-- |
-- Names for nodes mostly resemble the according definitions in the @gram.y@
-- original Postgres parser file, except for the cases where we can optimize on that.
--
-- For reasoning see the docs of the parsing module of this project.
module PostgresqlSyntax.Ast where

import PostgresqlSyntax.Prelude hiding (Op, Order)

-- * Statement

-- |
-- ==== References
-- @
-- PreparableStmt:
--   |  SelectStmt
--   |  InsertStmt
--   |  UpdateStmt
--   |  DeleteStmt
--   |  CallStmt
-- @
data PreparableStmt
  = SelectPreparableStmt SelectStmt
  | InsertPreparableStmt InsertStmt
  | UpdatePreparableStmt UpdateStmt
  | DeletePreparableStmt DeleteStmt
  | CallPreparableStmt CallStmt
  deriving (Show, Generic, Eq, Ord)

-- * Call

newtype CallStmt
  = CallStmt FuncApplication
  deriving (Show, Generic, Eq, Ord)

-- * Insert

-- |
-- ==== References
-- @
-- InsertStmt:
--   | opt_with_clause INSERT INTO insert_target insert_rest
--       opt_on_conflict returning_clause
-- @
data InsertStmt = InsertStmt (Maybe WithClause) InsertTarget InsertRest (Maybe OnConflict) (Maybe ReturningClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- insert_target:
--   | qualified_name
--   | qualified_name AS ColId
-- @
data InsertTarget = InsertTarget QualifiedName (Maybe ColId)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- insert_rest:
--   | SelectStmt
--   | OVERRIDING override_kind VALUE_P SelectStmt
--   | '(' insert_column_list ')' SelectStmt
--   | '(' insert_column_list ')' OVERRIDING override_kind VALUE_P SelectStmt
--   | DEFAULT VALUES
-- @
data InsertRest
  = SelectInsertRest (Maybe InsertColumnList) (Maybe OverrideKind) SelectStmt
  | DefaultValuesInsertRest
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- override_kind:
--   | USER
--   | SYSTEM_P
-- @
data OverrideKind = UserOverrideKind | SystemOverrideKind
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

-- |
-- ==== References
-- @
-- insert_column_list:
--   | insert_column_item
--   | insert_column_list ',' insert_column_item
-- @
type InsertColumnList = NonEmpty InsertColumnItem

-- |
-- ==== References
-- @
-- insert_column_item:
--   | ColId opt_indirection
-- @
data InsertColumnItem = InsertColumnItem ColId (Maybe Indirection)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_on_conflict:
--   | ON CONFLICT opt_conf_expr DO UPDATE SET set_clause_list where_clause
--   | ON CONFLICT opt_conf_expr DO NOTHING
--   | EMPTY
-- @
data OnConflict = OnConflict (Maybe ConfExpr) OnConflictDo
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_on_conflict:
--   | ON CONFLICT opt_conf_expr DO UPDATE SET set_clause_list where_clause
--   | ON CONFLICT opt_conf_expr DO NOTHING
--   | EMPTY
-- @
data OnConflictDo
  = UpdateOnConflictDo SetClauseList (Maybe WhereClause)
  | NothingOnConflictDo
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_conf_expr:
--   | '(' index_params ')' where_clause
--   | ON CONSTRAINT name
--   | EMPTY
-- @
data ConfExpr
  = WhereConfExpr IndexParams (Maybe WhereClause)
  | ConstraintConfExpr Name
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- returning_clause:
--   | RETURNING target_list
--   | EMPTY
-- @
type ReturningClause = TargetList

-- * Update

-- |
-- ==== References
-- @
-- UpdateStmt:
--   | opt_with_clause UPDATE relation_expr_opt_alias
--       SET set_clause_list
--       from_clause
--       where_or_current_clause
--       returning_clause
-- @
data UpdateStmt = UpdateStmt (Maybe WithClause) RelationExprOptAlias SetClauseList (Maybe FromClause) (Maybe WhereOrCurrentClause) (Maybe ReturningClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- set_clause_list:
--   | set_clause
--   | set_clause_list ',' set_clause
-- @
type SetClauseList = NonEmpty SetClause

-- |
-- ==== References
-- @
-- set_clause:
--   | set_target '=' a_expr
--   | '(' set_target_list ')' '=' a_expr
-- @
data SetClause
  = TargetSetClause SetTarget AExpr
  | TargetListSetClause SetTargetList AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- set_target:
--   | ColId opt_indirection
-- @
data SetTarget = SetTarget ColId (Maybe Indirection)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- set_target_list:
--   | set_target
--   | set_target_list ',' set_target
-- @
type SetTargetList = NonEmpty SetTarget

-- * Delete

-- |
-- ==== References
-- @
-- DeleteStmt:
--   | opt_with_clause DELETE_P FROM relation_expr_opt_alias
--       using_clause where_or_current_clause returning_clause
-- @
data DeleteStmt = DeleteStmt (Maybe WithClause) RelationExprOptAlias (Maybe UsingClause) (Maybe WhereOrCurrentClause) (Maybe ReturningClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- using_clause:
--   | USING from_list
--   | EMPTY
-- @
type UsingClause = FromList

-- * Select

-- |
-- ==== References
-- @
-- SelectStmt:
--   |  select_no_parens
--   |  select_with_parens
-- @
type SelectStmt = Either SelectNoParens SelectWithParens

-- |
-- ==== References
-- @
-- select_with_parens:
--   |  '(' select_no_parens ')'
--   |  '(' select_with_parens ')'
-- @
data SelectWithParens
  = NoParensSelectWithParens SelectNoParens
  | WithParensSelectWithParens SelectWithParens
  deriving (Show, Generic, Eq, Ord)

-- |
-- Covers the following cases:
--
-- @
-- select_no_parens:
--   |  simple_select
--   |  select_clause sort_clause
--   |  select_clause opt_sort_clause for_locking_clause opt_select_limit
--   |  select_clause opt_sort_clause select_limit opt_for_locking_clause
--   |  with_clause select_clause
--   |  with_clause select_clause sort_clause
--   |  with_clause select_clause opt_sort_clause for_locking_clause opt_select_limit
--   |  with_clause select_clause opt_sort_clause select_limit opt_for_locking_clause
-- @
data SelectNoParens
  = SelectNoParens (Maybe WithClause) SelectClause (Maybe SortClause) (Maybe SelectLimit) (Maybe ForLockingClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- @
-- select_clause:
--   |  simple_select
--   |  select_with_parens
-- @
type SelectClause = Either SimpleSelect SelectWithParens

-- |
-- ==== References
-- @
-- simple_select:
--   |  SELECT opt_all_clause opt_target_list
--       into_clause from_clause where_clause
--       group_clause having_clause window_clause
--   |  SELECT distinct_clause target_list
--       into_clause from_clause where_clause
--       group_clause having_clause window_clause
--   |  values_clause
--   |  TABLE relation_expr
--   |  select_clause UNION all_or_distinct select_clause
--   |  select_clause INTERSECT all_or_distinct select_clause
--   |  select_clause EXCEPT all_or_distinct select_clause
-- @
data SimpleSelect
  = NormalSimpleSelect (Maybe Targeting) (Maybe IntoClause) (Maybe FromClause) (Maybe WhereClause) (Maybe GroupClause) (Maybe HavingClause) (Maybe WindowClause)
  | ValuesSimpleSelect ValuesClause
  | TableSimpleSelect RelationExpr
  | BinSimpleSelect SelectBinOp SelectClause (Maybe Bool) SelectClause
  deriving (Show, Generic, Eq, Ord)

