File Coverage

blib/lib/SQL/Abstract.pm

Criterion	Covered	Total	%
statement	584	666	87.6
branch	194	254	76.3
condition	100	141	70.9
subroutine	122	140	87.1
pod	10	12	83.3
total	1010	1213	83.2

package SQL::Abstract; # see doc at end of file

use strict;
use warnings;
use Carp ();
use List::Util ();
use Scalar::Util ();

use Exporter 'import';
our @EXPORT_OK = qw(is_plain_value is_literal_value);

BEGIN {
  if ($] < 5.009_005) {
    require MRO::Compat;
  }
  else {
    require mro;
  }

  *SQL::Abstract::_ENV_::DETECT_AUTOGENERATED_STRINGIFICATION = $ENV{SQLA_ISVALUE_IGNORE_AUTOGENERATED_STRINGIFICATION}
    ? sub () { 0 }
    : sub () { 1 }
  ;
}

#======================================================================
# GLOBALS
#======================================================================

our $VERSION  = '1.86';

# This would confuse some packagers
$VERSION = eval $VERSION if $VERSION =~ /_/; # numify for warning-free dev releases

our $AUTOLOAD;

# special operators (-in, -between). May be extended/overridden by user.
# See section WHERE: BUILTIN SPECIAL OPERATORS below for implementation
my @BUILTIN_SPECIAL_OPS = (
  {regex => qr/^ (?: not \s )? between $/ix, handler => '_where_field_BETWEEN'},
  {regex => qr/^ (?: not \s )? in      $/ix, handler => '_where_field_IN'},
  {regex => qr/^ ident                 $/ix, handler => '_where_op_IDENT'},
  {regex => qr/^ value                 $/ix, handler => '_where_op_VALUE'},
  {regex => qr/^ is (?: \s+ not )?     $/ix, handler => '_where_field_IS'},
);

# unaryish operators - key maps to handler
my @BUILTIN_UNARY_OPS = (
  # the digits are backcompat stuff
  { regex => qr/^ and  (?: [_\s]? \d+ )? $/xi, handler => '_where_op_ANDOR' },
  { regex => qr/^ or   (?: [_\s]? \d+ )? $/xi, handler => '_where_op_ANDOR' },
  { regex => qr/^ nest (?: [_\s]? \d+ )? $/xi, handler => '_where_op_NEST' },
  { regex => qr/^ (?: not \s )? bool     $/xi, handler => '_where_op_BOOL' },
  { regex => qr/^ ident                  $/xi, handler => '_where_op_IDENT' },
  { regex => qr/^ value                  $/xi, handler => '_where_op_VALUE' },
);

#======================================================================
# DEBUGGING AND ERROR REPORTING
#======================================================================

sub _debug {
  return unless $_[0]->{debug}; shift; # a little faster
  my $func = (caller(1))[3];
  warn "[$func] ", @_, "\n";
}

sub belch (@) {
  my($func) = (caller(1))[3];
  Carp::carp "[$func] Warning: ", @_;
}

sub puke (@) {
  my($func) = (caller(1))[3];
  Carp::croak "[$func] Fatal: ", @_;
}

sub is_literal_value ($) {
    ref $_[0] eq 'SCALAR'                                     ? [ ${$_[0]} ]
  : ( ref $_[0] eq 'REF' and ref ${$_[0]} eq 'ARRAY' )        ? [ @${ $_[0] } ]
  : undef;
}

# FIXME XSify - this can be done so much more efficiently
sub is_plain_value ($) {
  no strict 'refs';
    ! length ref $_[0]                                        ? \($_[0])
  : (
    ref $_[0] eq 'HASH' and keys %{$_[0]} == 1
      and
    exists $_[0]->{-value}
  )                                                           ? \($_[0]->{-value})
  : (
      # reuse @_ for even moar speedz
      defined ( $_[1] = Scalar::Util::blessed $_[0] )
        and
      # deliberately not using Devel::OverloadInfo - the checks we are
      # intersted in are much more limited than the fullblown thing, and
      # this is a very hot piece of code
      (
        # simply using ->can('(""') can leave behind stub methods that
        # break actually using the overload later (see L
        # found while resolving method "%s" overloading "%s" in package
        # "%s"> and the source of overload::mycan())
        #
        # either has stringification which DBI SHOULD prefer out of the box
        grep { *{ (qq[${_}::(""]) }{CODE} } @{ $_[2] = mro::get_linear_isa( $_[1] ) }
          or
        # has nummification or boolification, AND fallback is *not* disabled
        (
          SQL::Abstract::_ENV_::DETECT_AUTOGENERATED_STRINGIFICATION
            and
          (
            grep { *{"${_}::(0+"}{CODE} } @{$_[2]}
              or
            grep { *{"${_}::(bool"}{CODE} } @{$_[2]}
          )
            and
          (
            # no fallback specified at all
            ! ( ($_[3]) = grep { *{"${_}::()"}{CODE} } @{$_[2]} )
              or
            # fallback explicitly undef
            ! defined ${"$_[3]::()"}
              or
            # explicitly true
            !! ${"$_[3]::()"}
          )
        )
      )
    )                                                          ? \($_[0])
  : undef;
}



#======================================================================
# NEW
#======================================================================

sub new {
  my $self = shift;
  my $class = ref($self) || $self;
  my %opt = (ref $_[0] eq 'HASH') ? %{$_[0]} : @_;

  # choose our case by keeping an option around
  delete $opt{case} if $opt{case} && $opt{case} ne 'lower';

  # default logic for interpreting arrayrefs
  $opt{logic} = $opt{logic} ? uc $opt{logic} : 'OR';

  # how to return bind vars
  $opt{bindtype} ||= 'normal';

  # default comparison is "=", but can be overridden
  $opt{cmp} ||= '=';

  # try to recognize which are the 'equality' and 'inequality' ops
  # (temporary quickfix (in 2007), should go through a more seasoned API)
  $opt{equality_op}   = qr/^( \Q$opt{cmp}\E | \= )$/ix;
  $opt{inequality_op} = qr/^( != | <> )$/ix;

  $opt{like_op}       = qr/^ (is\s+)? r?like $/xi;
  $opt{not_like_op}   = qr/^ (is\s+)? not \s+ r?like $/xi;

  # SQL booleans
  $opt{sqltrue}  ||= '1=1';
  $opt{sqlfalse} ||= '0=1';

  # special operators
  $opt{special_ops} ||= [];
  # regexes are applied in order, thus push after user-defines
  push @{$opt{special_ops}}, @BUILTIN_SPECIAL_OPS;

