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use crate::parser::ast::*;
use crate::parser::error::ParseResult;
use crate::parser::state::Parser;
use crate::parser::token::Keyword;
use super::common::parse_comma_list;
use super::primary::parse_primary;
pub fn parse_expr(parser: &mut Parser) -> ParseResult<Expr> {
parse_pratt_expr(parser, 0)
}
fn parse_pratt_expr(parser: &mut Parser, min_bp: u8) -> ParseResult<Expr> {
parser.enter_recursion()?;
let res = (|| {
let mut left = parse_primary(parser)?;
loop {
if let Some(Token::Keyword(k)) = parser.peek() {
if *k == Keyword::Is {
let (l_bp, ()) = postfix_binding_power(k);
if l_bp < min_bp {
break;
}
let _ = parser.next();
let mut negated = false;
if parser.at_keyword(Keyword::Not) {
let _ = parser.next();
negated = true;
}
parser.expect_keyword(Keyword::Null)?;
left = if negated {
Expr::IsNotNull(Box::new(left))
} else {
Expr::IsNull(Box::new(left))
};
continue;
}
if *k == Keyword::Like {
let (l_bp, r_bp) = infix_binding_power_special("LIKE");
if l_bp < min_bp {
break;
}
let _ = parser.next();
let pattern = parse_pratt_expr(parser, r_bp)?;
let mut escape = None;
if parser.at_keyword(Keyword::Escape) {
let _ = parser.next();
escape = Some(Box::new(parse_pratt_expr(parser, r_bp)?));
}
left = Expr::Like {
expr: Box::new(left),
pattern: Box::new(pattern),
escape,
negated: false,
};
continue;
}
if *k == Keyword::Between {
let (l_bp, _) = infix_binding_power_special("BETWEEN");
if l_bp < min_bp {
break;
}
let _ = parser.next();
let low = parse_pratt_expr(parser, 6)?;
parser.expect_keyword(Keyword::And)?;
let high = parse_pratt_expr(parser, 6)?;
left = Expr::Between {
expr: Box::new(left),
low: Box::new(low),
high: Box::new(high),
negated: false,
};
continue;
}
if *k == Keyword::In {
let (l_bp, _) = infix_binding_power_special("IN");
if l_bp < min_bp {
break;
}
let _ = parser.next();
parser.expect_lparen()?;
if parser.at_keyword(Keyword::Select) {
let subquery = Box::new(
crate::parser::parse::statements::query::parse_select(parser)?,
);
parser.expect_rparen()?;
left = Expr::InSubquery {
expr: Box::new(left),
subquery,
negated: false,
};
} else {
let list = parse_comma_list(parser, super::parse_expr)?;
parser.expect_rparen()?;
left = Expr::InList {
expr: Box::new(left),
list,
negated: false,
};
}
continue;
}
if *k == Keyword::Not {
if let Some(Token::Keyword(k2)) = parser.peek_at(1) {
if *k2 == Keyword::Like {
let (l_bp, r_bp) = infix_binding_power_special("LIKE");
if l_bp < min_bp {
break;
}
let _ = parser.next();
let _ = parser.next();
let pattern = parse_pratt_expr(parser, r_bp)?;
let mut escape = None;
if parser.at_keyword(Keyword::Escape) {
let _ = parser.next();
escape = Some(Box::new(parse_pratt_expr(parser, r_bp)?));
}
left = Expr::Like {
expr: Box::new(left),
pattern: Box::new(pattern),
escape,
negated: true,
};
continue;
}
if *k2 == Keyword::Between {
let (l_bp, _) = infix_binding_power_special("BETWEEN");
if l_bp < min_bp {
break;
}
let _ = parser.next();
let _ = parser.next();
let low = parse_pratt_expr(parser, 6)?;
parser.expect_keyword(Keyword::And)?;
let high = parse_pratt_expr(parser, 6)?;
left = Expr::Between {
expr: Box::new(left),
low: Box::new(low),
high: Box::new(high),
negated: true,
};
continue;
}
if *k2 == Keyword::In {
let (l_bp, _) = infix_binding_power_special("IN");
if l_bp < min_bp {
break;
}
let _ = parser.next();
let _ = parser.next();
parser.expect_lparen()?;
if parser.at_keyword(Keyword::Select) {
let subquery = Box::new(
crate::parser::parse::statements::query::parse_select(parser)?,
);
parser.expect_rparen()?;
left = Expr::InSubquery {
expr: Box::new(left),
subquery,
negated: true,
};
} else {
let list = parse_comma_list(parser, super::parse_expr)?;
parser.expect_rparen()?;
left = Expr::InList {
expr: Box::new(left),
list,
negated: true,
};
}
continue;
}
}
}
}
let op = match parser.peek() {
Some(Token::Operator(op_str)) => match op_str.as_ref() {
"=" => BinaryOp::Eq,
"<>" | "!=" => BinaryOp::NotEq,
">" => BinaryOp::Gt,
"<" => BinaryOp::Lt,
">=" => BinaryOp::Gte,
"<=" => BinaryOp::Lte,
"+" => BinaryOp::Add,
"-" => BinaryOp::Subtract,
"/" => BinaryOp::Divide,
"%" => BinaryOp::Modulo,
"&" => BinaryOp::BitwiseAnd,
"|" => BinaryOp::BitwiseOr,
"^" => BinaryOp::BitwiseXor,
_ => break,
},
Some(Token::Star) => BinaryOp::Multiply,
Some(Token::Keyword(k)) if *k == Keyword::And => BinaryOp::And,
Some(Token::Keyword(k)) if *k == Keyword::Or => BinaryOp::Or,
_ => break,
};
let (l_bp, r_bp) = infix_binding_power(&op);
if l_bp < min_bp {
break;
}
let _ = parser.next();
let right = parse_pratt_expr(parser, r_bp)?;
left = Expr::Binary {
left: Box::new(left),
op,
right: Box::new(right),
};
}
Ok(left)
})();
parser.leave_recursion();
res
}
fn infix_binding_power(op: &BinaryOp) -> (u8, u8) {
match op {
BinaryOp::Or => (1, 2),
BinaryOp::And => (3, 4),
BinaryOp::Eq
| BinaryOp::NotEq
| BinaryOp::Gt
| BinaryOp::Lt
| BinaryOp::Gte
| BinaryOp::Lte
| BinaryOp::Like => (5, 6),
BinaryOp::BitwiseAnd | BinaryOp::BitwiseOr | BinaryOp::BitwiseXor => (7, 8),
BinaryOp::Add | BinaryOp::Subtract => (9, 10),
BinaryOp::Multiply | BinaryOp::Divide | BinaryOp::Modulo => (11, 12),
}
}
fn infix_binding_power_special(op: &str) -> (u8, u8) {
match op {
"LIKE" | "BETWEEN" | "IN" => (5, 6),
_ => (0, 0),
}
}
fn postfix_binding_power(_op: &Keyword) -> (u8, ()) {
(11, ())
}