7 +100,7 @@ sub complete_current_point ($) {
     my $say_why= 0;
 
     my $this= $cp[$#cp];
-    my $last= $cp[$#cp-1];
+    my $last= @cp > 1 ? $cp[$#cp-1] : undef;
     foreach my $k2 (qw(S L H)) {
        if (defined $last) {
            no strict 'refs';
@@ -136,8 +136,11 @@ sub arg_item ($$) {
     push @cp, $this;
 }
 
+#use Data::Dumper;
+
 sub parse_args () {
     foreach $_ (@ARGV) {
+#print STDERR ">$_<\n", Dumper(\@cp);
        if (m/^\=([-+]?$numre)$/o) {
            arg_item(H, $1);
        } elsif (m/^([-+]?$numre)\%$/o) {