  # unary operators
  $opt{unary_ops} ||= [];
  push @{$opt{unary_ops}}, @BUILTIN_UNARY_OPS;

  # rudimentary sanity-check for user supplied bits treated as functions/operators
  # If a purported  function matches this regular expression, an exception is thrown.
  # Literal SQL is *NOT* subject to this check, only functions (and column names
  # when quoting is not in effect)

  # FIXME
  # need to guard against ()'s in column names too, but this will break tons of
  # hacks... ideas anyone?
  $opt{injection_guard} ||= qr/
    \;
      |
    ^ \s* go \s
  /xmi;

  return bless \%opt, $class;
}


sub _assert_pass_injection_guard {
  if ($_[1] =~ $_[0]->{injection_guard}) {
    my $class = ref $_[0];
    puke "Possible SQL injection attempt '$_[1]'. If this is indeed a part of the "
     . "desired SQL use literal SQL ( \'...' or \[ '...' ] ) or supply your own "
     . "{injection_guard} attribute to ${class}->new()"
  }
}


#======================================================================
# INSERT methods
#======================================================================

sub insert {
  my $self    = shift;
  my $table   = $self->_table(shift);
  my $data    = shift || return;
  my $options = shift;

  my $method       = $self->_METHOD_FOR_refkind("_insert", $data);
  my ($sql, @bind) = $self->$method($data);
  $sql = join " ", $self->_sqlcase('insert into'), $table, $sql;

  if ($options->{returning}) {
    my ($s, @b) = $self->_insert_returning($options);
    $sql .= $s;
    push @bind, @b;
  }

  return wantarray ? ($sql, @bind) : $sql;
}

# So that subclasses can override INSERT ... RETURNING separately from
# UPDATE and DELETE (e.g. DBIx::Class::SQLMaker::Oracle does this)
sub _insert_returning { shift->_returning(@_) }

sub _returning {
  my ($self, $options) = @_;

  my $f = $options->{returning};

  my $fieldlist = $self->_SWITCH_refkind($f, {
    ARRAYREF     => sub {join ', ', map { $self->_quote($_) } @$f;},
    SCALAR       => sub {$self->_quote($f)},
    SCALARREF    => sub {$$f},
  });
  return $self->_sqlcase(' returning ') . $fieldlist;
}

sub _insert_HASHREF { # explicit list of fields and then values
  my ($self, $data) = @_;

  my @fields = sort keys %$data;

  my ($sql, @bind) = $self->_insert_values($data);

  # assemble SQL
  $_ = $self->_quote($_) foreach @fields;
  $sql = "( ".join(", ", @fields).") ".$sql;

  return ($sql, @bind);
}

sub _insert_ARRAYREF { # just generate values(?,?) part (no list of fields)
  my ($self, $data) = @_;

  # no names (arrayref) so can't generate bindtype
  $self->{bindtype} ne 'columns'
    or belch "can't do 'columns' bindtype when called with arrayref";

  my (@values, @all_bind);
  foreach my $value (@$data) {
    my ($values, @bind) = $self->_insert_value(undef, $value);
    push @values, $values;
    push @all_bind, @bind;
  }
  my $sql = $self->_sqlcase('values')." ( ".join(", ", @values)." )";
  return ($sql, @all_bind);
}

sub _insert_ARRAYREFREF { # literal SQL with bind
  my ($self, $data) = @_;

  my ($sql, @bind) = @${$data};
  $self->_assert_bindval_matches_bindtype(@bind);

  return ($sql, @bind);
}


sub _insert_SCALARREF { # literal SQL without bind
  my ($self, $data) = @_;

  return ($$data);
}

sub _insert_values {
  my ($self, $data) = @_;

  my (@values, @all_bind);
  foreach my $column (sort keys %$data) {
    my ($values, @bind) = $self->_insert_value($column, $data->{$column});
    push @values, $values;
    push @all_bind, @bind;
  }
  my $sql = $self->_sqlcase('values')." ( ".join(", ", @values)." )";
  return ($sql, @all_bind);
}

sub _insert_value {
  my ($self, $column, $v) = @_;

  my (@values, @all_bind);
  $self->_SWITCH_refkind($v, {

    ARRAYREF => sub {
      if ($self->{array_datatypes}) { # if array datatype are activated
        push @values, '?';
        push @all_bind, $self->_bindtype($column, $v);
      }
      else {                  # else literal SQL with bind
        my ($sql, @bind) = @$v;
        $self->_assert_bindval_matches_bindtype(@bind);
        push @values, $sql;
        push @all_bind, @bind;
      }
    },

    ARRAYREFREF => sub {        # literal SQL with bind
      my ($sql, @bind) = @${$v};
      $self->_assert_bindval_matches_bindtype(@bind);
      push @values, $sql;
      push @all_bind, @bind;
    },

    # THINK: anything useful to do with a HASHREF ?
    HASHREF => sub {       # (nothing, but old SQLA passed it through)
      #TODO in SQLA >= 2.0 it will die instead
      belch "HASH ref as bind value in insert is not supported";
      push @values, '?';
      push @all_bind, $self->_bindtype($column, $v);
    },

    SCALARREF => sub {          # literal SQL without bind
      push @values, $$v;
    },

    SCALAR_or_UNDEF => sub {
      push @values, '?';
      push @all_bind, $self->_bindtype($column, $v);
    },

  });

  my $sql = join(", ", @values);
  return ($sql, @all_bind);
}



#======================================================================
# UPDATE methods
#======================================================================


sub update {
  my $self    = shift;
  my $table   = $self->_table(shift);
  my $data    = shift || return;
  my $where   = shift;
  my $options = shift;

  # first build the 'SET' part of the sql statement
  puke "Unsupported data type specified to \$sql->update"
    unless ref $data eq 'HASH';

  my ($sql, @all_bind) = $self->_update_set_values($data);
  $sql = $self->_sqlcase('update ') . $table . $self->_sqlcase(' set ')
          . $sql;

  if ($where) {
    my($where_sql, @where_bind) = $self->where($where);
    $sql .= $where_sql;
    push @all_bind, @where_bind;
  }

  if ($options->{returning}) {
    my ($returning_sql, @returning_bind) = $self->_update_returning($options);
    $sql .= $returning_sql;
    push @all_bind, @returning_bind;
  }

  return wantarray ? ($sql, @all_bind) : $sql;
}

sub _update_set_values {
  my ($self, $data) = @_;

  my (@set, @all_bind);
  for my $k (sort keys %$data) {
    my $v = $data->{$k};
    my $r = ref $v;
    my $label = $self->_quote($k);

