Add HSQL support for generated clauses (#328)

Both HSQLDB and H2 support both variants of this clause. See http://hsqldb.org/doc/2.0/guide/databaseobjects-chapt.html#dbc_tables and https://h2database.com/html/grammar.html#column_definition respectively.

Support for this was previously implemented for Postgres in 52c847 (#295).

core/src/main/kotlin/com/alecstrong/sql/psi/core/hsql/hsql.bnf

@@ -48,6 +48,7 @@ column_constraint ::= [ CONSTRAINT {identifier} ] (
   NOT NULL {conflict_clause} |
   UNIQUE {conflict_clause} |
   {check_constraint} |
+  generated_clause |
   {default_constraint} |
   COLLATE {collation_name} |
   {foreign_key_clause}
@@ -86,4 +87,6 @@ interval_qualifier ::= start_field TO end_field | single_datetime_field
 start_field ::= non_second_primary_datetime_field [ '(' digit ')' ]
 end_field ::= non_second_primary_datetime_field | 'SECOND' [ '(' digit ')' ]
 single_datetime_field ::= non_second_primary_datetime_field [ '(' digit ')' ] | 'SECOND' [ '(' digit [ ',' digit ] ')' ]
-non_second_primary_datetime_field ::= 'YEAR' | 'MONTH' | 'DAY' | 'HOUR' | 'MINUTE'
+non_second_primary_datetime_field ::= 'YEAR' | 'MONTH' | 'DAY' | 'HOUR' | 'MINUTE'
+
+generated_clause ::= 'GENERATED' ( ( ('ALWAYS' | 'BY' 'DEFAULT') 'AS' 'IDENTITY' ) | ('ALWAYS' 'AS' <<expr '-1'>>) )

core/src/test/fixtures_hsql/column_types/Sample.s

@@ -41,5 +41,8 @@ CREATE TABLE all_types(
   some_interval2 INTERVAL YEAR(3),
   some_interval3 INTERVAL DAY(4) TO HOUR,
   some_interval4 INTERVAL MINUTE(4) TO SECOND(6),
-  some_interval5 INTERVAL SECOND(4,6)
+  some_interval5 INTERVAL SECOND(4,6),
+  some_always_generated_identity BIGINT GENERATED ALWAYS AS IDENTITY,
+  some_default_generated_identity BIGINT GENERATED BY DEFAULT AS IDENTITY,
+  some_always_generated_identity_primary_key BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY
 );