-- |
-- Covers these parts of spec:
--
-- ==== References
-- @
-- simple_select:
--   |  SELECT opt_all_clause opt_target_list
--       into_clause from_clause where_clause
--       group_clause having_clause window_clause
--   |  SELECT distinct_clause target_list
--       into_clause from_clause where_clause
--       group_clause having_clause window_clause
--
-- distinct_clause:
--   |  DISTINCT
--   |  DISTINCT ON '(' expr_list ')'
-- @
data Targeting
  = NormalTargeting TargetList
  | AllTargeting (Maybe TargetList)
  | DistinctTargeting (Maybe ExprList) TargetList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- target_list:
--   | target_el
--   | target_list ',' target_el
-- @
type TargetList = NonEmpty TargetEl

-- |
-- ==== References
-- @
-- target_el:
--   |  a_expr AS ColLabel
--   |  a_expr IDENT
--   |  a_expr
--   |  '*'
-- @
data TargetEl
  = AliasedExprTargetEl AExpr Ident
  | ImplicitlyAliasedExprTargetEl AExpr Ident
  | ExprTargetEl AExpr
  | AsteriskTargetEl
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
--   |  select_clause UNION all_or_distinct select_clause
--   |  select_clause INTERSECT all_or_distinct select_clause
--   |  select_clause EXCEPT all_or_distinct select_clause
-- @
data SelectBinOp = UnionSelectBinOp | IntersectSelectBinOp | ExceptSelectBinOp
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- with_clause:
--   |  WITH cte_list
--   |  WITH_LA cte_list
--   |  WITH RECURSIVE cte_list
-- @
data WithClause = WithClause Bool (NonEmpty CommonTableExpr)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- common_table_expr:
--   |  name opt_name_list AS opt_materialized '(' PreparableStmt ')'
-- opt_materialized:
--   | MATERIALIZED
--   | NOT MATERIALIZED
--   | EMPTY
-- @
data CommonTableExpr = CommonTableExpr Ident (Maybe (NonEmpty Ident)) (Maybe Bool) PreparableStmt
  deriving (Show, Generic, Eq, Ord)

type IntoClause = OptTempTableName

-- |
-- ==== References
-- @
-- OptTempTableName:
--   |  TEMPORARY opt_table qualified_name
--   |  TEMP opt_table qualified_name
--   |  LOCAL TEMPORARY opt_table qualified_name
--   |  LOCAL TEMP opt_table qualified_name
--   |  GLOBAL TEMPORARY opt_table qualified_name
--   |  GLOBAL TEMP opt_table qualified_name
--   |  UNLOGGED opt_table qualified_name
--   |  TABLE qualified_name
--   |  qualified_name
-- @
data OptTempTableName
  = TemporaryOptTempTableName Bool QualifiedName
  | TempOptTempTableName Bool QualifiedName
  | LocalTemporaryOptTempTableName Bool QualifiedName
  | LocalTempOptTempTableName Bool QualifiedName
  | GlobalTemporaryOptTempTableName Bool QualifiedName
  | GlobalTempOptTempTableName Bool QualifiedName
  | UnloggedOptTempTableName Bool QualifiedName
  | TableOptTempTableName QualifiedName
  | QualifedOptTempTableName QualifiedName
  deriving (Show, Generic, Eq, Ord)

type FromClause = NonEmpty TableRef

type GroupClause = NonEmpty GroupByItem

-- |
-- ==== References
-- @
-- group_by_item:
--   |  a_expr
--   |  empty_grouping_set
--   |  cube_clause
--   |  rollup_clause
--   |  grouping_sets_clause
-- empty_grouping_set:
--   |  '(' ')'
-- rollup_clause:
--   |  ROLLUP '(' expr_list ')'
-- cube_clause:
--   |  CUBE '(' expr_list ')'
-- grouping_sets_clause:
--   |  GROUPING SETS '(' group_by_list ')'
-- @
data GroupByItem
  = ExprGroupByItem AExpr
  | EmptyGroupingSetGroupByItem
  | RollupGroupByItem ExprList
  | CubeGroupByItem ExprList
  | GroupingSetsGroupByItem (NonEmpty GroupByItem)
  deriving (Show, Generic, Eq, Ord)

-- |
-- @
-- having_clause:
--   |  HAVING a_expr
--   |  EMPTY
-- @
type HavingClause = AExpr

-- |
-- @
-- window_clause:
--   |  WINDOW window_definition_list
--   |  EMPTY
--
-- window_definition_list:
--   |  window_definition
--   |  window_definition_list ',' window_definition
-- @
type WindowClause = NonEmpty WindowDefinition

-- |
-- @
-- window_definition:
--   |  ColId AS window_specification
-- @
data WindowDefinition = WindowDefinition Ident WindowSpecification
  deriving (Show, Generic, Eq, Ord)

-- |
-- @
-- window_specification:
--   |  '(' opt_existing_window_name opt_partition_clause
--             opt_sort_clause opt_frame_clause ')'
--
-- opt_existing_window_name:
--   |  ColId
--   |  EMPTY
--
-- opt_partition_clause:
--   |  PARTITION BY expr_list
--   |  EMPTY
-- @
data WindowSpecification = WindowSpecification (Maybe ExistingWindowName) (Maybe PartitionClause) (Maybe SortClause) (Maybe FrameClause)
  deriving (Show, Generic, Eq, Ord)

type ExistingWindowName = ColId

type PartitionClause = ExprList

-- |
-- ==== References
-- @
-- opt_frame_clause:
--   |  RANGE frame_extent opt_window_exclusion_clause
--   |  ROWS frame_extent opt_window_exclusion_clause
--   |  GROUPS frame_extent opt_window_exclusion_clause
--   |  EMPTY
-- @
data FrameClause = FrameClause FrameClauseMode FrameExtent (Maybe WindowExclusionClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_frame_clause:
--   |  RANGE frame_extent opt_window_exclusion_clause
--   |  ROWS frame_extent opt_window_exclusion_clause
--   |  GROUPS frame_extent opt_window_exclusion_clause
--   |  EMPTY
-- @
data FrameClauseMode = RangeFrameClauseMode | RowsFrameClauseMode | GroupsFrameClauseMode
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- frame_extent:
--   |  frame_bound
--   |  BETWEEN frame_bound AND frame_bound
-- @
data FrameExtent = SingularFrameExtent FrameBound | BetweenFrameExtent FrameBound FrameBound
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- frame_bound:
--   |  UNBOUNDED PRECEDING
--   |  UNBOUNDED FOLLOWING
--   |  CURRENT_P ROW
--   |  a_expr PRECEDING
--   |  a_expr FOLLOWING
-- @
data FrameBound
  = UnboundedPrecedingFrameBound
  | UnboundedFollowingFrameBound
  | CurrentRowFrameBound
  | PrecedingFrameBound AExpr
  | FollowingFrameBound AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_window_exclusion_clause:
--   |  EXCLUDE CURRENT_P ROW
--   |  EXCLUDE GROUP_P
--   |  EXCLUDE TIES
--   |  EXCLUDE NO OTHERS
--   |  EMPTY
-- @
data WindowExclusionClause
  = CurrentRowWindowExclusionClause
  | GroupWindowExclusionClause
  | TiesWindowExclusionClause
  | NoOthersWindowExclusionClause
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- values_clause:
--   |  VALUES '(' expr_list ')'
--   |  values_clause ',' '(' expr_list ')'
-- @
type ValuesClause = NonEmpty ExprList

-- |
--
-- sort_clause:
--   |  ORDER BY sortby_list
--
-- sortby_list:
--   |  sortby
--   |  sortby_list ',' sortby
type SortClause = NonEmpty SortBy

