initial register code for EC plugin

[scpubgit/Q-Branch.git] / lib / SQL / Abstract / ExtraClauses.pm

diff --git a/lib/SQL/Abstract/ExtraClauses.pm b/lib/SQL/Abstract/ExtraClauses.pm
index 808ff0d..c0e753d 100644 (file)
--- a/lib/SQL/Abstract/ExtraClauses.pm
+++ b/lib/SQL/Abstract/ExtraClauses.pm
@@ -5,8 +5,7 @@ use Moo;
 has sqla => (
   is => 'ro', init_arg => undef,
   handles => [ qw(
-    expand_expr expand_maybe_list_expr render_aqt
-    format_keyword join_query_parts
+    expand_expr expand_maybe_list_expr render_aqt join_query_parts
   ) ],
 );
 
@@ -18,9 +17,25 @@ sub cb {
   };
 }
 
+sub register {
+  my ($self, $method, @pairs) = @_;
+  my $sqla = $self->sqla;
+  while (my ($car, $cdr) = splice(@pairs, 0, 2)) {
+    my $cb = $self->cb($cdr);
+    $sqla->$method($car, $cb);
+  }
+  return $self;
+}
+
 sub apply_to {
   my ($self, $sqla) = @_;
   $self = $self->new unless ref($self);
+  local $self->{sqla} = $sqla;
+  $self->register_extensions($sqla);
+}
+
+sub register_extensions {
+  my ($self, $sqla) = @_;
   my @clauses = $sqla->clauses_of('select');
   my @before_setop;
   CLAUSE: foreach my $idx (0..$#clauses) {
@@ -32,18 +47,18 @@ sub apply_to {
   }
   die "Huh?" unless @before_setop;
   $sqla->clauses_of(select => 'with', @clauses);
-  $sqla->clause_expanders(
-    'select.group_by', $self->cb(sub {
-      $_[0]->expand_maybe_list_expr($_[2], -ident)
-    }),
-    'select.having', $self->cb(sub { $_[0]->expand_expr($_[2]) }),
+  $self->register(
+    clause_expanders =>
+      'select.group_by'
+        => sub { $_[0]->expand_maybe_list_expr($_[2], -ident) },
+      'select.having'
+        => sub { $_[0]->expand_expr($_[2]) },
   );
   foreach my $thing (qw(join from_list)) {
     $sqla->expander($thing => $self->cb("_expand_${thing}"))
          ->renderer($thing => $self->cb("_render_${thing}"))
   }
-  $sqla->op_expander(as => $self->cb('_expand_op_as'));
-  $sqla->expander(as => $self->cb('_expand_op_as'));
+  $sqla->binop_expander(as => $self->cb('_expand_op_as'));
   $sqla->renderer(as => $self->cb('_render_as'));
   $sqla->expander(alias => $self->cb('_expand_alias'));
   $sqla->renderer(alias => $self->cb('_render_alias'));
@@ -76,10 +91,9 @@ sub apply_to {
     $self->cb('_expand_select', $_[0], \@before_setop);
   });
 
-  $sqla->clause_renderer('select.setop' => $self->cb(sub {
-    my ($self, undef, $setop) = @_;
-    $self->render_aqt($setop);
-  }));
+  $sqla->clause_renderer(
+    'select.setop' => $self->cb(sub { $_[0]->render_aqt($_[2]); })
+  );
 
   foreach my $setop (qw(union intersect except)) {
     $sqla->expander($setop => $self->cb('_expand_setop'));
@@ -189,14 +203,14 @@ sub _render_join {
 
