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use crate::{
dialect::Dialect,
expression::{Operator, PostfixOperator, UnaryOperator},
instr::RpnInstr,
};
/// <https://matklad.github.io/2020/04/13/simple-but-powerful-pratt-parsing.html>
/// <https://www.postgresql.org/docs/18/sql-syntax-lexical.html#SQL-PRECEDENCE>
/// <https://dev.mysql.com/doc/refman/9.6/en/operator-precedence.html>
/// <https://sqlite.org/lang_expr.html#operators>
pub(crate) fn binding_power(op: &RpnInstr, dialect: Dialect) -> (u8, u8) {
match dialect {
Dialect::Postgres => match op {
RpnInstr::Binary { op, .. } => match op {
Operator::And => (3, 4),
Operator::Or => (1, 2),
Operator::Gt
| Operator::Lt
| Operator::Gte
| Operator::Lte
| Operator::Eq
| Operator::Neq => (9, 10),
Operator::Add | Operator::Sub => (13, 14),
Operator::Mul | Operator::Div | Operator::Rem => (15, 16),
Operator::Like { .. } => (11, 12),
Operator::BitAnd => (13, 14),
Operator::BitOr => (13, 14),
Operator::Shl | Operator::Shr => (13, 14),
},
RpnInstr::Between { .. } => (11, 12),
RpnInstr::Unary {
op: UnaryOperator::Not,
..
} => (6, 5),
RpnInstr::Postfix {
op: PostfixOperator::Null { .. } | PostfixOperator::False | PostfixOperator::True,
..
} => (7, 8),
_ => (0, 0),
},
Dialect::MariaDb => match op {
RpnInstr::Unary {
op: UnaryOperator::Not,
..
} => (6, 5),
RpnInstr::Binary { op, .. } => match op {
Operator::And => (3, 4),
Operator::Or => (1, 2),
Operator::Gt
| Operator::Lt
| Operator::Gte
| Operator::Lte
| Operator::Eq
| Operator::Neq => (9, 10),
Operator::Add | Operator::Sub => (15, 16),
Operator::Mul | Operator::Div | Operator::Rem => (16, 17),
Operator::Like { .. } => (9, 10),
Operator::BitAnd => (11, 12),
Operator::BitOr => (11, 12),
Operator::Shl | Operator::Shr => (13, 14),
},
RpnInstr::Between { .. } => (7, 8),
RpnInstr::Postfix {
op: PostfixOperator::Null { .. } | PostfixOperator::False | PostfixOperator::True,
..
} => (9, 10),
_ => (0, 0),
},
Dialect::Sqlite => match op {
RpnInstr::Binary { op, .. } => match op {
Operator::And => (3, 4),
Operator::Or => (1, 2),
Operator::Gt | Operator::Lt | Operator::Gte | Operator::Lte => (9, 10),
Operator::Eq | Operator::Neq => (7, 8),
Operator::Add | Operator::Sub => (13, 14),
Operator::Mul | Operator::Div | Operator::Rem => (15, 16),
Operator::Like { .. } => (7, 8),
Operator::BitAnd => (11, 12),
Operator::BitOr => (11, 12),
Operator::Shl | Operator::Shr => (13, 14),
},
RpnInstr::Unary {
op: UnaryOperator::Not,
..
} => (6, 5),
RpnInstr::Postfix {
op: PostfixOperator::Null { .. } | PostfixOperator::False | PostfixOperator::True,
..
} => (7, 8),
RpnInstr::Between { .. } => (7, 8),
_ => (0, 0),
},
}
}
#[cfg(test)]
mod tests {
use super::binding_power;
use crate::{
dialect::Dialect,
expression::{Operator, PostfixOperator, UnaryOperator},
instr::RpnInstr,
};
#[test]
fn binding_power_matches_expected_binary_operators_for_all_dialects() {
let cases = [
(
Dialect::Postgres,
RpnInstr::Binary {
op: Operator::Eq,
lhs: 1,
rhs: 1,
},
(9, 10),
),
(
Dialect::Postgres,
RpnInstr::Binary {
op: Operator::Mul,
lhs: 1,
rhs: 1,
},
(15, 16),
),
(
Dialect::MariaDb,
RpnInstr::Binary {
op: Operator::Like {
sensitive: false,
negated: false,
},
lhs: 1,
rhs: 1,
},
(9, 10),
),
(
Dialect::MariaDb,
RpnInstr::Binary {
op: Operator::BitAnd,
lhs: 1,
rhs: 1,
},
(11, 12),
),
(
Dialect::Sqlite,
RpnInstr::Binary {
op: Operator::Eq,
lhs: 1,
rhs: 1,
},
(7, 8),
),
(
Dialect::Sqlite,
RpnInstr::Binary {
op: Operator::Shl,
lhs: 1,
rhs: 1,
},
(13, 14),
),
];
for (dialect, instr, expected) in cases {
assert_eq!(binding_power(&instr, dialect), expected);
}
}
#[test]
fn postgres_binding_power_matches_qrafting_shape() {
assert_eq!(
binding_power(
&RpnInstr::Binary {
op: Operator::And,
lhs: 1,
rhs: 1,
},
Dialect::Postgres,
),
(3, 4)
);
assert_eq!(
binding_power(
&RpnInstr::Binary {
op: Operator::Like {
sensitive: false,
negated: false,
},
lhs: 1,
rhs: 1,
},
Dialect::Postgres,
),
(11, 12)
);
assert_eq!(
binding_power(
&RpnInstr::Unary {
op: UnaryOperator::Not,
rhs: 1,
},
Dialect::Postgres,
),
(6, 5)
);
assert_eq!(
binding_power(
&RpnInstr::Postfix {
op: PostfixOperator::True,
lhs: 1,
},
Dialect::Postgres,
),
(7, 8)
);
}
#[test]
fn binding_power_matches_unary_and_postfix_operators_for_all_dialects() {
for (dialect, postfix_expected) in [
(Dialect::Postgres, (7, 8)),
(Dialect::MariaDb, (9, 10)),
(Dialect::Sqlite, (7, 8)),
] {
assert_eq!(
binding_power(
&RpnInstr::Unary {
op: UnaryOperator::Not,
rhs: 1,
},
dialect,
),
(6, 5)
);
assert_eq!(
binding_power(
&RpnInstr::Between {
lhs: 1,
low: 1,
high: 1,
negated: false,
},
dialect,
),
match dialect {
Dialect::Postgres => (11, 12),
Dialect::MariaDb | Dialect::Sqlite => (7, 8),
}
);
assert_eq!(
binding_power(
&RpnInstr::Postfix {
op: PostfixOperator::Null { negated: false },
lhs: 1,
},
dialect,
),
postfix_expected
);
}
}
}