-- |
-- ==== References
-- @
-- sortby:
--   |  a_expr USING qual_all_Op opt_nulls_order
--   |  a_expr opt_asc_desc opt_nulls_order
-- @
data SortBy
  = UsingSortBy AExpr QualAllOp (Maybe NullsOrder)
  | AscDescSortBy AExpr (Maybe AscDesc) (Maybe NullsOrder)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- select_limit:
--   | limit_clause offset_clause
--   | offset_clause limit_clause
--   | limit_clause
--   | offset_clause
-- @
data SelectLimit
  = LimitOffsetSelectLimit LimitClause OffsetClause
  | OffsetLimitSelectLimit OffsetClause LimitClause
  | LimitSelectLimit LimitClause
  | OffsetSelectLimit OffsetClause
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- limit_clause:
--   | LIMIT select_limit_value
--   | LIMIT select_limit_value ',' select_offset_value
--   | FETCH first_or_next select_fetch_first_value row_or_rows ONLY
--   | FETCH first_or_next row_or_rows ONLY
-- select_offset_value:
--   | a_expr
-- first_or_next:
--   | FIRST_P
--   | NEXT
-- row_or_rows:
--   | ROW
--   | ROWS
-- @
data LimitClause
  = LimitLimitClause SelectLimitValue (Maybe AExpr)
  | FetchOnlyLimitClause Bool (Maybe SelectFetchFirstValue) Bool
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- select_fetch_first_value:
--   | c_expr
--   | '+' I_or_F_const
--   | '-' I_or_F_const
-- @
data SelectFetchFirstValue
  = ExprSelectFetchFirstValue CExpr
  | NumSelectFetchFirstValue Bool (Either Int64 Double)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- select_limit_value:
--   | a_expr
--   | ALL
-- @
data SelectLimitValue
  = ExprSelectLimitValue AExpr
  | AllSelectLimitValue
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- offset_clause:
--   | OFFSET select_offset_value
--   | OFFSET select_fetch_first_value row_or_rows
-- select_offset_value:
--   | a_expr
-- row_or_rows:
--   | ROW
--   | ROWS
-- @
data OffsetClause
  = ExprOffsetClause AExpr
  | FetchFirstOffsetClause SelectFetchFirstValue Bool
  deriving (Show, Generic, Eq, Ord)

-- * For Locking

-- |
-- ==== References
-- @
-- for_locking_clause:
--   | for_locking_items
--   | FOR READ ONLY
-- for_locking_items:
--   | for_locking_item
--   | for_locking_items for_locking_item
-- @
data ForLockingClause
  = ItemsForLockingClause (NonEmpty ForLockingItem)
  | ReadOnlyForLockingClause
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- for_locking_item:
--   | for_locking_strength locked_rels_list opt_nowait_or_skip
-- locked_rels_list:
--   | OF qualified_name_list
--   | EMPTY
-- opt_nowait_or_skip:
--   | NOWAIT
--   | SKIP LOCKED
--   | EMPTY
-- @
data ForLockingItem = ForLockingItem ForLockingStrength (Maybe (NonEmpty QualifiedName)) (Maybe Bool)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- for_locking_strength:
--   | FOR UPDATE
--   | FOR NO KEY UPDATE
--   | FOR SHARE
--   | FOR KEY SHARE
-- @
data ForLockingStrength
  = UpdateForLockingStrength
  | NoKeyUpdateForLockingStrength
  | ShareForLockingStrength
  | KeyForLockingStrength
  deriving (Show, Generic, Eq, Ord)

-- * Table references and joining

-- |
-- ==== References
-- @
-- from_list:
--   | table_ref
--   | from_list ',' table_ref
-- @
type FromList = NonEmpty TableRef

-- |
-- ==== References
-- @
-- | relation_expr opt_alias_clause
-- | relation_expr opt_alias_clause tablesample_clause
-- | func_table func_alias_clause
-- | LATERAL_P func_table func_alias_clause
-- | xmltable opt_alias_clause
-- | LATERAL_P xmltable opt_alias_clause
-- | select_with_parens opt_alias_clause
-- | LATERAL_P select_with_parens opt_alias_clause
-- | joined_table
-- | '(' joined_table ')' alias_clause
--
-- TODO: Add xmltable
-- @
data TableRef
  = -- |
    -- @
    --    | relation_expr opt_alias_clause
    --    | relation_expr opt_alias_clause tablesample_clause
    -- @
    RelationExprTableRef RelationExpr (Maybe AliasClause) (Maybe TablesampleClause)
  | -- |
    -- @
    --    | func_table func_alias_clause
    --    | LATERAL_P func_table func_alias_clause
    -- @
    FuncTableRef Bool FuncTable (Maybe FuncAliasClause)
  | -- |
    -- @
    --    | select_with_parens opt_alias_clause
    --    | LATERAL_P select_with_parens opt_alias_clause
    -- @
    SelectTableRef Bool SelectWithParens (Maybe AliasClause)
  | -- |
    -- @
    --    | joined_table
    --    | '(' joined_table ')' alias_clause
    -- @
    JoinTableRef JoinedTable (Maybe AliasClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- | qualified_name
-- | qualified_name '*'
-- | ONLY qualified_name
-- | ONLY '(' qualified_name ')'
-- @
data RelationExpr
  = SimpleRelationExpr
      QualifiedName
      -- ^ Name.
      Bool
      -- ^ Is asterisk present?
  | OnlyRelationExpr
      QualifiedName
      -- ^ Name.
      Bool
      -- ^ Are parentheses present?
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- relation_expr_opt_alias:
--   | relation_expr
--   | relation_expr ColId
--   | relation_expr AS ColId
-- @
data RelationExprOptAlias = RelationExprOptAlias RelationExpr (Maybe (Bool, ColId))
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- tablesample_clause:
--   | TABLESAMPLE func_name '(' expr_list ')' opt_repeatable_clause
-- @
data TablesampleClause = TablesampleClause FuncName ExprList (Maybe RepeatableClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_repeatable_clause:
--   | REPEATABLE '(' a_expr ')'
--   | EMPTY
-- @
type RepeatableClause = AExpr

-- |
-- ==== References
-- @
-- func_table:
--   | func_expr_windowless opt_ordinality
--   | ROWS FROM '(' rowsfrom_list ')' opt_ordinality
-- @
data FuncTable
  = FuncExprFuncTable FuncExprWindowless OptOrdinality
  | RowsFromFuncTable RowsfromList OptOrdinality
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- rowsfrom_item:
--   | func_expr_windowless opt_col_def_list
-- @
data RowsfromItem = RowsfromItem FuncExprWindowless (Maybe ColDefList)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- rowsfrom_list:
--   | rowsfrom_item
--   | rowsfrom_list ',' rowsfrom_item
-- @
type RowsfromList = NonEmpty RowsfromItem

-- |
-- ==== References
-- @
-- opt_col_def_list:
--   | AS '(' TableFuncElementList ')'
--   | EMPTY
-- @
type ColDefList = TableFuncElementList

-- |
-- ==== References
-- @
-- opt_ordinality:
--   | WITH_LA ORDINALITY
--   | EMPTY
-- @
type OptOrdinality = Bool

-- |
-- ==== References
-- @
-- TableFuncElementList:
--   | TableFuncElement
--   | TableFuncElementList ',' TableFuncElement
-- @
type TableFuncElementList = NonEmpty TableFuncElement

-- |
-- ==== References
-- @
-- TableFuncElement:
--   | ColId Typename opt_collate_clause
-- @
data TableFuncElement = TableFuncElement ColId Typename (Maybe CollateClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_collate_clause:
--   | COLLATE any_name
--   | EMPTY
-- @
type CollateClause = AnyName

