[GENERAL]

[Robert Deme]

Hello!!

in flagship ( a variant of clipper for unix , http://www.wgs.com/) it is
an interesting statement "seek eval" ; it scans the index and for every
position it evaluates a block of code/ function until the function
return true . 
is in postgresql an internal mechanism or a way to use the index when
selecting records with conditions like function(index_expression) =
value ? 
Thanks!