Details
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New Feature
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Status: Open
-
Minor
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Resolution: Unresolved
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1.29.0
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None
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None
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- mac-arm64
Description
Calcite currently supports [extending the parser](https://calcite.apache.org/docs/adapter.html#extending-the-parser) with `config.fmpp` that has sections statements including alter and drop.
I require the ability to introduce a custom `SELECT` like statement which requires adding adding an additional clause to the LeafQuery syntax in the `Parser.jj` file eg:
/**
* Parses a leaf in a query expression (SELECT, VALUES or TABLE).
*/
SqlNode LeafQuery(ExprContext exprContext) :
{
SqlNode e;
}
{
{
// ensure a query is legal in this context
checkQueryExpression(exprContext);
}
e = SqlSelect() { return e; }
|
<#-- Add methods to parse additional select statements here -->
<#list (parser.selectStatementParserMethods!default.parser.selectStatementParserMethods) as method>
e = ${method} { return e; }
|
</#list>
e = TableConstructor() { return e; }
|
e = ExplicitTable(getPos()) { return e; }
}
I would like to add a new section `selectStatementParserMethods` to the config eg:
# List of methods for parsing custom select statements. # Return type of method implementation should be 'SqlNode'. # Example: SqlSelect() selectStatementParserMethods: [ ]
Files required to be updated main codegen are:
- core/src/main/codegen/templates/Parser.jj
- core/src/main/codegen/default_config.fmpp