databricks.rs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

use crate::dialect::{Dialect, Precedence};
use crate::parser::{Parser, ParserError};
use crate::tokenizer::Token;

/// A [`Dialect`] for [Databricks SQL](https://www.databricks.com/)
///
/// See <https://docs.databricks.com/en/sql/language-manual/index.html>.
#[derive(Debug, Default)]
pub struct DatabricksDialect;

impl Dialect for DatabricksDialect {
    // see https://docs.databricks.com/en/sql/language-manual/sql-ref-identifiers.html

    fn is_delimited_identifier_start(&self, ch: char) -> bool {
        matches!(ch, '`')
    }

    fn is_identifier_start(&self, ch: char) -> bool {
        matches!(ch, 'a'..='z' | 'A'..='Z' | '_')
    }

    fn is_identifier_part(&self, ch: char) -> bool {
        matches!(ch, 'a'..='z' | 'A'..='Z' | '0'..='9' | '_')
    }

    fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {
        let token = parser.peek_token();
        // : is used for JSON path access
        match token.token {
            Token::Colon => Some(Ok(self.prec_value(Precedence::Period))),
            _ => None,
        }
    }

    fn supports_semi_structured_array_all_elements(&self) -> bool {
        true
    }

    fn supports_filter_during_aggregation(&self) -> bool {
        true
    }

    // https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-qry-select-groupby.html
    fn supports_group_by_expr(&self) -> bool {
        true
    }

    fn supports_lambda_functions(&self) -> bool {
        true
    }

    // https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-qry-select.html#syntax
    fn supports_select_wildcard_except(&self) -> bool {
        true
    }

    fn require_interval_qualifier(&self) -> bool {
        true
    }

    // See https://docs.databricks.com/en/sql/language-manual/functions/struct.html
    fn supports_struct_literal(&self) -> bool {
        true
    }

    // https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-syntax-comment
    fn supports_nested_comments(&self) -> bool {
        true
    }
}