toasty_core/stmt/
expr_cast.rs

1use super::{Expr, Type};
2
3/// A type cast expression.
4///
5/// Converts an expression's value to a different type.
6///
7/// # Examples
8///
9/// ```text
10/// cast(x, i64)     // cast `x` to `i64`
11/// cast(y, string)  // cast `y` to `string`
12/// ```
13#[derive(Debug, Clone, PartialEq)]
14pub struct ExprCast {
15    /// The expression to cast.
16    pub expr: Box<Expr>,
17
18    /// The source type, when the value alone cannot direct the conversion.
19    ///
20    /// Most casts are directed by the target type and the value's own shape,
21    /// and leave this `None`. The exception is a `#[document]` column's
22    /// lowering cast (`Type::Model` → `Type::Object`): the structural target
23    /// does not name the embedded model and a positional `Value::Record` is
24    /// not self-describing, so the cast carries the model-level source type
25    /// to resolve the embed's field names.
26    pub from: Option<Type>,
27
28    /// The target type.
29    pub ty: Type,
30}
31
32impl Expr {
33    /// Creates a type cast expression that converts `expr` to the target type.
34    pub fn cast(expr: impl Into<Self>, ty: impl Into<Type>) -> Self {
35        ExprCast {
36            expr: Box::new(expr.into()),
37            from: None,
38            ty: ty.into(),
39        }
40        .into()
41    }
42
43    /// Creates a type cast expression whose conversion is directed by the
44    /// source type as well as the target type. See [`ExprCast::from`].
45    pub fn cast_from(expr: impl Into<Self>, from: impl Into<Type>, ty: impl Into<Type>) -> Self {
46        ExprCast {
47            expr: Box::new(expr.into()),
48            from: Some(from.into()),
49            ty: ty.into(),
50        }
51        .into()
52    }
53
54    /// Returns `true` if this expression is a type cast.
55    pub fn is_cast(&self) -> bool {
56        matches!(self, Self::Cast(_))
57    }
58}
59
60impl From<ExprCast> for Expr {
61    fn from(value: ExprCast) -> Self {
62        Self::Cast(value)
63    }
64}
toasty_core/stmt/expr_cast.rs

toasty_core/stmt/
expr_cast.rs
