next_sequential.filter

__NAME__ purpose
__END__


__NAME__ see also
__END__


__NAME__ description
__END__


__NAME__ example: Filter example
__END__


* Add new filter, "next_sequential". Allows selection of a next-sequential
value based on a field (and qualified by a field).

[filter op=3D"next_sequential.survey_q.sort"][cgi sort][/filter]

will:

1. Return the existing value if present.
2. If existing value is blank, return max + 1 in the sort field,
	i.e. equivalent to:

	SELECT sort FROM survey_q
	ORDER BY sort DESC
	LIMIT 1

	If another argument of a field name is passed, i.e.

	filter =3D> 'next_sequential.survey_q.sort.sel',

	then you get:

	SELECT sort FROM survey_q
	WHERE sel =3D '[cgi sel]'
	ORDER BY sort DESC
	LIMIT 1

	This allows a next-sequential numbering for things that need it.

	Developed to support general-purpose survey UI for Ton's excellent
	product rating system.