-- |
-- ==== References
-- @
-- alias_clause:
--   |  AS ColId '(' name_list ')'
--   |  AS ColId
--   |  ColId '(' name_list ')'
--   |  ColId
-- @
data AliasClause = AliasClause Bool ColId (Maybe NameList)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_alias_clause:
--   | alias_clause
--   | AS '(' TableFuncElementList ')'
--   | AS ColId '(' TableFuncElementList ')'
--   | ColId '(' TableFuncElementList ')'
--   | EMPTY
-- @
data FuncAliasClause
  = AliasFuncAliasClause AliasClause
  | AsFuncAliasClause TableFuncElementList
  | AsColIdFuncAliasClause ColId TableFuncElementList
  | ColIdFuncAliasClause ColId TableFuncElementList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- | '(' joined_table ')'
-- | table_ref CROSS JOIN table_ref
-- | table_ref join_type JOIN table_ref join_qual
-- | table_ref JOIN table_ref join_qual
-- | table_ref NATURAL join_type JOIN table_ref
-- | table_ref NATURAL JOIN table_ref
--
-- The options are covered by the `JoinMeth` type.
-- @
data JoinedTable
  = InParensJoinedTable JoinedTable
  | MethJoinedTable JoinMeth TableRef TableRef
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- | table_ref CROSS JOIN table_ref
-- | table_ref join_type JOIN table_ref join_qual
-- | table_ref JOIN table_ref join_qual
-- | table_ref NATURAL join_type JOIN table_ref
-- | table_ref NATURAL JOIN table_ref
-- @
data JoinMeth
  = CrossJoinMeth
  | QualJoinMeth (Maybe JoinType) JoinQual
  | NaturalJoinMeth (Maybe JoinType)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- | FULL join_outer
-- | LEFT join_outer
-- | RIGHT join_outer
-- | INNER_P
-- @
data JoinType
  = FullJoinType Bool
  | LeftJoinType Bool
  | RightJoinType Bool
  | InnerJoinType
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- join_qual:
--   |  USING '(' name_list ')'
--   |  ON a_expr
-- @
data JoinQual
  = UsingJoinQual (NonEmpty Ident)
  | OnJoinQual AExpr
  deriving (Show, Generic, Eq, Ord)

-- * Where

type WhereClause = AExpr

-- |
-- ==== References
-- @
-- | WHERE a_expr
-- | WHERE CURRENT_P OF cursor_name
-- | /*EMPTY*/
-- @
data WhereOrCurrentClause
  = ExprWhereOrCurrentClause AExpr
  | CursorWhereOrCurrentClause CursorName
  deriving (Show, Generic, Eq, Ord)

-- * Expression

type ExprList = NonEmpty AExpr

-- |
-- ==== References
-- @
-- a_expr:
--   | c_expr
--   | a_expr TYPECAST Typename
--   | a_expr COLLATE any_name
--   | a_expr AT TIME ZONE a_expr
--   | '+' a_expr
--   | '-' a_expr
--   | a_expr '+' a_expr
--   | a_expr '-' a_expr
--   | a_expr '*' a_expr
--   | a_expr '/' a_expr
--   | a_expr '%' a_expr
--   | a_expr '^' a_expr
--   | a_expr '<' a_expr
--   | a_expr '>' a_expr
--   | a_expr '=' a_expr
--   | a_expr LESS_EQUALS a_expr
--   | a_expr GREATER_EQUALS a_expr
--   | a_expr NOT_EQUALS a_expr
--   | a_expr qual_Op a_expr
--   | qual_Op a_expr
--   | a_expr qual_Op
--   | a_expr AND a_expr
--   | a_expr OR a_expr
--   | NOT a_expr
--   | NOT_LA a_expr
--   | a_expr LIKE a_expr
--   | a_expr LIKE a_expr ESCAPE a_expr
--   | a_expr NOT_LA LIKE a_expr
--   | a_expr NOT_LA LIKE a_expr ESCAPE a_expr
--   | a_expr ILIKE a_expr
--   | a_expr ILIKE a_expr ESCAPE a_expr
--   | a_expr NOT_LA ILIKE a_expr
--   | a_expr NOT_LA ILIKE a_expr ESCAPE a_expr
--   | a_expr SIMILAR TO a_expr
--   | a_expr SIMILAR TO a_expr ESCAPE a_expr
--   | a_expr NOT_LA SIMILAR TO a_expr
--   | a_expr NOT_LA SIMILAR TO a_expr ESCAPE a_expr
--   | a_expr IS NULL_P
--   | a_expr ISNULL
--   | a_expr IS NOT NULL_P
--   | a_expr NOTNULL
--   | row OVERLAPS row
--   | a_expr IS TRUE_P
--   | a_expr IS NOT TRUE_P
--   | a_expr IS FALSE_P
--   | a_expr IS NOT FALSE_P
--   | a_expr IS UNKNOWN
--   | a_expr IS NOT UNKNOWN
--   | a_expr IS DISTINCT FROM a_expr
--   | a_expr IS NOT DISTINCT FROM a_expr
--   | a_expr IS OF '(' type_list ')'
--   | a_expr IS NOT OF '(' type_list ')'
--   | a_expr BETWEEN opt_asymmetric b_expr AND a_expr
--   | a_expr NOT_LA BETWEEN opt_asymmetric b_expr AND a_expr
--   | a_expr BETWEEN SYMMETRIC b_expr AND a_expr
--   | a_expr NOT_LA BETWEEN SYMMETRIC b_expr AND a_expr
--   | a_expr IN_P in_expr
--   | a_expr NOT_LA IN_P in_expr
--   | a_expr subquery_Op sub_type select_with_parens
--   | a_expr subquery_Op sub_type '(' a_expr ')'
--   | UNIQUE select_with_parens
--   | a_expr IS DOCUMENT_P
--   | a_expr IS NOT DOCUMENT_P
--   | DEFAULT
-- @
data AExpr
  = CExprAExpr CExpr
  | TypecastAExpr AExpr Typename
  | CollateAExpr AExpr AnyName
  | AtTimeZoneAExpr AExpr AExpr
  | PlusAExpr AExpr
  | MinusAExpr AExpr
  | SymbolicBinOpAExpr AExpr SymbolicExprBinOp AExpr
  | PrefixQualOpAExpr QualOp AExpr
  | SuffixQualOpAExpr AExpr QualOp
  | AndAExpr AExpr AExpr
  | OrAExpr AExpr AExpr
  | NotAExpr AExpr
  | VerbalExprBinOpAExpr AExpr Bool VerbalExprBinOp AExpr (Maybe AExpr)
  | ReversableOpAExpr AExpr Bool AExprReversableOp
  | IsnullAExpr AExpr
  | NotnullAExpr AExpr
  | OverlapsAExpr Row Row
  | SubqueryAExpr AExpr SubqueryOp SubType (Either SelectWithParens AExpr)
  | UniqueAExpr SelectWithParens
  | DefaultAExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- b_expr:
--   | c_expr
--   | b_expr TYPECAST Typename
--   | '+' b_expr
--   | '-' b_expr
--   | b_expr '+' b_expr
--   | b_expr '-' b_expr
--   | b_expr '*' b_expr
--   | b_expr '/' b_expr
--   | b_expr '%' b_expr
--   | b_expr '^' b_expr
--   | b_expr '<' b_expr
--   | b_expr '>' b_expr
--   | b_expr '=' b_expr
--   | b_expr LESS_EQUALS b_expr
--   | b_expr GREATER_EQUALS b_expr
--   | b_expr NOT_EQUALS b_expr
--   | b_expr qual_Op b_expr
--   | qual_Op b_expr
--   | b_expr qual_Op
--   | b_expr IS DISTINCT FROM b_expr
--   | b_expr IS NOT DISTINCT FROM b_expr
--   | b_expr IS OF '(' type_list ')'
--   | b_expr IS NOT OF '(' type_list ')'
--   | b_expr IS DOCUMENT_P
--   | b_expr IS NOT DOCUMENT_P
-- @
data BExpr
  = CExprBExpr CExpr
  | TypecastBExpr BExpr Typename
  | PlusBExpr BExpr
  | MinusBExpr BExpr
  | SymbolicBinOpBExpr BExpr SymbolicExprBinOp BExpr
  | QualOpBExpr QualOp BExpr
  | IsOpBExpr BExpr Bool BExprIsOp
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- c_expr:
--   | columnref
--   | AexprConst
--   | PARAM opt_indirection
--   | '(' a_expr ')' opt_indirection
--   | case_expr
--   | func_expr
--   | select_with_parens
--   | select_with_parens indirection
--   | EXISTS select_with_parens
--   | ARRAY select_with_parens
--   | ARRAY array_expr
--   | explicit_row
--   | implicit_row
--   | GROUPING '(' expr_list ')'
-- @
data CExpr
  = ColumnrefCExpr Columnref
  | AexprConstCExpr AexprConst
  | ParamCExpr Int (Maybe Indirection)
  | InParensCExpr AExpr (Maybe Indirection)
  | CaseCExpr CaseExpr
  | FuncCExpr FuncExpr
  | SelectWithParensCExpr SelectWithParens (Maybe Indirection)
  | ExistsCExpr SelectWithParens
  | ArrayCExpr (Either SelectWithParens ArrayExpr)
  | ExplicitRowCExpr ExplicitRow
  | ImplicitRowCExpr ImplicitRow
  | GroupingCExpr ExprList
  deriving (Show, Generic, Eq, Ord)