    $self->_SWITCH_refkind($v, {
      ARRAYREF => sub {
        if ($self->{array_datatypes}) { # array datatype
          push @set, "$label = ?";
          push @all_bind, $self->_bindtype($k, $v);
        }
        else {                          # literal SQL with bind
          my ($sql, @bind) = @$v;
          $self->_assert_bindval_matches_bindtype(@bind);
          push @set, "$label = $sql";
          push @all_bind, @bind;
        }
      },
      ARRAYREFREF => sub { # literal SQL with bind
        my ($sql, @bind) = @${$v};
        $self->_assert_bindval_matches_bindtype(@bind);
        push @set, "$label = $sql";
        push @all_bind, @bind;
      },
      SCALARREF => sub {  # literal SQL without bind
        push @set, "$label = $$v";
      },
      HASHREF => sub {
        my ($op, $arg, @rest) = %$v;

        puke 'Operator calls in update must be in the form { -op => $arg }'
          if (@rest or not $op =~ /^\-(.+)/);

        local $self->{_nested_func_lhs} = $k;
        my ($sql, @bind) = $self->_where_unary_op($1, $arg);

        push @set, "$label = $sql";
        push @all_bind, @bind;
      },
      SCALAR_or_UNDEF => sub {
        push @set, "$label = ?";
        push @all_bind, $self->_bindtype($k, $v);
      },
    });
  }

  # generate sql
  my $sql = join ', ', @set;

  return ($sql, @all_bind);
}

# So that subclasses can override UPDATE ... RETURNING separately from
# INSERT and DELETE
sub _update_returning { shift->_returning(@_) }



#======================================================================
# SELECT
#======================================================================


sub select {
  my $self   = shift;
  my $table  = $self->_table(shift);
  my $fields = shift || '*';
  my $where  = shift;
  my $order  = shift;

  my ($fields_sql, @bind) = $self->_select_fields($fields);

  my ($where_sql, @where_bind) = $self->where($where, $order);
  push @bind, @where_bind;

  my $sql = join(' ', $self->_sqlcase('select'), $fields_sql,
                      $self->_sqlcase('from'),   $table)
          . $where_sql;

  return wantarray ? ($sql, @bind) : $sql;
}

sub _select_fields {
  my ($self, $fields) = @_;
  return ref $fields eq 'ARRAY' ? join ', ', map { $self->_quote($_) } @$fields
                                : $fields;
}

#======================================================================
# DELETE
#======================================================================


sub delete {
  my $self    = shift;
  my $table   = $self->_table(shift);
  my $where   = shift;
  my $options = shift;

  my($where_sql, @bind) = $self->where($where);
  my $sql = $self->_sqlcase('delete from ') . $table . $where_sql;

  if ($options->{returning}) {
    my ($returning_sql, @returning_bind) = $self->_delete_returning($options);
    $sql .= $returning_sql;
    push @bind, @returning_bind;
  }

  return wantarray ? ($sql, @bind) : $sql;
}

# So that subclasses can override DELETE ... RETURNING separately from
# INSERT and UPDATE
sub _delete_returning { shift->_returning(@_) }



#======================================================================
# WHERE: entry point
#======================================================================



# Finally, a separate routine just to handle WHERE clauses
sub where {
  my ($self, $where, $order) = @_;

  # where ?
  my ($sql, @bind) = $self->_recurse_where($where);
  $sql = (defined $sql and length $sql) ? $self->_sqlcase(' where ') . "( $sql )" : '';

  # order by?
  if ($order) {
    my ($order_sql, @order_bind) = $self->_order_by($order);
    $sql .= $order_sql;
    push @bind, @order_bind;
  }

  return wantarray ? ($sql, @bind) : $sql;
}


sub _recurse_where {
  my ($self, $where, $logic) = @_;

  # dispatch on appropriate method according to refkind of $where
  my $method = $self->_METHOD_FOR_refkind("_where", $where);

  my ($sql, @bind) =  $self->$method($where, $logic);

  # DBIx::Class used to call _recurse_where in scalar context
  # something else might too...
  if (wantarray) {
    return ($sql, @bind);
  }
  else {
    belch "Calling _recurse_where in scalar context is deprecated and will go away before 2.0";
    return $sql;
  }
}



#======================================================================
# WHERE: top-level ARRAYREF
#======================================================================


sub _where_ARRAYREF {
  my ($self, $where, $logic) = @_;

  $logic = uc($logic || $self->{logic});
  $logic eq 'AND' or $logic eq 'OR' or puke "unknown logic: $logic";

  my @clauses = @$where;

  my (@sql_clauses, @all_bind);
  # need to use while() so can shift() for pairs
  while (@clauses) {
    my $el = shift @clauses;

    $el = undef if (defined $el and ! length $el);

    # switch according to kind of $el and get corresponding ($sql, @bind)
    my ($sql, @bind) = $self->_SWITCH_refkind($el, {

      # skip empty elements, otherwise get invalid trailing AND stuff
      ARRAYREF  => sub {$self->_recurse_where($el)        if @$el},

      ARRAYREFREF => sub {
        my ($s, @b) = @$$el;
        $self->_assert_bindval_matches_bindtype(@b);
        ($s, @b);
      },

      HASHREF   => sub {$self->_recurse_where($el, 'and') if %$el},

      SCALARREF => sub { ($$el);                                 },

      SCALAR    => sub {
        # top-level arrayref with scalars, recurse in pairs
        $self->_recurse_where({$el => shift(@clauses)})
      },

      UNDEF     => sub {puke "Supplying an empty left hand side argument is not supported in array-pairs" },
    });

    if ($sql) {
      push @sql_clauses, $sql;
      push @all_bind, @bind;
    }
  }

  return $self->_join_sql_clauses($logic, \@sql_clauses, \@all_bind);
}

#======================================================================
# WHERE: top-level ARRAYREFREF
#======================================================================

sub _where_ARRAYREFREF {
    my ($self, $where) = @_;
    my ($sql, @bind) = @$$where;
    $self->_assert_bindval_matches_bindtype(@bind);
    return ($sql, @bind);
}

#======================================================================
# WHERE: top-level HASHREF
#======================================================================

sub _where_HASHREF {
  my ($self, $where) = @_;
  my (@sql_clauses, @all_bind);

  for my $k (sort keys %$where) {
    my $v = $where->{$k};

