Make Parser::maybe_parse pub

[Jesse-Bakker]

This method is useful for wrapping sqlparser's parser to parse custom syntax, falling back to the upstream implementation. For example:

enum CustomStatement {
    CreateCustom {
        or_replace: bool,
        thingy: String,
    },
    Statement(Statement),
}

fn parse_custom_create(parser: &mut Parser) -> Result<CustomStatement, ParserError> {
    if let Some(custom) = parser.maybe_parse(|parser| {
        let or_replace = parser.parse_keywords(&[Keyword::OR, Keyword::REPLACE]);
        parse_create_custom(or_replace)
    }) {
        Ok(custom)
    } else {
        Ok(CustomStatement::Statement(parser.parse_create()?))
    }
}

Without access to maybe_parse, this would not be possible be very inconvenient

[coveralls]

Pull Request Test Coverage Report for Build 10261971206

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.235%

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Totals
Change from base Build 10235939983:	0.0%
Covered Lines:	27472
Relevant Lines:	30786

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💛 - Coveralls

[iffyio]

LGTM! cc @alamb

[alamb]

🚀