-- **

-- |
-- ==== References
-- @
-- in_expr:
--   | select_with_parens
--   | '(' expr_list ')'
-- @
data InExpr
  = SelectInExpr SelectWithParens
  | ExprListInExpr ExprList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- sub_type:
--   | ANY
--   | SOME
--   | ALL
-- @
data SubType = AnySubType | SomeSubType | AllSubType
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

-- |
-- ==== References
-- @
-- array_expr:
--   | '[' expr_list ']'
--   | '[' array_expr_list ']'
--   | '[' ']'
-- @
data ArrayExpr
  = ExprListArrayExpr ExprList
  | ArrayExprListArrayExpr ArrayExprList
  | EmptyArrayExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- array_expr_list:
--   | array_expr
--   | array_expr_list ',' array_expr
-- @
type ArrayExprList = NonEmpty ArrayExpr

-- |
-- ==== References
-- @
-- row:
--   | ROW '(' expr_list ')'
--   | ROW '(' ')'
--   | '(' expr_list ',' a_expr ')'
-- @
data Row
  = ExplicitRowRow ExplicitRow
  | ImplicitRowRow ImplicitRow
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- explicit_row:
--   | ROW '(' expr_list ')'
--   | ROW '(' ')'
-- @
type ExplicitRow = Maybe ExprList

-- |
-- ==== References
-- @
-- implicit_row:
--   | '(' expr_list ',' a_expr ')'
-- @
data ImplicitRow = ImplicitRow ExprList AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_expr:
--   | func_application within_group_clause filter_clause over_clause
--   | func_expr_common_subexpr
-- @
data FuncExpr
  = ApplicationFuncExpr FuncApplication (Maybe WithinGroupClause) (Maybe FilterClause) (Maybe OverClause)
  | SubexprFuncExpr FuncExprCommonSubexpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_expr_windowless:
--   | func_application
--   | func_expr_common_subexpr
-- @
data FuncExprWindowless
  = ApplicationFuncExprWindowless FuncApplication
  | CommonSubexprFuncExprWindowless FuncExprCommonSubexpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- within_group_clause:
--   | WITHIN GROUP_P '(' sort_clause ')'
--   | EMPTY
-- @
type WithinGroupClause = SortClause

-- |
-- ==== References
-- @
-- filter_clause:
--   | FILTER '(' WHERE a_expr ')'
--   | EMPTY
-- @
type FilterClause = AExpr

-- |
-- ==== References
-- @
-- over_clause:
--   | OVER window_specification
--   | OVER ColId
--   | EMPTY
-- @
data OverClause
  = WindowOverClause WindowSpecification
  | ColIdOverClause ColId
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_expr_common_subexpr:
--   | COLLATION FOR '(' a_expr ')'
--   | CURRENT_DATE
--   | CURRENT_TIME
--   | CURRENT_TIME '(' Iconst ')'
--   | CURRENT_TIMESTAMP
--   | CURRENT_TIMESTAMP '(' Iconst ')'
--   | LOCALTIME
--   | LOCALTIME '(' Iconst ')'
--   | LOCALTIMESTAMP
--   | LOCALTIMESTAMP '(' Iconst ')'
--   | CURRENT_ROLE
--   | CURRENT_USER
--   | SESSION_USER
--   | USER
--   | CURRENT_CATALOG
--   | CURRENT_SCHEMA
--   | CAST '(' a_expr AS Typename ')'
--   | EXTRACT '(' extract_list ')'
--   | OVERLAY '(' overlay_list ')'
--   | POSITION '(' position_list ')'
--   | SUBSTRING '(' substr_list ')'
--   | TREAT '(' a_expr AS Typename ')'
--   | TRIM '(' BOTH trim_list ')'
--   | TRIM '(' LEADING trim_list ')'
--   | TRIM '(' TRAILING trim_list ')'
--   | TRIM '(' trim_list ')'
--   | NULLIF '(' a_expr ',' a_expr ')'
--   | COALESCE '(' expr_list ')'
--   | GREATEST '(' expr_list ')'
--   | LEAST '(' expr_list ')'
--   | XMLCONCAT '(' expr_list ')'
--   | XMLELEMENT '(' NAME_P ColLabel ')'
--   | XMLELEMENT '(' NAME_P ColLabel ',' xml_attributes ')'
--   | XMLELEMENT '(' NAME_P ColLabel ',' expr_list ')'
--   | XMLELEMENT '(' NAME_P ColLabel ',' xml_attributes ',' expr_list ')'
--   | XMLEXISTS '(' c_expr xmlexists_argument ')'
--   | XMLFOREST '(' xml_attribute_list ')'
--   | XMLPARSE '(' document_or_content a_expr xml_whitespace_option ')'
--   | XMLPI '(' NAME_P ColLabel ')'
--   | XMLPI '(' NAME_P ColLabel ',' a_expr ')'
--   | XMLROOT '(' a_expr ',' xml_root_version opt_xml_root_standalone ')'
--   | XMLSERIALIZE '(' document_or_content a_expr AS SimpleTypename ')'
--
-- TODO: Implement the XML cases
-- @
data FuncExprCommonSubexpr
  = CollationForFuncExprCommonSubexpr AExpr
  | CurrentDateFuncExprCommonSubexpr
  | CurrentTimeFuncExprCommonSubexpr (Maybe Int64)
  | CurrentTimestampFuncExprCommonSubexpr (Maybe Int64)
  | LocalTimeFuncExprCommonSubexpr (Maybe Int64)
  | LocalTimestampFuncExprCommonSubexpr (Maybe Int64)
  | CurrentRoleFuncExprCommonSubexpr
  | CurrentUserFuncExprCommonSubexpr
  | SessionUserFuncExprCommonSubexpr
  | UserFuncExprCommonSubexpr
  | CurrentCatalogFuncExprCommonSubexpr
  | CurrentSchemaFuncExprCommonSubexpr
  | CastFuncExprCommonSubexpr AExpr Typename
  | ExtractFuncExprCommonSubexpr (Maybe ExtractList)
  | OverlayFuncExprCommonSubexpr OverlayList
  | PositionFuncExprCommonSubexpr (Maybe PositionList)
  | SubstringFuncExprCommonSubexpr (Maybe SubstrList)
  | TreatFuncExprCommonSubexpr AExpr Typename
  | TrimFuncExprCommonSubexpr (Maybe TrimModifier) TrimList
  | NullIfFuncExprCommonSubexpr AExpr AExpr
  | CoalesceFuncExprCommonSubexpr ExprList
  | GreatestFuncExprCommonSubexpr ExprList
  | LeastFuncExprCommonSubexpr ExprList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- extract_list:
--   | extract_arg FROM a_expr
--   | EMPTY
-- @
data ExtractList = ExtractList ExtractArg AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- extract_arg:
--   | IDENT
--   | YEAR_P
--   | MONTH_P
--   | DAY_P
--   | HOUR_P
--   | MINUTE_P
--   | SECOND_P
--   | Sconst
-- @
data ExtractArg
  = IdentExtractArg Ident
  | YearExtractArg
  | MonthExtractArg
  | DayExtractArg
  | HourExtractArg
  | MinuteExtractArg
  | SecondExtractArg
  | SconstExtractArg Sconst
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- overlay_list:
--   | a_expr overlay_placing substr_from substr_for
--   | a_expr overlay_placing substr_from
-- @
data OverlayList = OverlayList AExpr OverlayPlacing SubstrFrom (Maybe SubstrFor)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- overlay_placing:
--   | PLACING a_expr
-- @
type OverlayPlacing = AExpr

