[groff] 01/01: grog.pl: error messages for a document's first line

[Bernd Warken]

bwarken pushed a commit to branch master
in repository groff.

commit 6f0d81ccdb32432f2d0157ad2788c06c76260e8c
Author: Bernd Warken <address@hidden>
Date:   Wed May 28 13:51:52 2014 +0200

    grog.pl: error messages for a document's first line
---
 src/roff/grog/grog.pl |   45 ++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/src/roff/grog/grog.pl b/src/roff/grog/grog.pl
index bbecbcb..23d6fdd 100644
--- a/src/roff/grog/grog.pl
+++ b/src/roff/grog/grog.pl
@@ -28,7 +28,7 @@
 # <http://www.gnu.org/licenses/gpl-2.0.html>.
 
 ########################################################################
-my $Last_Update = '26 May 2014';
+my $Last_Update = '28 May 2014';
 ########################################################################
 
 require v5.6;
@@ -159,15 +159,46 @@ sub process {
   while (<FILE>) {
     chomp;
 
-    s/^[']/./;
-
     if ( $first_line ) {
-      # when first line, test on comment with character set for grog args
+      # As documented for the `man' program, the first line can be
+      # used as an groff option line.  This is done by:
+      # - start the line with '\" (apostrophe, backslash, double quote)
+      # - add a space character
+      # - a word using the following characters can be appended: `egGjpRst'.
+      #     Each of these characters means an option for the generated
+      #     `groff' command line, e.g. `-t'.
+
+      $first_line = 0; # for later necessary end of first line
+
+      if ( /^\.\\"/ ) {
+       my $line = $_;
+       $line =~ s/^[.]\\"//g;
+       $line =~ s/\s//g;
+       if ( $line =~ /[egGjpRst]+$/ ) {
+         # line is a groff options line with . instead of '
+         print STDERR "First line must start with " .
+           "apostrophe ' instead of period . for groff options line!";
+         s/^\./'/; # line now starts with apostrophe '
+       } else {
+         # line has non-option characters, so is a comment, i.e. ignore
+         next;
+       }
+      }
 
-      $first_line = 0; # end of first line
+      if ( /^'\\"/ ) {
+       s/^'\\"//;
+       s/\W//g;
+       {
+         my $chars = $_;
+         $chars =~ s/[egGjpRst]//g;
+         if ( $chars ) {
+           print STDERR 'Wrong characters in first line: ' .
+             $chars . '.';
+           print STDERR
+             "For an options line are only allowed: [egGjpRst].";
+         }
+       }
 
-      if ( /^\.\\"\s*(.+)$/ ) {
-       my $_ = $1;
        if ( /e/ ) {
          $Groff{'eqn'}++;
        }