Provide included rules in the interface too

[hfhbd]

I want to include the rule compound_select_stmt from sql-psi:

set_stmt ::= SET host_variable ( COMMA host_variable ) * EQ ( set_setter_clause | {compound_select_stmt} )

This rule is not resolved in my bnf file, as expected, but it is later during composing:

fake set_stmt ::=  SET host_variable ( COMMA host_variable ) * EQ ( set_setter_clause | <<compoundSelectStmtRealExt <<compound_select_stmt_real_real>>>> )

set_stmt_real ::=  SET <<hostVariableExt host_variable_real>> ( COMMA <<hostVariableExt host_variable_real>> ) * EQ ( <<setSetterClauseExt set_setter_clause_real>> | <<compoundSelectStmtRealExt <<compound_select_stmt_real_real>>>> )

GrammarKit with Composer generates this interface:

public interface Db2SetStmt extends ... {
  @NotNull  List<Db2HostVariable> getHostVariableList();
  @Nullable Db2SetSetterClause getSetSetterClause();
}

Unfortunately, the compound_select_stmt is missing: @Nullable SqlCompoundSelectStmt getCompoundSelectStmt();

Sample: merge_key_selector from Hsql in sqldelight

merge_key_selector ::= KEY LP {column_name} RP

package app.cash.sqldelight.dialects.hsql.grammar.psi;

public interface HsqlMergeKeySelector extends SqlCompositeElement {

}

[hfhbd]

Workaround:

compound_select_stmt_internal ::= {compound_select_stmt} {
  implements = "com.alecstrong.sql.psi.core.psi.SqlCompoundSelectStmt"
  extends = "com.alecstrong.sql.psi.core.psi.impl.SqlCompoundSelectStmtImpl"
}

Can we generate this automatically?

[AlecKazakova]

hmmmm, thats an interesting idea.

Agree this would be amazing to solve. yea that workaround might work too. We should really get a test in this project so we could just make changes here and see if they work.

[hfhbd]

I already added some tests locally, will push it later.

[hfhbd]

I guess, we need to support left if I understand this rule correctly.
This grammar results into this tree:

compound_select_stmt_internal ::= {compound_select_stmt} {
  implements = "com.alecstrong.sql.psi.core.psi.SqlCompoundSelectStmt"
  extends = "com.alecstrong.sql.psi.core.psi.impl.SqlCompoundSelectStmtImpl"
}

Db2CompoundSelectStmtInternalImpl(COMPOUND_SELECT_STMT_INTERNAL): []
  SqlCompoundSelectStmtImpl(COMPOUND_SELECT_STMT): []
    Db2SelectStmtImpl(SELECT_STMT): []
      SqlResultColumnImpl(RESULT_COLUMN): [foo : [id, name [[rowid, oid, _rowid_]]]]
        SqlColumnExprImpl(COLUMN_EXPR): [foo : [id, name [[rowid, oid, _rowid_]]]]
          SqlColumnNameImpl(COLUMN_NAME): [foo : [id, name [[rowid, oid, _rowid_]]]]
      SqlJoinClauseImpl(JOIN_CLAUSE): []
        SqlTableOrSubqueryImpl(TABLE_OR_SUBQUERY): []
          SqlTableNameImpl(TABLE_NAME): []

So the Db2CompoundSelectStmtInternalImpl has another children: SqlCompoundSelectStmtImpl and calling getSelectStmtList (PsiTreeUtil.getChildrenOfTypeAsList(this, SqlSelectStmt.class)) does not work because the SqlSelecStmt is nested inside SqlCompoundSelectStmtImpl.

Simply adding left does not work:

1. Escape the rule name (left foo ::=) #72
2. Adding left results into wrong composed code:

fake left goodbye_internal ::=  <<goodbyeExt <<goodbye_real>>>> {
  implements = "com.example.psi.RootGoodbye"
  extends = "com.example.psi.impl.RootGoodbyeImpl"
}

left goodbye_internal_real ::=  <<goodbyeExt <<goodbye_real>>>> {
  elementType = left goodbye_internal
}

I think we could simple remove the fake and the second rule.