#/usr/bin/perl

Usage: reform [-lNUM] [-rNUM] [-iNUM] [-sNUM] [files]

# Set default values for left margin, right margin, indent
# and paragraph spacing.

$l = 0;
$r = 0;
$i = 0;
$s = 1;

# Process any switches.

while ($ARGV[0] =~ /^-/) {
    $_ = shift;
    /^-(l|r|i|s)(\d+)/ && (eval "\$$1 = \$2", next);
    die "Unrecognized switch: $_\n";
}

# Calculate format strings.

$r = $l + 65 unless $r;
$r -= $l;                       # make $r relative to $l
die "Margins too close\n" if $l + $i >= $r;

$LEFT = ' ' x $l;
$INDENT = ' ' x $i;
$RIGHT1 = '^' . '<' x ($r - 1 - $i);
$RIGHT2 = '^' . '<' x ($r - 1);
$SPACING = "\n" x $s;

# Define a format at run time.

$form = <<"End of Format Definition";
format STDOUT =
$LEFT$INDENT$RIGHT1
\$_
$LEFT$RIGHT2~~
\$_
$SPACING.
End of Format Definition

print $form if $debugging;
eval $form;

# Set paragraph mode on input.

$/ = '';

# For each paragraph...

while (<>) {
    s/\s+/ /g;                      # Canonicalize white space.
    s/ $//;                         # Trim final space.
    s/([a-z0-9][.!?][)'"]*) /$1  /g; # Fix sentence ends.
    write;                          # Spit out new paragraph.
}