-- |
-- ==== References
-- @
-- position_list:
--   | b_expr IN_P b_expr
--   | EMPTY
-- @
data PositionList = PositionList BExpr BExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- substr_list:
--   | a_expr substr_from substr_for
--   | a_expr substr_for substr_from
--   | a_expr substr_from
--   | a_expr substr_for
--   | expr_list
--   | EMPTY
-- @
data SubstrList
  = ExprSubstrList AExpr SubstrListFromFor
  | ExprListSubstrList ExprList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
--   | a_expr substr_from substr_for
--   | a_expr substr_for substr_from
--   | a_expr substr_from
--   | a_expr substr_for
-- @
data SubstrListFromFor
  = FromForSubstrListFromFor SubstrFrom SubstrFor
  | ForFromSubstrListFromFor SubstrFor SubstrFrom
  | FromSubstrListFromFor SubstrFrom
  | ForSubstrListFromFor SubstrFor
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- substr_from:
--   | FROM a_expr
-- @
type SubstrFrom = AExpr

-- |
-- ==== References
-- @
-- substr_for:
--   | FOR a_expr
-- @
type SubstrFor = AExpr

-- |
-- ==== References
-- @
--   | TRIM '(' BOTH trim_list ')'
--   | TRIM '(' LEADING trim_list ')'
--   | TRIM '(' TRAILING trim_list ')'
-- @
data TrimModifier = BothTrimModifier | LeadingTrimModifier | TrailingTrimModifier
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

-- |
-- ==== References
-- @
-- trim_list:
--   | a_expr FROM expr_list
--   | FROM expr_list
--   | expr_list
-- @
data TrimList
  = ExprFromExprListTrimList AExpr ExprList
  | FromExprListTrimList ExprList
  | ExprListTrimList ExprList
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- case_expr:
--   | CASE case_arg when_clause_list case_default END_P
-- @
data CaseExpr = CaseExpr (Maybe CaseArg) WhenClauseList (Maybe CaseDefault)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- case_arg:
--   | a_expr
--   | EMPTY
-- @
type CaseArg = AExpr

-- |
-- ==== References
-- @
-- when_clause_list:
--   | when_clause
--   | when_clause_list when_clause
-- @
type WhenClauseList = NonEmpty WhenClause

-- |
-- ==== References
-- @
-- case_default:
--   | ELSE a_expr
--   | EMPTY
-- @
type CaseDefault = AExpr

-- |
-- ==== References
-- @
-- when_clause:
--   |  WHEN a_expr THEN a_expr
-- @
data WhenClause = WhenClause AExpr AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_application:
--   |  func_name '(' ')'
--   |  func_name '(' func_arg_list opt_sort_clause ')'
--   |  func_name '(' VARIADIC func_arg_expr opt_sort_clause ')'
--   |  func_name '(' func_arg_list ',' VARIADIC func_arg_expr opt_sort_clause ')'
--   |  func_name '(' ALL func_arg_list opt_sort_clause ')'
--   |  func_name '(' DISTINCT func_arg_list opt_sort_clause ')'
--   |  func_name '(' '*' ')'
-- @
data FuncApplication = FuncApplication FuncName (Maybe FuncApplicationParams)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_application:
--   |  func_name '(' ')'
--   |  func_name '(' func_arg_list opt_sort_clause ')'
--   |  func_name '(' VARIADIC func_arg_expr opt_sort_clause ')'
--   |  func_name '(' func_arg_list ',' VARIADIC func_arg_expr opt_sort_clause ')'
--   |  func_name '(' ALL func_arg_list opt_sort_clause ')'
--   |  func_name '(' DISTINCT func_arg_list opt_sort_clause ')'
--   |  func_name '(' '*' ')'
-- @
data FuncApplicationParams
  = NormalFuncApplicationParams (Maybe Bool) (NonEmpty FuncArgExpr) (Maybe SortClause)
  | VariadicFuncApplicationParams (Maybe (NonEmpty FuncArgExpr)) FuncArgExpr (Maybe SortClause)
  | StarFuncApplicationParams
  deriving (Show, Generic, Eq, Ord)

data FuncArgExpr
  = ExprFuncArgExpr AExpr
  | ColonEqualsFuncArgExpr Ident AExpr
  | EqualsGreaterFuncArgExpr Ident AExpr
  deriving (Show, Generic, Eq, Ord)

-- * Constants

type Sconst = Text

type Iconst = Int64

type Fconst = Double

type Bconst = Text

type Xconst = Text

-- |
-- AexprConst:
--   |  Iconst
--   |  FCONST
--   |  Sconst
--   |  BCONST
--   |  XCONST
--   |  func_name Sconst
--   |  func_name '(' func_arg_list opt_sort_clause ')' Sconst
--   |  ConstTypename Sconst
--   |  ConstInterval Sconst opt_interval
--   |  ConstInterval '(' Iconst ')' Sconst
--   |  TRUE_P
--   |  FALSE_P
--   |  NULL_P
data AexprConst
  = IAexprConst Iconst
  | FAexprConst Fconst
  | SAexprConst Sconst
  | BAexprConst Bconst
  | XAexprConst Xconst
  | FuncAexprConst FuncName (Maybe FuncConstArgs) Sconst
  | ConstTypenameAexprConst ConstTypename Sconst
  | StringIntervalAexprConst Sconst (Maybe Interval)
  | IntIntervalAexprConst Iconst Sconst
  | BoolAexprConst Bool
  | NullAexprConst
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
--   |  func_name '(' func_arg_list opt_sort_clause ')' Sconst
-- @
data FuncConstArgs = FuncConstArgs (NonEmpty FuncArgExpr) (Maybe SortClause)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- ConstTypename:
--   | Numeric
--   | ConstBit
--   | ConstCharacter
--   | ConstDatetime
-- @
data ConstTypename
  = NumericConstTypename Numeric
  | ConstBitConstTypename ConstBit
  | ConstCharacterConstTypename ConstCharacter
  | ConstDatetimeConstTypename ConstDatetime
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- Numeric:
--   | INT_P
--   | INTEGER
--   | SMALLINT
--   | BIGINT
--   | REAL
--   | FLOAT_P opt_float
--   | DOUBLE_P PRECISION
--   | DECIMAL_P opt_type_modifiers
--   | DEC opt_type_modifiers
--   | NUMERIC opt_type_modifiers
--   | BOOLEAN_P
-- opt_float:
--   | '(' Iconst ')'
--   | EMPTY
-- opt_type_modifiers:
--   | '(' expr_list ')'
--   | EMPTY
-- @
data Numeric
  = IntNumeric
  | IntegerNumeric
  | SmallintNumeric
  | BigintNumeric
  | RealNumeric
  | FloatNumeric (Maybe Int64)
  | DoublePrecisionNumeric
  | DecimalNumeric (Maybe TypeModifiers)
  | DecNumeric (Maybe TypeModifiers)
  | NumericNumeric (Maybe TypeModifiers)
  | BooleanNumeric
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- Bit:
--   | BitWithLength
--   | BitWithoutLength
-- ConstBit:
--   | BitWithLength
--   | BitWithoutLength
-- BitWithLength:
--   | BIT opt_varying '(' expr_list ')'
-- BitWithoutLength:
--   | BIT opt_varying
-- @
data Bit = Bit OptVarying (Maybe ExprList)
  deriving (Show, Generic, Eq, Ord)

type ConstBit = Bit

-- |
-- ==== References
-- @
-- opt_varying:
--   | VARYING
--   | EMPTY
-- @
type OptVarying = Bool