    # ($k => $v) is either a special unary op or a regular hashpair
    my ($sql, @bind) = do {
      if ($k =~ /^-./) {
        # put the operator in canonical form
        my $op = $k;
        $op = substr $op, 1;  # remove initial dash
        $op =~ s/^\s+|\s+$//g;# remove leading/trailing space
        $op =~ s/\s+/ /g;     # compress whitespace

        # so that -not_foo works correctly
        $op =~ s/^not_/NOT /i;

        $self->_debug("Unary OP(-$op) within hashref, recursing...");
        my ($s, @b) = $self->_where_unary_op($op, $v);

        # top level vs nested
        # we assume that handled unary ops will take care of their ()s
        $s = "($s)" unless (
          List::Util::first {$op =~ $_->{regex}} @{$self->{unary_ops}}
            or
          ( defined $self->{_nested_func_lhs} and $self->{_nested_func_lhs} eq $k )
        );
        ($s, @b);
      }
      else {
        if (! length $k) {
          if (is_literal_value ($v) ) {
            belch 'Hash-pairs consisting of an empty string with a literal are deprecated, and will be removed in 2.0: use -and => [ $literal ] instead';
          }
          else {
            puke "Supplying an empty left hand side argument is not supported in hash-pairs";
          }
        }

        my $method = $self->_METHOD_FOR_refkind("_where_hashpair", $v);
        $self->$method($k, $v);
      }
    };

    push @sql_clauses, $sql;
    push @all_bind, @bind;
  }

  return $self->_join_sql_clauses('and', \@sql_clauses, \@all_bind);
}

sub _where_unary_op {
  my ($self, $op, $rhs) = @_;

  # top level special ops are illegal in general
  # this includes the -ident/-value ops (dual purpose unary and special)
  puke "Illegal use of top-level '-$op'"
    if ! defined $self->{_nested_func_lhs} and List::Util::first { $op =~ $_->{regex} } @{$self->{special_ops}};

  if (my $op_entry = List::Util::first { $op =~ $_->{regex} } @{$self->{unary_ops}}) {
    my $handler = $op_entry->{handler};

    if (not ref $handler) {
      if ($op =~ s/ [_\s]? \d+ $//x ) {
        belch 'Use of [and|or|nest]_N modifiers is deprecated and will be removed in SQLA v2.0. '
            . "You probably wanted ...-and => [ -$op => COND1, -$op => COND2 ... ]";
      }
      return $self->$handler($op, $rhs);
    }
    elsif (ref $handler eq 'CODE') {
      return $handler->($self, $op, $rhs);
    }
    else {
      puke "Illegal handler for operator $op - expecting a method name or a coderef";
    }
  }

  $self->_debug("Generic unary OP: $op - recursing as function");

  $self->_assert_pass_injection_guard($op);

  my ($sql, @bind) = $self->_SWITCH_refkind($rhs, {
    SCALAR =>   sub {
      puke "Illegal use of top-level '-$op'"
        unless defined $self->{_nested_func_lhs};

      return (
        $self->_convert('?'),
        $self->_bindtype($self->{_nested_func_lhs}, $rhs)
      );
    },
    FALLBACK => sub {
      $self->_recurse_where($rhs)
    },
  });

  $sql = sprintf('%s %s',
    $self->_sqlcase($op),
    $sql,
  );

  return ($sql, @bind);
}

sub _where_op_ANDOR {
  my ($self, $op, $v) = @_;

  $self->_SWITCH_refkind($v, {
    ARRAYREF => sub {
      return $self->_where_ARRAYREF($v, $op);
    },

    HASHREF => sub {
      return ($op =~ /^or/i)
        ? $self->_where_ARRAYREF([ map { $_ => $v->{$_} } (sort keys %$v) ], $op)
        : $self->_where_HASHREF($v);
    },

    SCALARREF  => sub {
      puke "-$op => \\\$scalar makes little sense, use " .
        ($op =~ /^or/i
          ? '[ \$scalar, \%rest_of_conditions ] instead'
          : '-and => [ \$scalar, \%rest_of_conditions ] instead'
        );
    },

    ARRAYREFREF => sub {
      puke "-$op => \\[...] makes little sense, use " .
        ($op =~ /^or/i
          ? '[ \[...], \%rest_of_conditions ] instead'
          : '-and => [ \[...], \%rest_of_conditions ] instead'
        );
    },

    SCALAR => sub { # permissively interpreted as SQL
      puke "-$op => \$value makes little sense, use -bool => \$value instead";
    },

    UNDEF => sub {
      puke "-$op => undef not supported";
    },
   });
}

sub _where_op_NEST {
  my ($self, $op, $v) = @_;

  $self->_SWITCH_refkind($v, {

    SCALAR => sub { # permissively interpreted as SQL
      belch "literal SQL should be -nest => \\'scalar' "
          . "instead of -nest => 'scalar' ";
      return ($v);
    },

    UNDEF => sub {
      puke "-$op => undef not supported";
    },

    FALLBACK => sub {
      $self->_recurse_where($v);
    },

   });
}


sub _where_op_BOOL {
  my ($self, $op, $v) = @_;

  my ($s, @b) = $self->_SWITCH_refkind($v, {
    SCALAR => sub { # interpreted as SQL column
      $self->_convert($self->_quote($v));
    },

    UNDEF => sub {
      puke "-$op => undef not supported";
    },

    FALLBACK => sub {
      $self->_recurse_where($v);
    },
  });

  $s = "(NOT $s)" if $op =~ /^not/i;
  ($s, @b);
}


sub _where_op_IDENT {
  my $self = shift;
  my ($op, $rhs) = splice @_, -2;
  if (! defined $rhs or length ref $rhs) {
    puke "-$op requires a single plain scalar argument (a quotable identifier)";
  }

  # in case we are called as a top level special op (no '=')
  my $lhs = shift;

  $_ = $self->_convert($self->_quote($_)) for ($lhs, $rhs);

  return $lhs
    ? "$lhs = $rhs"
    : $rhs
  ;
}

sub _where_op_VALUE {
  my $self = shift;
  my ($op, $rhs) = splice @_, -2;

  # in case we are called as a top level special op (no '=')
  my $lhs = shift;

  # special-case NULL
  if (! defined $rhs) {
    return defined $lhs
      ? $self->_convert($self->_quote($lhs)) . ' IS NULL'
      : undef
    ;
  }

  my @bind =
    $self->_bindtype(
      (defined $lhs ? $lhs : $self->{_nested_func_lhs}),
      $rhs,
    )
  ;

  return $lhs
    ? (
      $self->_convert($self->_quote($lhs)) . ' = ' . $self->_convert('?'),
      @bind
    )
    : (
      $self->_convert('?'),
      @bind,
    )
  ;
}

sub _where_hashpair_ARRAYREF {
  my ($self, $k, $v) = @_;

  if (@$v) {
    my @v = @$v; # need copy because of shift below
    $self->_debug("ARRAY($k) means distribute over elements");

