introduce SELECT capability and skeleton test

[dbsrgits/Data-Query.git] / t / expr.include

use strictures 1;
use Data::Query::ExprBuilder::Identifier;
use Data::Query::Constants qw(DQ_SELECT);
use Data::Query::ExprHelpers qw(perl_scalar_value identifier);

sub expr (&) {
  _mk_expr($_[0]);
}

sub _mk_expr {
  local $_ = Data::Query::ExprBuilder::Identifier->new({
    expr => identifier()
  });
  $_[0]->()->{expr};
}

sub AS {
  my $as = shift;
  (bless(\$as, 'LIES::AS'), @_);
}

sub SELECT (&;@) {
  my @select = map +(
    ref()
      ? $_
      : { expr => perl_scalar_value($_) }
  ), do {
    local $_ = Data::Query::ExprBuilder::Identifier->new({
      expr => identifier()
    });
    $_[0]->();
  };
  my @final;
  while (@select) {
    my $e = shift @select;
    my $res = push @final, +{ expr => $e->{expr} };
    if (ref($select[0]) eq 'LIES::AS') {
      $res->{name} = identifier(shift @select);
    }
  }
      
  return +{
    expr => {
      type => DQ_SELECT,
      select => \@final
    },
  };
}

1;