[Dbix-class] SQL::Abstract -nest modifier

[Peter Rabbitson]

Hi everyone,

With SQLA 2.0 coming closer to reality, there was a substantial effort
to clear up and disambiguate the SQLA 1.x API. One of the remaining
quirks is the -nest operator, which was introduced in version 1.18.
The examples provided in the documentation make no sense from a
usability point of view, as all of them are more clearly expressed
by other means. Consider (lifted from POD of 1.55)

my %where = (
  user => 'nwiger',
  -nest => [ workhrs => {'>', 20}, geo => 'ASIA' ],
);

VS

my %where = (
  user => 'nwiger',
  -or => [ workhrs => {'>', 20}, geo => 'ASIA'],
);



and

my @where = (
  -and => [
    user => 'nwiger',
    -nest => [
      -and => [workhrs => {'>', 20}, geo => 'ASIA' ],
      -and => [workhrs => {'<', 50}, geo => 'EURO' ]
    ],
  ],
);

VS

my @where = (
  -and => [
    { user => 'nwiger' },
    [
      -and => [workhrs => {'>', 20}, geo => 'ASIA' ],
      -and => [workhrs => {'<', 50}, geo => 'EURO' ]
    ],
  ],
);

The development team of SQLA 2.0 would like to know if there are
real-world -nest usages which can not be easily expressed in any
other ways. If this is not the case, -nest will be marked as
deprecated by a warning starting with the next SQLA version, and
will be completely removed in 2.0.

Any input/thoughts welcome!