toasty_core/stmt/
expr_match.rs

1use super::{Expr, Value};
2
3/// A match expression that dispatches on a subject expression.
4///
5/// Each arm matches the subject against a constant value pattern and evaluates
6/// the corresponding expression. `Expr::Match` is never serialized to SQL — it
7/// is either evaluated in the engine (for writes) or eliminated by the
8/// simplifier before the plan stage (for reads/queries).
9#[derive(Debug, Clone, PartialEq)]
10pub struct ExprMatch {
11    /// The expression to dispatch on.
12    pub subject: Box<Expr>,
13
14    /// The match arms, in order.
15    pub arms: Vec<MatchArm>,
16
17    /// Fallback expression evaluated when no arm matches.
18    pub else_expr: Box<Expr>,
19}
20
21/// A single arm in a match expression.
22#[derive(Debug, Clone, PartialEq)]
23pub struct MatchArm {
24    /// The constant value pattern this arm matches against.
25    pub pattern: Value,
26
27    /// The expression to evaluate when the pattern matches.
28    pub expr: Expr,
29}
30
31impl Expr {
32    /// Creates a `Match` expression that dispatches on `subject`.
33    pub fn match_expr(
34        subject: impl Into<Self>,
35        arms: Vec<MatchArm>,
36        else_expr: impl Into<Self>,
37    ) -> Self {
38        ExprMatch {
39            subject: Box::new(subject.into()),
40            arms,
41            else_expr: Box::new(else_expr.into()),
42        }
43        .into()
44    }
45}
46
47impl From<ExprMatch> for Expr {
48    fn from(value: ExprMatch) -> Self {
49        Self::Match(value)
50    }
51}
toasty_core/stmt/expr_match.rs

toasty_core/stmt/
expr_match.rs