    # put apart first element if it is an operator (-and, -or)
    my $op = (
       (defined $v[0] && $v[0] =~ /^ - (?: AND|OR ) $/ix)
         ? shift @v
         : ''
    );
    my @distributed = map { {$k =>  $_} } @v;

    if ($op) {
      $self->_debug("OP($op) reinjected into the distributed array");
      unshift @distributed, $op;
    }

    my $logic = $op ? substr($op, 1) : '';

    return $self->_recurse_where(\@distributed, $logic);
  }
  else {
    $self->_debug("empty ARRAY($k) means 0=1");
    return ($self->{sqlfalse});
  }
}

sub _where_hashpair_HASHREF {
  my ($self, $k, $v, $logic) = @_;
  $logic ||= 'and';

  local $self->{_nested_func_lhs} = defined $self->{_nested_func_lhs}
    ? $self->{_nested_func_lhs}
    : $k
  ;

  my ($all_sql, @all_bind);

  for my $orig_op (sort keys %$v) {
    my $val = $v->{$orig_op};

    # put the operator in canonical form
    my $op = $orig_op;

    # FIXME - we need to phase out dash-less ops
    $op =~ s/^-//;        # remove possible initial dash
    $op =~ s/^\s+|\s+$//g;# remove leading/trailing space
    $op =~ s/\s+/ /g;     # compress whitespace

    $self->_assert_pass_injection_guard($op);

    # fixup is_not
    $op =~ s/^is_not/IS NOT/i;

    # so that -not_foo works correctly
    $op =~ s/^not_/NOT /i;

    # another retarded special case: foo => { $op => { -value => undef } }
    if (ref $val eq 'HASH' and keys %$val == 1 and exists $val->{-value} and ! defined $val->{-value} ) {
      $val = undef;
    }

    my ($sql, @bind);

    # CASE: col-value logic modifiers
    if ($orig_op =~ /^ \- (and|or) $/xi) {
      ($sql, @bind) = $self->_where_hashpair_HASHREF($k, $val, $1);
    }
    # CASE: special operators like -in or -between
    elsif (my $special_op = List::Util::first { $op =~ $_->{regex} } @{$self->{special_ops}}) {
      my $handler = $special_op->{handler};
      if (! $handler) {
        puke "No handler supplied for special operator $orig_op";
      }
      elsif (not ref $handler) {
        ($sql, @bind) = $self->$handler($k, $op, $val);
      }
      elsif (ref $handler eq 'CODE') {
        ($sql, @bind) = $handler->($self, $k, $op, $val);
      }
      else {
        puke "Illegal handler for special operator $orig_op - expecting a method name or a coderef";
      }
    }
    else {
      $self->_SWITCH_refkind($val, {

        ARRAYREF => sub {       # CASE: col => {op => \@vals}
          ($sql, @bind) = $self->_where_field_op_ARRAYREF($k, $op, $val);
        },

        ARRAYREFREF => sub {    # CASE: col => {op => \[$sql, @bind]} (literal SQL with bind)
          my ($sub_sql, @sub_bind) = @$$val;
          $self->_assert_bindval_matches_bindtype(@sub_bind);
          $sql  = join ' ', $self->_convert($self->_quote($k)),
                            $self->_sqlcase($op),
                            $sub_sql;
          @bind = @sub_bind;
        },

        UNDEF => sub {          # CASE: col => {op => undef} : sql "IS (NOT)? NULL"
          my $is =
            $op =~ /^not$/i               ? 'is not'  # legacy
          : $op =~ $self->{equality_op}   ? 'is'
          : $op =~ $self->{like_op}       ? belch("Supplying an undefined argument to '@{[ uc $op]}' is deprecated") && 'is'
          : $op =~ $self->{inequality_op} ? 'is not'
          : $op =~ $self->{not_like_op}   ? belch("Supplying an undefined argument to '@{[ uc $op]}' is deprecated") && 'is not'
          : puke "unexpected operator '$orig_op' with undef operand";

          $sql = $self->_quote($k) . $self->_sqlcase(" $is null");
        },

        FALLBACK => sub {       # CASE: col => {op/func => $stuff}
          ($sql, @bind) = $self->_where_unary_op($op, $val);

          $sql = join(' ',
            $self->_convert($self->_quote($k)),
            $self->{_nested_func_lhs} eq $k ? $sql : "($sql)",  # top level vs nested
          );
        },
      });
    }

    ($all_sql) = (defined $all_sql and $all_sql) ? $self->_join_sql_clauses($logic, [$all_sql, $sql], []) : $sql;
    push @all_bind, @bind;
  }
  return ($all_sql, @all_bind);
}

sub _where_field_IS {
  my ($self, $k, $op, $v) = @_;

  my ($s) = $self->_SWITCH_refkind($v, {
    UNDEF => sub {
      join ' ',
        $self->_convert($self->_quote($k)),
        map { $self->_sqlcase($_)} ($op, 'null')
    },
    FALLBACK => sub {
      puke "$op can only take undef as argument";
    },
  });

  $s;
}

sub _where_field_op_ARRAYREF {
  my ($self, $k, $op, $vals) = @_;

  my @vals = @$vals;  #always work on a copy

  if (@vals) {
    $self->_debug(sprintf '%s means multiple elements: [ %s ]',
      $vals,
      join(', ', map { defined $_ ? "'$_'" : 'NULL' } @vals ),
    );

    # see if the first element is an -and/-or op
    my $logic;
    if (defined $vals[0] && $vals[0] =~ /^ - (AND|OR) $/ix) {
      $logic = uc $1;
      shift @vals;
    }

    # a long standing API wart - an attempt to change this behavior during
    # the 1.50 series failed *spectacularly*. Warn instead and leave the
    # behavior as is
    if (
      @vals > 1
        and
      (!$logic or $logic eq 'OR')
        and
      ($op =~ $self->{inequality_op} or $op =~ $self->{not_like_op})
    ) {
      my $o = uc($op);
      belch "A multi-element arrayref as an argument to the inequality op '$o' "
          . 'is technically equivalent to an always-true 1=1 (you probably wanted '
          . "to say ...{ \$inequality_op => [ -and => \@values ] }... instead)"
      ;
    }

