[SOLVED] Perl grep syntax

Issue

I have an HTML and TEXT Mime message. I would like to delete the HTML part. It looks like this will do the trick:

From MIME::Entity:

### Delete some parts of a multipart message:
my @keep = grep { keep_part($_) } $msg->parts;
$msg->parts(\@keep);

But, I'm not sure how to read this, or really what to call it (callback?).. I can locate the part as follows:

  for my $part ($msg->parts()) {
    if ($part->mime_type eq 'text/html') {

Solution

When you supply an ARRAYREF of MIME::Entitys to the parts function, it sets the object to contain exactly those MIME::Entitys. All previous entities are dropped.

The @keep array in the example contains those MIME::Entitys that for which the keep_part returned true and $msg->parts(\@keep); is what sets the new MIME::Entitys in $msg.

The implementation of keep_part could therefore be something like this:

sub keep_part {
    shift->mime_type ne 'text/html';
}

That is, it'll return true if the mime type for the supplied argument is not text/html.

If the condition isn't more complex than that, you may want to just filter it inline instead:

# create an ARRAYREF to the parts to keep and set the parts in $msg:
$msg->parts([ grep { $_->mime_type ne 'text/html' } $msg->parts]);

---

After the filtering has been done, you do not need to check if ($part->mime_type eq 'text/html') in your loop anymore. All text/html MIME entities will have been removed:

for my $part ($msg->parts) {
    print $part->mime_type . "\n";  # no text/html
}

Answered By - Ted Lyngmo

Answer Checked By - Robin (WPSolving Admin)