ex-fig-ref.pl

#! /usr/bin/perl -w

###################################################
#  Generates tabulated cross references           #
#  pointing to all exercises or figures in SICP.  #
#  Usage: ./ex-fig-ref.pl -e > exercises.texi     #
#  or ./ex-fig-ref.pl -f > figures.texi           #
#  (both of which are included by sicp.texi).     #
#                                                 #
#  © 2013 Andres Raba / License: GNU GPL v.3      #
###################################################

use Math::BigFloat;

$columns = 8;		# number of columns in the table
$squeeze = 1.0;	        # decrease first column width 

%ex_per_chap = (	# how many exercises per chapter
	1 => 46,
	2 => 97,
	3 => 82,
	4 => 79,
	5 => 52
);

%fig_per_chap = (	# how many figures per chapter
	1 => 5,
	2 => 26,
	3 => 38,
	4 => 6,
	5 => 18
);

if (defined($ARGV[0]) and $ARGV[0] eq "-e") {
	$reftype = "Exercise";
	%ref_per_chap = %ex_per_chap;

} elsif (defined($ARGV[0]) and $ARGV[0] eq "-f") {
	$reftype = "Figure";
	%ref_per_chap = %fig_per_chap;

} else {
	print "Choose '-e' for list of exercises or '-f' for list of figures.\n";
}

foreach $chap_no (sort keys(%ref_per_chap)) {

	print "\@subsubheading Chapter $chap_no \n\n";
	print "\@multitable \@columnfractions ";

	$frac = Math::BigFloat->new(1.0 / $columns);
	# each column as a fraction of page width

	$roundfrac = $frac->fround(2);		
	# is there a simpler way to round?

	print $squeeze * $roundfrac, " ";
	for ($i = 2; $i <= $columns; $i++) {
		print "$roundfrac ";
	}
	print "\n";

	for ($ref_no = 1; $ref_no <= $ref_per_chap{$chap_no}; $ref_no++) {

		if (($ref_no == 1) || ((($ref_no - 1) % $columns) == 0)) {
			print "\@item \n";
		}

		print "\@ref{$reftype $chap_no.$ref_no,,$chap_no.$ref_no}";

		if (($ref_no % $columns) != 0) {
			print " \@tab \n";
		} else {
			print "\n";
		}
	}

	print "\@end multitable \n\n";
}