src/dialect/ansi.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;

/// A [`Dialect`] for [ANSI SQL](https://en.wikipedia.org/wiki/SQL:2011).
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct AnsiDialect {}

impl Dialect for AnsiDialect {
    /// The SQL standard uses double quotes for delimited identifiers.
    fn identifier_quote_style(&self, _identifier: &str) -> Option<char> {
        Some('"')
    }

    fn is_identifier_start(&self, ch: char) -> bool {
        ch.is_ascii_lowercase() || ch.is_ascii_uppercase()
    }

    fn is_identifier_part(&self, ch: char) -> bool {
        ch.is_ascii_lowercase() || ch.is_ascii_uppercase() || ch.is_ascii_digit() || ch == '_'
    }

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

    /// The SQL standard explicitly states that block comments nest.
    fn supports_nested_comments(&self) -> bool {
        true
    }
}