#!/usr/bin/perl
=begin metadata
Name: asa
Description: interpret ASA/FORTRAN carriage-controls
Author: Jeffrey S. Haemer
License:
=end metadata
=cut
use strict;
exit 1 if grep {!-r} @ARGV; # traditional
if (grep /-/, @ARGV) {
$0 =~ s(.*/)();
warn "usage: $0 [filename ...]\n";
exit 2; # traditional
}
while (<>) {
chomp;
s/^$/ /;
s/^[^10+-]/\n/;
s/^1/\f/;
s/^\+/\r/;
s/^0/\n\n/;
s/^-/\n\n\n/;
print
or exit 1; # traditional
}
=head1 NAME
asa - interpret ASA/FORTRAN carriage-controls
=head1 SYNOPSIS
asa [I<filename> ...]
=head1 DESCRIPTION
=over 2
Traditional FORTRAN programs put carriage-control characters
in the first columns of their output,
which were interpreted by older lineprinters
according to the ASA vertical format control standard.
(ASA was the American Standards Association -- now ANSI.)
Under this standard, the first character of each printable record (line)
determines vertical spacing, as follows:
=over 2
I<blank> carriage return
0 two carriage returns
1 Formfeed
+ overprint
- three carriage returns (IBM extension)
=back
All other characters are discarded, and empty lines behave as though
they have a leading blank.
B<asa> interprets these characters.
=back
=head1 EXIT VALUES
=over 2
0 normal exit
1 inability to write on stdout or to read an input file
2 bad argument
Exit status values chosen from MKS toolkit.
=back
=head1 AUTHOR
Jeffrey S. Haemer
=head1 BUGS
Currently, B<asa> just looks at the readability of its input files
at startup time. It should really do it a file at a time,
but that makes the code look gross.
The carriage-control '-' is an IBM extension.
Perhaps the default should ignore it
and there should be a '-i' option to interpret it.
=head1 SEE ALSO
Communications of the ACM, Vol 7, No. 10, p. 606, October
1964.
NWG/RFC 189, Appendix C
=cut