mirror of
https://github.com/apache/datafusion-sqlparser-rs.git
synced 2025-07-08 01:15:00 +00:00
80 lines
2 KiB
Rust
80 lines
2 KiB
Rust
use std::str::Chars;
|
|
use std::iter::Peekable;
|
|
|
|
extern crate datafusion_sql;
|
|
|
|
use datafusion_sql::ansi::tokenizer::ANSISQLTokenizer;
|
|
use datafusion_sql::tokenizer::*;
|
|
use datafusion_sql::parser::*;
|
|
|
|
///
|
|
/// This example demonstrates building a custom ACME parser that extends the generic parser
|
|
/// by adding support for a factorial operator !!
|
|
///
|
|
|
|
#[derive(Debug,PartialEq)]
|
|
enum AcmeToken {
|
|
/// Factorial operator `!!`
|
|
Factorial
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
enum AcmeOperator {
|
|
Factorial
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
enum AcmeTokenizerError {
|
|
}
|
|
|
|
struct AcmeTokenizer {
|
|
generic: ANSISQLTokenizer
|
|
}
|
|
|
|
/// The ACME tokenizer looks for the factorial operator `!!` but delegates everything else
|
|
impl SQLTokenizer<AcmeToken> for AcmeTokenizer {
|
|
|
|
fn peek_token(&self, chars: &mut Peekable<Chars>) -> Result<Option<SQLToken<AcmeToken>>, TokenizerError<AcmeToken>> {
|
|
unimplemented!()
|
|
}
|
|
|
|
fn next_token(&self, chars: &mut Peekable<Chars>) -> Result<Option<SQLToken<AcmeToken>>, TokenizerError<AcmeToken>> {
|
|
match chars.peek() {
|
|
Some(&ch) => match ch {
|
|
'!' => {
|
|
chars.next(); // consume the first `!`
|
|
match chars.peek() {
|
|
Some(&ch) => match ch {
|
|
'!' => {
|
|
chars.next(); // consume the second `!`
|
|
Ok(Some(SQLToken::Custom(AcmeToken::Factorial)))
|
|
},
|
|
_ => Err(TokenizerError::UnexpectedChar(ch,Position::new(0,0)))
|
|
},
|
|
None => Ok(Some(SQLToken::Not))
|
|
}
|
|
},
|
|
_ => self.generic.next_token(chars)
|
|
}
|
|
_ => self.generic.next_token(chars)
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
fn main() {
|
|
|
|
let sql = "1 + !! 5 * 2";
|
|
|
|
let mut acme_tokenizer = AcmeTokenizer {
|
|
generic: ANSISQLTokenizer { }
|
|
};
|
|
|
|
let tokens = tokenize(&sql, &mut acme_tokenizer).unwrap();
|
|
|
|
println!("tokens = {:?}", tokens);
|
|
|
|
|
|
|
|
}
|