Question

Normally I just use TStringList.CommaText, but this wont work when a given field has multiple lines. Basically I need a csv processor that conforms to rfc4180. I’d rather not have to implement the RFC myself.

Answer 1

Do you really need full RFC support? I can’t count the number of times I’ve written a “csv parser” in perl or something similar. Split on comma’s and be done. The only problem comes when you need to respect quotes. If you do, write a “quotesplit” routine that looks for quotes and ensures they’re balanced. Unless this csv processor is the meat and potatoes of some application, I’m not sure it’ll really be a problem.

On the other hand, I really don’t think fully implementing the rfc is that complex. That’s a relatively short rfc in comparison to things like… HTTP, SMTP, IMAP, …

In perl, a decent quotesplit() I wrote is:

sub quotesplit {
    my ($regex, $s, $maxsplits) = @_;
    my @split;
    my $quotes = "\"'";
    die("usage: quotesplit(qr/.../,'string...'), // instead of qr//?\n")
        if scalar(@_) < 2;

    my $lastpos;
    while (1) {
        my $pos = pos($s);

        while ($s =~ m/($regex|(?<!\\)[$quotes])/g) {
            if ($1 =~ m/[$quotes]/) {
                $s =~ m/[^$quotes]*/g;
                $s =~ m/(?<!\\)[$quotes]/g;
            }
            else {
                push @split, substr($s,$pos,pos($s) - $pos - length($1));
                last;
            }
        }

        if (defined(pos($s)) and $lastpos > pos($s)) {
            errorf('quotesplit() issue: lastpos %s > pos %s',
                $lastpos, pos($s)
            );
            exit;
        }
        if ((defined($maxsplits) && scalar(@split) == ($maxsplits - 1))) {
            push @split, substr($s,pos($s));
            last;
        }
        elsif (not defined(pos($s))) {
            push @split, substr($s,$lastpos);
            last;
        }

        $lastpos = pos($s);
    }

    return @split;
}