## Usage: extract-usage Rdfile

use R::Rdtools;

my $OSdir = "windows";

open INFILE, "< $ARGV[0]" || die "Can't open input file";
open OUTFILE, "> $ARGV[1]" || die "Can't open output file";

while (<INFILE>) {
    chomp;
    open RDFILE, "< $_";
    print OUTFILE "# usages in file $_\n";
    my $text;
    my $skipping = 0;
    while(<RDFILE>) {
	if (/^#ifdef\s+([A-Za-z0-9]+)/o) {
	    if ($1 ne $OSdir) { $skipping = 1; }
	    next;
	}
	if (/^#ifndef\s+([A-Za-z0-9]+)/o) {
	    if ($1 eq $OSdir) { $skipping = 1; }
	    next;
	}
	if (/^#endif/o) {
	    $skipping = 0;
	    next;
	}
	next if $skipping > 0;
	$text .= $_;
    }

    {
	local $/; # unset for get_usages
	%usages = get_usages($text);
    }
    
    foreach $key (keys(%usages)){
	$usages{$key} =~ s/ *\\.?dots/ .../g;
	if ($key !~ /^</) {
	    print OUTFILE "$key <- function$usages{$key} NULL\n";
	}
    }
    
    print OUTFILE "\n";
}