-- |
-- ==== References
-- @
-- Character:
--   | CharacterWithLength
--   | CharacterWithoutLength
-- ConstCharacter:
--   | CharacterWithLength
--   | CharacterWithoutLength
-- CharacterWithLength:
--   | character '(' Iconst ')'
-- CharacterWithoutLength:
--   | character
-- @
data ConstCharacter = ConstCharacter Character (Maybe Int64)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- character:
--   | CHARACTER opt_varying
--   | CHAR_P opt_varying
--   | VARCHAR
--   | NATIONAL CHARACTER opt_varying
--   | NATIONAL CHAR_P opt_varying
--   | NCHAR opt_varying
-- @
data Character
  = CharacterCharacter OptVarying
  | CharCharacter OptVarying
  | VarcharCharacter
  | NationalCharacterCharacter OptVarying
  | NationalCharCharacter OptVarying
  | NcharCharacter OptVarying
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- ConstDatetime:
--   | TIMESTAMP '(' Iconst ')' opt_timezone
--   | TIMESTAMP opt_timezone
--   | TIME '(' Iconst ')' opt_timezone
--   | TIME opt_timezone
-- @
data ConstDatetime
  = TimestampConstDatetime (Maybe Int64) (Maybe Timezone)
  | TimeConstDatetime (Maybe Int64) (Maybe Timezone)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_timezone:
--   | WITH_LA TIME ZONE
--   | WITHOUT TIME ZONE
--   | EMPTY
-- @
type Timezone = Bool

-- |
-- ==== References
-- @
-- opt_interval:
--   | YEAR_P
--   | MONTH_P
--   | DAY_P
--   | HOUR_P
--   | MINUTE_P
--   | interval_second
--   | YEAR_P TO MONTH_P
--   | DAY_P TO HOUR_P
--   | DAY_P TO MINUTE_P
--   | DAY_P TO interval_second
--   | HOUR_P TO MINUTE_P
--   | HOUR_P TO interval_second
--   | MINUTE_P TO interval_second
--   | EMPTY
-- @
data Interval
  = YearInterval
  | MonthInterval
  | DayInterval
  | HourInterval
  | MinuteInterval
  | SecondInterval IntervalSecond
  | YearToMonthInterval
  | DayToHourInterval
  | DayToMinuteInterval
  | DayToSecondInterval IntervalSecond
  | HourToMinuteInterval
  | HourToSecondInterval IntervalSecond
  | MinuteToSecondInterval IntervalSecond
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- interval_second:
--   | SECOND_P
--   | SECOND_P '(' Iconst ')'
-- @
type IntervalSecond = Maybe Int64

-- * Names & References

-- |
-- ==== References
-- @
-- IDENT
-- @
data Ident = QuotedIdent Text | UnquotedIdent Text
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- ColId:
--   | IDENT
--   | unreserved_keyword
--   | col_name_keyword
-- @
type ColId = Ident

-- |
-- ==== References
-- @
-- ColLabel:
--   | IDENT
--   | unreserved_keyword
--   | col_name_keyword
--   | type_func_name_keyword
--   | reserved_keyword
-- @
type ColLabel = Ident

-- |
-- ==== References
-- @
-- name:
--   | ColId
-- @
type Name = ColId

-- |
-- ==== References
-- @
-- name_list:
--   | name
--   | name_list ',' name
-- @
type NameList = NonEmpty Name

-- |
-- ==== References
-- @
-- cursor_name:
--   | name
-- @
type CursorName = Name

-- |
-- ==== References
-- @
-- columnref:
--   | ColId
--   | ColId indirection
-- @
data Columnref = Columnref ColId (Maybe Indirection)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- any_name:
--   | ColId
--   | ColId attrs
-- @
data AnyName = AnyName ColId (Maybe Attrs)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- func_name:
--   | type_function_name
--   | ColId indirection
-- @
data FuncName
  = TypeFuncName TypeFunctionName
  | IndirectedFuncName ColId Indirection
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- type_function_name:
--   | IDENT
--   | unreserved_keyword
--   | type_func_name_keyword
-- @
type TypeFunctionName = Ident

-- |
-- ==== References
-- @
-- columnref:
--   | ColId
--   | ColId indirection
-- qualified_name:
--   | ColId
--   | ColId indirection
-- @
data QualifiedName
  = SimpleQualifiedName Ident
  | IndirectedQualifiedName Ident Indirection
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- indirection:
--   |  indirection_el
--   |  indirection indirection_el
-- @
type Indirection = NonEmpty IndirectionEl

-- |
-- ==== References
-- @
-- indirection_el:
--   |  '.' attr_name
--   |  '.' '*'
--   |  '[' a_expr ']'
--   |  '[' opt_slice_bound ':' opt_slice_bound ']'
-- opt_slice_bound:
--   |  a_expr
--   |  EMPTY
-- @
data IndirectionEl
  = AttrNameIndirectionEl Ident
  | AllIndirectionEl
  | ExprIndirectionEl AExpr
  | SliceIndirectionEl (Maybe AExpr) (Maybe AExpr)
  deriving (Show, Generic, Eq, Ord)

-- * Types

-- |
-- Typename definition extended with custom question-marks for nullability specification.
--
-- To match the standard Postgres syntax simply interpret their presence as a parsing error.
--
-- ==== References
-- @
-- Typename:
--   | SimpleTypename opt_array_bounds
--   | SETOF SimpleTypename opt_array_bounds
--   | SimpleTypename ARRAY '[' Iconst ']'
--   | SETOF SimpleTypename ARRAY '[' Iconst ']'
--   | SimpleTypename ARRAY
--   | SETOF SimpleTypename ARRAY
-- @
data Typename
  = Typename
      Bool
      -- ^ SETOF
      SimpleTypename
      Bool
      -- ^ Question mark
      (Maybe (TypenameArrayDimensions, Bool))
      -- ^ Array dimensions possibly followed by a question mark
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- Part of the Typename specification responsible for the choice between the following:
--   | opt_array_bounds
--   | ARRAY '[' Iconst ']'
--   | ARRAY
-- @
data TypenameArrayDimensions
  = BoundsTypenameArrayDimensions ArrayBounds
  | ExplicitTypenameArrayDimensions (Maybe Iconst)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_array_bounds:
--   | opt_array_bounds '[' ']'
--   | opt_array_bounds '[' Iconst ']'
--   | EMPTY
-- @
type ArrayBounds = NonEmpty (Maybe Iconst)