    # distribute $op over each remaining member of @vals, append logic if exists
    return $self->_recurse_where([map { {$k => {$op, $_}} } @vals], $logic);

  }
  else {
    # try to DWIM on equality operators
    return
      $op =~ $self->{equality_op}   ? $self->{sqlfalse}
    : $op =~ $self->{like_op}       ? belch("Supplying an empty arrayref to '@{[ uc $op]}' is deprecated") && $self->{sqlfalse}
    : $op =~ $self->{inequality_op} ? $self->{sqltrue}
    : $op =~ $self->{not_like_op}   ? belch("Supplying an empty arrayref to '@{[ uc $op]}' is deprecated") && $self->{sqltrue}
    : puke "operator '$op' applied on an empty array (field '$k')";
  }
}


sub _where_hashpair_SCALARREF {
  my ($self, $k, $v) = @_;
  $self->_debug("SCALAR($k) means literal SQL: $$v");
  my $sql = $self->_quote($k) . " " . $$v;
  return ($sql);
}

# literal SQL with bind
sub _where_hashpair_ARRAYREFREF {
  my ($self, $k, $v) = @_;
  $self->_debug("REF($k) means literal SQL: @${$v}");
  my ($sql, @bind) = @$$v;
  $self->_assert_bindval_matches_bindtype(@bind);
  $sql  = $self->_quote($k) . " " . $sql;
  return ($sql, @bind );
}

# literal SQL without bind
sub _where_hashpair_SCALAR {
  my ($self, $k, $v) = @_;
  $self->_debug("NOREF($k) means simple key=val: $k $self->{cmp} $v");
  my $sql = join ' ', $self->_convert($self->_quote($k)),
                      $self->_sqlcase($self->{cmp}),
                      $self->_convert('?');
  my @bind =  $self->_bindtype($k, $v);
  return ($sql, @bind);
}


sub _where_hashpair_UNDEF {
  my ($self, $k, $v) = @_;
  $self->_debug("UNDEF($k) means IS NULL");
  my $sql = $self->_quote($k) . $self->_sqlcase(' is null');
  return ($sql);
}

#======================================================================
# WHERE: TOP-LEVEL OTHERS (SCALARREF, SCALAR, UNDEF)
#======================================================================


sub _where_SCALARREF {
  my ($self, $where) = @_;

  # literal sql
  $self->_debug("SCALAR(*top) means literal SQL: $$where");
  return ($$where);
}


sub _where_SCALAR {
  my ($self, $where) = @_;

  # literal sql
  $self->_debug("NOREF(*top) means literal SQL: $where");
  return ($where);
}


sub _where_UNDEF {
  my ($self) = @_;
  return ();
}


#======================================================================
# WHERE: BUILTIN SPECIAL OPERATORS (-in, -between)
#======================================================================


sub _where_field_BETWEEN {
  my ($self, $k, $op, $vals) = @_;

  my ($label, $and, $placeholder);
  $label       = $self->_convert($self->_quote($k));
  $and         = ' ' . $self->_sqlcase('and') . ' ';
  $placeholder = $self->_convert('?');
  $op               = $self->_sqlcase($op);

  my $invalid_args = "Operator '$op' requires either an arrayref with two defined values or expressions, or a single literal scalarref/arrayref-ref";

  my ($clause, @bind) = $self->_SWITCH_refkind($vals, {
    ARRAYREFREF => sub {
      my ($s, @b) = @$$vals;
      $self->_assert_bindval_matches_bindtype(@b);
      ($s, @b);
    },
    SCALARREF => sub {
      return $$vals;
    },
    ARRAYREF => sub {
      puke $invalid_args if @$vals != 2;

      my (@all_sql, @all_bind);
      foreach my $val (@$vals) {
        my ($sql, @bind) = $self->_SWITCH_refkind($val, {
           SCALAR => sub {
             return ($placeholder, $self->_bindtype($k, $val) );
           },
           SCALARREF => sub {
             return $$val;
           },
           ARRAYREFREF => sub {
             my ($sql, @bind) = @$$val;
             $self->_assert_bindval_matches_bindtype(@bind);
             return ($sql, @bind);
           },
           HASHREF => sub {
             my ($func, $arg, @rest) = %$val;
             puke "Only simple { -func => arg } functions accepted as sub-arguments to BETWEEN"
               if (@rest or $func !~ /^ \- (.+)/x);
             $self->_where_unary_op($1 => $arg);
           },
           FALLBACK => sub {
             puke $invalid_args,
           },
        });
        push @all_sql, $sql;
        push @all_bind, @bind;
      }

      return (
        (join $and, @all_sql),
        @all_bind
      );
    },
    FALLBACK => sub {
      puke $invalid_args,
    },
  });

  my $sql = "( $label $op $clause )";
  return ($sql, @bind)
}


sub _where_field_IN {
  my ($self, $k, $op, $vals) = @_;

  # backwards compatibility: if scalar, force into an arrayref
  $vals = [$vals] if defined $vals && ! ref $vals;

  my ($label)       = $self->_convert($self->_quote($k));
  my ($placeholder) = $self->_convert('?');
  $op               = $self->_sqlcase($op);

  my ($sql, @bind) = $self->_SWITCH_refkind($vals, {
    ARRAYREF => sub {     # list of choices
      if (@$vals) { # nonempty list
        my (@all_sql, @all_bind);

        for my $val (@$vals) {
          my ($sql, @bind) = $self->_SWITCH_refkind($val, {
            SCALAR => sub {
              return ($placeholder, $val);
            },
            SCALARREF => sub {
              return $$val;
            },
            ARRAYREFREF => sub {
              my ($sql, @bind) = @$$val;
              $self->_assert_bindval_matches_bindtype(@bind);
              return ($sql, @bind);
            },
            HASHREF => sub {
              my ($func, $arg, @rest) = %$val;
              puke "Only simple { -func => arg } functions accepted as sub-arguments to IN"
                if (@rest or $func !~ /^ \- (.+)/x);
              $self->_where_unary_op($1 => $arg);
            },
            UNDEF => sub {
              puke(
                'SQL::Abstract before v1.75 used to generate incorrect SQL when the '
              . "-$op operator was given an undef-containing list: !!!AUDIT YOUR CODE "
              . 'AND DATA!!! (the upcoming Data::Query-based version of SQL::Abstract '
              . 'will emit the logically correct SQL instead of raising this exception)'
              );
            },
          });
          push @all_sql, $sql;
          push @all_bind, @bind;
        }

        return (
          sprintf('%s %s ( %s )',
            $label,
            $op,
            join(', ', @all_sql)
          ),
          $self->_bindtype($k, @all_bind),
        );
      }
      else { # empty list: some databases won't understand "IN ()", so DWIM
        my $sql = ($op =~ /\bnot\b/i) ? $self->{sqltrue} : $self->{sqlfalse};
        return ($sql);
      }
    },