   my @parts = (
     $args->{from},
-    $self->format_keyword(join '_', ($args->{type}||()), 'join'),
+    { -keyword => join '_', ($args->{type}||()), 'join' },
     (map +($_->{-ident} || $_->{-as} ? $_ : ('(', $_, ')')), $args->{to}),
     ($args->{on} ? (
-      $self->format_keyword('on') ,
+      { -keyword => 'on' },
       $args->{on},
     ) : ()),
     ($args->{using} ? (
-      $self->format_keyword('using'),
+      { -keyword => 'using' },
       '(', $args->{using}, ')',
     ) : ()),
   );
@@ -206,7 +220,6 @@ sub _render_join {
 sub _expand_op_as {
   my ($self, undef, $vv, $k) = @_;
   my @vv = (ref($vv) eq 'ARRAY' ? @$vv : $vv);
-  $k ||= shift @vv;
   my $ik = $self->expand_expr($k, -ident);
   return +{ -as => [ $ik, $self->expand_expr($vv[0], -alias) ] }
     if @vv == 1 and ref($vv[0]) eq 'HASH';
@@ -221,7 +234,7 @@ sub _render_as {
   return $self->join_query_parts(
     ' ',
     $thing,
-    $self->format_keyword('as'),
+    { -keyword => 'as' },
     $alias,
   );
 }
@@ -302,13 +315,13 @@ sub _render_with {
       my ($alias, $query) = @$_;
       $self->join_query_parts(' ',
           $alias,
-          $self->format_keyword('as'),
+          { -keyword => 'as' },
           $query,
       )
     } @{$with->{queries}}
   );
   return $self->join_query_parts(' ',
-    $self->format_keyword(join '_', 'with', ($with->{type}||'')),
+    { -keyword => join '_', 'with', ($with->{type}||'') },
     $q_part,
   );
 }
@@ -324,7 +337,7 @@ sub _expand_setop {
 sub _render_setop {
   my ($self, $setop, $args) = @_;
   $self->join_query_parts(
-    ' '.$self->format_keyword(join '_', $setop, ($args->{type}||())).' ',
+    { -keyword => ' '.join('_', $setop, ($args->{type}||())).' ' },
     @{$args->{queries}}
   );
 }
@@ -341,3 +354,101 @@ sub _expand_clause_setop {
 }
 
 1;
+
+__END__
+
+=head1 NAME
+
+SQL::Abstract::ExtraClauses - new/experimental additions to L<SQL::Abstract>
+
+=head1 SYNOPSIS
+
+  my $sqla = SQL::Abstract->new;
+  SQL::Abstract::ExtraClauses->apply_to($sqla);
+
+=head1 METHODS
+
+=head2 apply_to
+
+Applies the plugin to an L<SQL::Abstract> object.
+
+=head2 cb
+
+For plugin authors, creates a callback to call a method on the plugin.
+
+=head2 sqla
+
+Available only during plugin callback executions, contains the currently
+active L<SQL::Abstract> object.
+
+=head1 NODE TYPES
+
+=head2 alias
+
+Represents a table alias. Expands name and column names with ident as default.
+
+  # expr
+  { -alias => [ 't', 'x', 'y', 'z' ] }
+
+  # aqt
+  { -alias => [
+      { -ident => [ 't' ] }, { -ident => [ 'x' ] },
+      { -ident => [ 'y' ] }, { -ident => [ 'z' ] },
+  ] }
+
+  # query
+  t(x, y, z)
+  []
+
+=head2 as
+
+Represents an sql AS. LHS is expanded with ident as default, RHS is treated
+as a list of arguments for the alias node.
+
+  # expr
+  { foo => { -as => 'bar' } }
+
+  # aqt
+  { -as =>
+      [
+        { -ident => [ 'foo' ] },
+        { -alias => [ { -ident => [ 'bar' ] } ] },
+      ]
+  }
+
+  # query
+  foo AS bar
+  []
+
+  # expr
+  { -as => [ { -select => { _ => 'blah' } }, 't', 'blah' ] }
+
+  # aqt
+  { -as => [
+      { -select =>
+          { select => { -op => [ ',', { -ident => [ 'blah' ] } ] } }
+      },
+      { -alias => [ { -ident => [ 't' ] }, { -ident => [ 'blah' ] } ] },
+  ] }
+
+  # query
+  (SELECT blah) AS t(blah)
+  []
+
+=head2 cast
+
+  # expr
+  { -cast => [ { -ident => 'birthday' }, 'date' ] }
+
+  # aqt
+  { -func => [
+      'cast', {
+        -as => [ { -ident => [ 'birthday' ] }, { -ident => [ 'date' ] } ]
+      },
+  ] }
+
+  # query
+  CAST(birthday AS date)
+  []
+
+=cut