-- |
-- ==== References
-- @
-- SimpleTypename:
--   | GenericType
--   | Numeric
--   | Bit
--   | Character
--   | ConstDatetime
--   | ConstInterval opt_interval
--   | ConstInterval '(' Iconst ')'
-- ConstInterval:
--   | INTERVAL
-- @
data SimpleTypename
  = GenericTypeSimpleTypename GenericType
  | NumericSimpleTypename Numeric
  | BitSimpleTypename Bit
  | CharacterSimpleTypename Character
  | ConstDatetimeSimpleTypename ConstDatetime
  | ConstIntervalSimpleTypename (Either (Maybe Interval) Iconst)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- GenericType:
--   | type_function_name opt_type_modifiers
--   | type_function_name attrs opt_type_modifiers
-- @
data GenericType = GenericType TypeFunctionName (Maybe Attrs) (Maybe TypeModifiers)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- attrs:
--   | '.' attr_name
--   | attrs '.' attr_name
-- @
type Attrs = NonEmpty AttrName

-- |
-- ==== References
-- @
-- attr_name:
--   | ColLabel
-- @
type AttrName = ColLabel

-- |
-- ==== References
-- @
-- opt_type_modifiers:
--   | '(' expr_list ')'
--   | EMPTY
-- @
type TypeModifiers = ExprList

-- |
-- ==== References
-- @
-- type_list:
--   | Typename
--   | type_list ',' Typename
-- @
type TypeList = NonEmpty Typename

-- * Operators

-- |
-- ==== References
-- @
-- qual_Op:
--   | Op
--   | OPERATOR '(' any_operator ')'
-- @
data QualOp
  = OpQualOp Op
  | OperatorQualOp AnyOperator
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- qual_all_Op:
--   | all_Op
--   | OPERATOR '(' any_operator ')'
-- @
data QualAllOp
  = AllQualAllOp AllOp
  | AnyQualAllOp AnyOperator
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- The operator name is a sequence of up to NAMEDATALEN-1 (63 by default)
-- characters from the following list:
--
-- + - * / < > = ~ ! @ # % ^ & | ` ?
--
-- There are a few restrictions on your choice of name:
-- -- and /* cannot appear anywhere in an operator name,
-- since they will be taken as the start of a comment.
--
-- A multicharacter operator name cannot end in + or -,
-- unless the name also contains at least one of these characters:
--
-- ~ ! @ # % ^ & | ` ?
--
-- For example, @- is an allowed operator name, but *- is not.
-- This restriction allows PostgreSQL to parse SQL-compliant
-- commands without requiring spaces between tokens.
-- The use of => as an operator name is deprecated.
-- It may be disallowed altogether in a future release.
--
-- The operator != is mapped to <> on input,
-- so these two names are always equivalent.
-- @
type Op = Text

-- |
-- ==== References
-- @
-- any_operator:
--   | all_Op
--   | ColId '.' any_operator
-- @
data AnyOperator
  = AllOpAnyOperator AllOp
  | QualifiedAnyOperator ColId AnyOperator
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- all_Op:
--   | Op
--   | MathOp
-- @
data AllOp
  = OpAllOp Op
  | MathAllOp MathOp
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- MathOp:
--   | '+'
--   | '-'
--   | '*'
--   | '/'
--   | '%'
--   | '^'
--   | '<'
--   | '>'
--   | '='
--   | LESS_EQUALS
--   | GREATER_EQUALS
--   | NOT_EQUALS
-- @
data MathOp
  = PlusMathOp
  | MinusMathOp
  | AsteriskMathOp
  | SlashMathOp
  | PercentMathOp
  | ArrowUpMathOp
  | ArrowLeftMathOp
  | ArrowRightMathOp
  | EqualsMathOp
  | LessEqualsMathOp
  | GreaterEqualsMathOp
  | ArrowLeftArrowRightMathOp
  | ExclamationEqualsMathOp
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

data SymbolicExprBinOp
  = MathSymbolicExprBinOp MathOp
  | QualSymbolicExprBinOp QualOp
  deriving (Show, Generic, Eq, Ord)

data VerbalExprBinOp
  = LikeVerbalExprBinOp
  | IlikeVerbalExprBinOp
  | SimilarToVerbalExprBinOp
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

-- |
-- ==== References
-- @
--   | a_expr IS NULL_P
--   | a_expr IS TRUE_P
--   | a_expr IS FALSE_P
--   | a_expr IS UNKNOWN
--   | a_expr IS DISTINCT FROM a_expr
--   | a_expr IS OF '(' type_list ')'
--   | a_expr BETWEEN opt_asymmetric b_expr AND a_expr
--   | a_expr BETWEEN SYMMETRIC b_expr AND a_expr
--   | a_expr IN_P in_expr
--   | a_expr IS DOCUMENT_P
-- @
data AExprReversableOp
  = NullAExprReversableOp
  | TrueAExprReversableOp
  | FalseAExprReversableOp
  | UnknownAExprReversableOp
  | DistinctFromAExprReversableOp AExpr
  | OfAExprReversableOp TypeList
  | BetweenAExprReversableOp Bool BExpr AExpr
  | BetweenSymmetricAExprReversableOp BExpr AExpr
  | InAExprReversableOp InExpr
  | DocumentAExprReversableOp
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
--   | b_expr IS DISTINCT FROM b_expr
--   | b_expr IS NOT DISTINCT FROM b_expr
--   | b_expr IS OF '(' type_list ')'
--   | b_expr IS NOT OF '(' type_list ')'
--   | b_expr IS DOCUMENT_P
--   | b_expr IS NOT DOCUMENT_P
-- @
data BExprIsOp
  = DistinctFromBExprIsOp BExpr
  | OfBExprIsOp TypeList
  | DocumentBExprIsOp
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- subquery_Op:
--   | all_Op
--   | OPERATOR '(' any_operator ')'
--   | LIKE
--   | NOT_LA LIKE
--   | ILIKE
--   | NOT_LA ILIKE
-- @
data SubqueryOp
  = AllSubqueryOp AllOp
  | AnySubqueryOp AnyOperator
  | LikeSubqueryOp Bool
  | IlikeSubqueryOp Bool
  deriving (Show, Generic, Eq, Ord)

-- * Indexes

-- |
-- ==== References
-- @
-- index_params:
--   | index_elem
--   | index_params ',' index_elem
-- @
type IndexParams = NonEmpty IndexElem

-- |
-- ==== References
-- @
-- index_elem:
--   | ColId opt_collate opt_class opt_asc_desc opt_nulls_order
--   | func_expr_windowless opt_collate opt_class opt_asc_desc opt_nulls_order
--   | '(' a_expr ')' opt_collate opt_class opt_asc_desc opt_nulls_order
-- @
data IndexElem = IndexElem IndexElemDef (Maybe Collate) (Maybe Class) (Maybe AscDesc) (Maybe NullsOrder)
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
--   | ColId opt_collate opt_class opt_asc_desc opt_nulls_order
--   | func_expr_windowless opt_collate opt_class opt_asc_desc opt_nulls_order
--   | '(' a_expr ')' opt_collate opt_class opt_asc_desc opt_nulls_order
-- @
data IndexElemDef
  = IdIndexElemDef ColId
  | FuncIndexElemDef FuncExprWindowless
  | ExprIndexElemDef AExpr
  deriving (Show, Generic, Eq, Ord)

-- |
-- ==== References
-- @
-- opt_collate:
--   | COLLATE any_name
--   | EMPTY
-- @
type Collate = AnyName

-- |
-- ==== References
-- @
-- opt_class:
--   | any_name
--   | EMPTY
-- @
type Class = AnyName

-- |
-- ==== References
-- @
-- opt_asc_desc:
--   | ASC
--   | DESC
--   | EMPTY
-- @
data AscDesc = AscAscDesc | DescAscDesc
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)

-- |
-- ==== References
-- @
-- opt_nulls_order:
--   | NULLS_LA FIRST_P
--   | NULLS_LA LAST_P
--   | EMPTY
-- @
data NullsOrder = FirstNullsOrder | LastNullsOrder
  deriving (Show, Generic, Eq, Ord, Enum, Bounded)