    SCALARREF => sub {  # literal SQL
      my $sql = $self->_open_outer_paren($$vals);
      return ("$label $op ( $sql )");
    },
    ARRAYREFREF => sub {  # literal SQL with bind
      my ($sql, @bind) = @$$vals;
      $self->_assert_bindval_matches_bindtype(@bind);
      $sql = $self->_open_outer_paren($sql);
      return ("$label $op ( $sql )", @bind);
    },

    UNDEF => sub {
      puke "Argument passed to the '$op' operator can not be undefined";
    },

    FALLBACK => sub {
      puke "special op $op requires an arrayref (or scalarref/arrayref-ref)";
    },
  });

  return ($sql, @bind);
}

# Some databases (SQLite) treat col IN (1, 2) different from
# col IN ( (1, 2) ). Use this to strip all outer parens while
# adding them back in the corresponding method
sub _open_outer_paren {
  my ($self, $sql) = @_;

  while (my ($inner) = $sql =~ /^ \s* \( (.*) \) \s* $/xs) {

    # there are closing parens inside, need the heavy duty machinery
    # to reevaluate the extraction starting from $sql (full reevaluation)
    if ($inner =~ /\)/) {
      require Text::Balanced;

      my (undef, $remainder) = do {
        # idiotic design - writes to $@ but *DOES NOT* throw exceptions
        local $@;
        Text::Balanced::extract_bracketed($sql, '()', qr/\s*/);
      };

      # the entire expression needs to be a balanced bracketed thing
      # (after an extract no remainder sans trailing space)
      last if defined $remainder and $remainder =~ /\S/;
    }

    $sql = $inner;
  }

  $sql;
}


#======================================================================
# ORDER BY
#======================================================================

sub _order_by {
  my ($self, $arg) = @_;

  my (@sql, @bind);
  for my $c ($self->_order_by_chunks($arg) ) {
    $self->_SWITCH_refkind($c, {
      SCALAR => sub { push @sql, $c },
      ARRAYREF => sub { push @sql, shift @$c; push @bind, @$c },
    });
  }

  my $sql = @sql
    ? sprintf('%s %s',
        $self->_sqlcase(' order by'),
        join(', ', @sql)
      )
    : ''
  ;

  return wantarray ? ($sql, @bind) : $sql;
}

sub _order_by_chunks {
  my ($self, $arg) = @_;

  return $self->_SWITCH_refkind($arg, {

    ARRAYREF => sub {
      map { $self->_order_by_chunks($_ ) } @$arg;
    },

    ARRAYREFREF => sub {
      my ($s, @b) = @$$arg;
      $self->_assert_bindval_matches_bindtype(@b);
      [ $s, @b ];
    },

    SCALAR    => sub {$self->_quote($arg)},

    UNDEF     => sub {return () },

    SCALARREF => sub {$$arg}, # literal SQL, no quoting

    HASHREF   => sub {
      # get first pair in hash
      my ($key, $val, @rest) = %$arg;

      return () unless $key;

      if (@rest or not $key =~ /^-(desc|asc)/i) {
        puke "hash passed to _order_by must have exactly one key (-desc or -asc)";
      }

      my $direction = $1;

      my @ret;
      for my $c ($self->_order_by_chunks($val)) {
        my ($sql, @bind);

        $self->_SWITCH_refkind($c, {
          SCALAR => sub {
            $sql = $c;
          },
          ARRAYREF => sub {
            ($sql, @bind) = @$c;
          },
        });

        $sql = $sql . ' ' . $self->_sqlcase($direction);

        push @ret, [ $sql, @bind];
      }

      return @ret;
    },
  });
}


#======================================================================
# DATASOURCE (FOR NOW, JUST PLAIN TABLE OR LIST OF TABLES)
#======================================================================

sub _table  {
  my $self = shift;
  my $from = shift;
  $self->_SWITCH_refkind($from, {
    ARRAYREF     => sub {join ', ', map { $self->_quote($_) } @$from;},
    SCALAR       => sub {$self->_quote($from)},
    SCALARREF    => sub {$$from},
  });
}


#======================================================================
# UTILITY FUNCTIONS
#======================================================================

# highly optimized, as it's called way too often
sub _quote {
  # my ($self, $label) = @_;

  return '' unless defined $_[1];
  return ${$_[1]} if ref($_[1]) eq 'SCALAR';

  $_[0]->{quote_char} or
    ($_[0]->_assert_pass_injection_guard($_[1]), return $_[1]);

  my $qref = ref $_[0]->{quote_char};
  my ($l, $r) =
      !$qref             ? ($_[0]->{quote_char}, $_[0]->{quote_char})
    : ($qref eq 'ARRAY') ? @{$_[0]->{quote_char}}
    : puke "Unsupported quote_char format: $_[0]->{quote_char}";

  my $esc = $_[0]->{escape_char} || $r;

  # parts containing * are naturally unquoted
  return join($_[0]->{name_sep}||'', map
    +( $_ eq '*' ? $_ : do { (my $n = $_) =~ s/(\Q$esc\E|\Q$r\E)/$esc$1/g; $l . $n . $r } ),
    ( $_[0]->{name_sep} ? split (/\Q$_[0]->{name_sep}\E/, $_[1] ) : $_[1] )
  );
}


# Conversion, if applicable
sub _convert {
  #my ($self, $arg) = @_;
  if ($_[0]->{convert}) {
    return $_[0]->_sqlcase($_[0]->{convert}) .'(' . $_[1] . ')';
  }
  return $_[1];
}

# And bindtype
sub _bindtype {
  #my ($self, $col, @vals) = @_;
  # called often - tighten code
  return $_[0]->{bindtype} eq 'columns'
    ? map {[$_[1], $_]} @_[2 .. $#_]
    : @_[2 .. $#_]
  ;
}

