Add --join-on-indent option to indent multi-keyword join ON clauses

lib/pgFormatter/Beautify.pm

@@ -168,6 +168,7 @@ Takes options as hash. Following options are recognized:
 
 =item * compact_clause_body - keep the first element of a clause on the keyword line
 
+=item * join_on_indent - indent the ON clause continuation lines (AND/OR) of a multi-keyword join (e.g. LEFT OUTER JOIN) one level below the join keyword
 =item * isolate_semicolon - place the statement terminating semicolon on its own line
 when the statement spans several lines
 
@@ -189,6 +190,7 @@ sub new {
 	$self->set_defaults();
 
 	for my $key (
+		qw( query spaces space break wrap keywords functions rules uc_keywords uc_functions uc_types uc_identifiers no_comments no_grouping placeholder multiline separator comma comma_break format colorize format_type wrap_limit wrap_after wrap_comment numbering redshift no_extra_line keep_newline no_space_function compact_clause_body join_on_indent redundant_parenthesis vertical_align)
 		qw( query spaces space break wrap keywords functions rules uc_keywords uc_functions uc_types uc_identifiers no_comments no_grouping placeholder multiline separator comma comma_break format colorize format_type wrap_limit wrap_after wrap_comment numbering redshift no_extra_line keep_newline no_space_function compact_clause_body isolate_semicolon redundant_parenthesis vertical_align)
 	  )
 	{
@@ -4119,7 +4121,14 @@ sub beautify {
 			and ( not defined $last or uc($last) ne 'MATCH' ) )
 		{
 			$self->{'no_break'} = 0;
-			if ( !$self->{'_is_in_join'} and ( defined $last and $last ne ')' ) ) {
+			# When join_on_indent is enabled, only step back once per join clause:
+			# a join spelled with several keywords, such as LEFT OUTER JOIN, must
+			# not step back once per keyword or it loses one indentation level.
+			if (    !$self->{'_is_in_join'}
+				and ( defined $last and $last ne ')' )
+				and ( !$self->{'join_on_indent'}
+					or $last !~ /^(?:LEFT|RIGHT|FULL|INNER|OUTER|CROSS|NATURAL)$/i ) )
+			{
 				$self->_back( $token, $last ) if ($#{ $self->{'_level_stack'} } < 0 or $self->{'_level'} > $self->{'_level_stack'}[-1]+1);
 			}
 			if ( $self->{'_has_over_in_join'} ) {
@@ -5760,6 +5769,7 @@ Currently defined defaults:
 
 =item compact_clause_body => 0
 
+=item join_on_indent => 0
 =item isolate_semicolon => 0
 
 =item redundant_parenthesis => 0
@@ -5809,6 +5819,7 @@ sub set_defaults {
 	$self->{'keep_newline'}          = 0;
 	$self->{'no_space_function'}     = 0;
 	$self->{'compact_clause_body'}   = 0;
+	$self->{'join_on_indent'}        = 0;
 	$self->{'isolate_semicolon'}     = 0;
 	$self->{'_stmt_start_offset'}    = 0;
 	$self->{'_stmt_started'}         = 0;

lib/pgFormatter/CLI.pm

@@ -131,6 +131,7 @@ sub beautify {
 	$args{'extra_keyword'}         = $self->{'cfg'}->{'extra-keyword'};
 	$args{'no_space_function'}     = $self->{'cfg'}->{'no-space-function'};
 	$args{'compact_clause_body'}   = $self->{'cfg'}->{'compact-clause-body'};
+	$args{'join_on_indent'}        = $self->{'cfg'}->{'join-on-indent'};
 	$args{'isolate_semicolon'}     = $self->{'cfg'}->{'isolate-semicolon'};
 	$args{'redundant_parenthesis'} = $self->{'cfg'}->{'redundant-parenthesis'};
 	$args{'vertical_align'}        = $self->{'cfg'}->{'vertical-align'};
@@ -334,6 +335,9 @@ Options:
     --compact-clause-body : keep the first element of a FROM, WHERE, SET, RETURNING,
                             HAVING or VALUES clause on the same line as the keyword,
                             and the body of a CASE ... THEN on the same line as THEN.
+    --join-on-indent      : indent the ON clause continuation lines (AND/OR) of a
+                            multi-keyword join (e.g. LEFT OUTER JOIN) one level
+                            below the join keyword.
     --isolate-semicolon : place the statement terminating semicolon on its own line
                             instead of appending it to the last token, unless the
                             whole statement fits on a single line.
@@ -407,6 +411,7 @@ sub get_command_line_args {
 		'wrap-limit|w=i',  'wrap-after|W=i',
 		'inplace|i!',      'extra-function=s',
 		'extra-keyword=s', 'no-space-function!',
+		'compact-clause-body!', 'join-on-indent!', 'ident-case|I=i',
 		'compact-clause-body!', 'ident-case|I=i', 'isolate-semicolon!',
 		'redundant-parenthesis!', 'vertical-align!',
 	);

t/02_regress.t

@@ -32,6 +32,7 @@ foreach my $f (@files)
 	$opt = "--compact-clause-body" if ($f =~ m#/ex82.sql$#);
 	$opt = "--no-space-function" if ($f =~ m#/ex83.sql$#);
 	$opt = "--ident-case 2 -f 1 -U 1" if ($f =~ m#/ex84\.sql$#);
+	$opt = "--join-on-indent" if ($f =~ m#/ex85.sql$#);
 	$opt = "--isolate-semicolon" if ($f =~ m#/ex85.sql$#);
 	if ($f =~ m#/ex61.sql$#)
 	{

t/test-files/ex85.sql

@@ -1,3 +1,28 @@
+SELECT
+    tyap0.tyap_code
+    , appel.frap_tyap_code
+FROM
+    tyap
+    LEFT OUTER JOIN ab_frap@link_serveur appel ON appel.frap_tyap_code = tyap.tyap_code
+        AND appel.frap_imme_no = tyap.tyap_imme_no
+    LEFT OUTER JOIN bud ON bud.budg_tyap_direct = tyap.tyap_direct;
+
+SELECT
+    a.id
+FROM
+    a
+    INNER JOIN b ON b.id = a.id
+    CROSS JOIN c ON true
+    NATURAL JOIN d ON true
+    RIGHT JOIN e ON e.id = a.id
+    FULL JOIN f ON f.id = a.id;
+
+SELECT
+    x.v
+FROM
+    x
+    JOIN y ON y.k = x.k
+    LEFT JOIN z ON z.k = x.k;
 DO $$
 BEGIN
 IF true THEN

t/test-files/expected/ex85.sql

@@ -1,3 +1,28 @@
+SELECT
+    tyap0.tyap_code,
+    appel.frap_tyap_code
+FROM
+    tyap
+    LEFT OUTER JOIN ab_frap@link_serveur appel ON appel.frap_tyap_code = tyap.tyap_code
+        AND appel.frap_imme_no = tyap.tyap_imme_no
+    LEFT OUTER JOIN bud ON bud.budg_tyap_direct = tyap.tyap_direct;
+
+SELECT
+    a.id
+FROM
+    a
+    INNER JOIN b ON b.id = a.id
+    CROSS JOIN c ON TRUE
+    NATURAL JOIN d ON TRUE
+    RIGHT JOIN e ON e.id = a.id
+    FULL JOIN f ON f.id = a.id;
+
+SELECT
+    x.v
+FROM
+    x
+    JOIN y ON y.k = x.k
+    LEFT JOIN z ON z.k = x.k;
 DO $$
 BEGIN
     IF TRUE THEN