# Dies if any element of @bind is not in [colname => value] format
# if bindtype is 'columns'.
sub _assert_bindval_matches_bindtype {
#  my ($self, @bind) = @_;
  my $self = shift;
  if ($self->{bindtype} eq 'columns') {
    for (@_) {
      if (!defined $_ || ref($_) ne 'ARRAY' || @$_ != 2) {
        puke "bindtype 'columns' selected, you need to pass: [column_name => bind_value]"
      }
    }
  }
}

sub _join_sql_clauses {
  my ($self, $logic, $clauses_aref, $bind_aref) = @_;

  if (@$clauses_aref > 1) {
    my $join  = " " . $self->_sqlcase($logic) . " ";
    my $sql = '( ' . join($join, @$clauses_aref) . ' )';
    return ($sql, @$bind_aref);
  }
  elsif (@$clauses_aref) {
    return ($clauses_aref->[0], @$bind_aref); # no parentheses
  }
  else {
    return (); # if no SQL, ignore @$bind_aref
  }
}


# Fix SQL case, if so requested
sub _sqlcase {
  # LDNOTE: if $self->{case} is true, then it contains 'lower', so we
  # don't touch the argument ... crooked logic, but let's not change it!
  return $_[0]->{case} ? $_[1] : uc($_[1]);
}


#======================================================================
# DISPATCHING FROM REFKIND
#======================================================================

sub _refkind {
  my ($self, $data) = @_;

  return 'UNDEF' unless defined $data;

  # blessed objects are treated like scalars
  my $ref = (Scalar::Util::blessed $data) ? '' : ref $data;

  return 'SCALAR' unless $ref;

  my $n_steps = 1;
  while ($ref eq 'REF') {
    $data = $$data;
    $ref = (Scalar::Util::blessed $data) ? '' : ref $data;
    $n_steps++ if $ref;
  }

  return ($ref||'SCALAR') . ('REF' x $n_steps);
}

sub _try_refkind {
  my ($self, $data) = @_;
  my @try = ($self->_refkind($data));
  push @try, 'SCALAR_or_UNDEF' if $try[0] eq 'SCALAR' || $try[0] eq 'UNDEF';
  push @try, 'FALLBACK';
  return \@try;
}

sub _METHOD_FOR_refkind {
  my ($self, $meth_prefix, $data) = @_;

  my $method;
  for (@{$self->_try_refkind($data)}) {
    $method = $self->can($meth_prefix."_".$_)
      and last;
  }

  return $method || puke "cannot dispatch on '$meth_prefix' for ".$self->_refkind($data);
}


sub _SWITCH_refkind {
  my ($self, $data, $dispatch_table) = @_;

  my $coderef;
  for (@{$self->_try_refkind($data)}) {
    $coderef = $dispatch_table->{$_}
      and last;
  }

  puke "no dispatch entry for ".$self->_refkind($data)
    unless $coderef;

  $coderef->();
}




#======================================================================
# VALUES, GENERATE, AUTOLOAD
#======================================================================

# LDNOTE: original code from nwiger, didn't touch code in that section
# I feel the AUTOLOAD stuff should not be the default, it should
# only be activated on explicit demand by user.

sub values {
    my $self = shift;
    my $data = shift || return;
    puke "Argument to ", __PACKAGE__, "->values must be a \\%hash"
        unless ref $data eq 'HASH';

    my @all_bind;
    foreach my $k (sort keys %$data) {
        my $v = $data->{$k};
        $self->_SWITCH_refkind($v, {
          ARRAYREF => sub {
            if ($self->{array_datatypes}) { # array datatype
              push @all_bind, $self->_bindtype($k, $v);
            }
            else {                          # literal SQL with bind
              my ($sql, @bind) = @$v;
              $self->_assert_bindval_matches_bindtype(@bind);
              push @all_bind, @bind;
            }
          },
          ARRAYREFREF => sub { # literal SQL with bind
            my ($sql, @bind) = @${$v};
            $self->_assert_bindval_matches_bindtype(@bind);
            push @all_bind, @bind;
          },
          SCALARREF => sub {  # literal SQL without bind
          },
          SCALAR_or_UNDEF => sub {
            push @all_bind, $self->_bindtype($k, $v);
          },
        });
    }

    return @all_bind;
}

sub generate {
    my $self  = shift;

    my(@sql, @sqlq, @sqlv);

    for (@_) {
        my $ref = ref $_;
        if ($ref eq 'HASH') {
            for my $k (sort keys %$_) {
                my $v = $_->{$k};
                my $r = ref $v;
                my $label = $self->_quote($k);
                if ($r eq 'ARRAY') {
                    # literal SQL with bind
                    my ($sql, @bind) = @$v;
                    $self->_assert_bindval_matches_bindtype(@bind);
                    push @sqlq, "$label = $sql";
                    push @sqlv, @bind;
                } elsif ($r eq 'SCALAR') {
                    # literal SQL without bind
                    push @sqlq, "$label = $$v";
                } else {
                    push @sqlq, "$label = ?";
                    push @sqlv, $self->_bindtype($k, $v);
                }
            }
            push @sql, $self->_sqlcase('set'), join ', ', @sqlq;
        } elsif ($ref eq 'ARRAY') {
            # unlike insert(), assume these are ONLY the column names, i.e. for SQL
            for my $v (@$_) {
                my $r = ref $v;
                if ($r eq 'ARRAY') {   # literal SQL with bind
                    my ($sql, @bind) = @$v;
                    $self->_assert_bindval_matches_bindtype(@bind);
                    push @sqlq, $sql;
                    push @sqlv, @bind;
                } elsif ($r eq 'SCALAR') {  # literal SQL without bind
                    # embedded literal SQL
                    push @sqlq, $$v;
                } else {
                    push @sqlq, '?';
                    push @sqlv, $v;
                }
            }
            push @sql, '(' . join(', ', @sqlq) . ')';
        } elsif ($ref eq 'SCALAR') {
            # literal SQL
            push @sql, $$_;
        } else {
            # strings get case twiddled
            push @sql, $self->_sqlcase($_);
        }
    }

    my $sql = join ' ', @sql;

    # this is pretty tricky
    # if ask for an array, return ($stmt, @bind)
    # otherwise, s/?/shift @sqlv/ to put it inline
    if (wantarray) {
        return ($sql, @sqlv);
    } else {
        1 while $sql =~ s/\?/my $d = shift(@sqlv);
                             ref $d ? $d->[1] : $d/e;
        return $sql;
    }
}


sub DESTROY { 1 }

sub AUTOLOAD {
    # This allows us to check for a local, then _form, attr
    my $self = shift;
    my($name) = $AUTOLOAD =~ /.*::(.+)/;
    return $self->generate($name, @_);
}

1;



__END__