Struct BindingDecl 

pub struct BindingDecl {
    pub outputs: Vec<(String, ExprSpan)>,
    pub destructure: bool,
    pub body: Expr,
    pub leading_comment: Option<Comment>,
    pub trailing_line_comment: Option<Comment>,
    pub blank_line_before: bool,
    pub span: ExprSpan,
}

binding = binding_target ":=" expression ";". binding_target = identifier | "(" identifier "," [ identifier { "," identifier } ] ")".

The compiler deduces inputs from resolved cell references in body. The structural AST records only the explicit output names, without resolving cell declarations.

Parenthesizing the left-hand side requests tuple destructuring, matching Rust’s tuple-pattern syntax: (a, b) := ... and the single-element (a,) := ... (trailing comma mandatory, exactly as in a Rust 1-tuple pattern) both destructure body’s tuple result element-wise into outputs. A bare identifier binds body’s whole result directly to that one output instead. A parenthesized binding target always requires a comma; (a) := ... is invalid. See Self::destructure.

Examples

See Module for both direct and destructuring binding targets.

Fields

outputs: Vec<(String, ExprSpan)>

The binding’s output cell names (the left-hand side), in declaration order.

destructure: bool

Whether the left-hand side requests destructuring ((a, b) := ... or (a,) := ...) as opposed to a direct bind (a := ...). Always true when outputs.len() > 1; when outputs.len() == 1, distinguishes “destructure this single-element tuple” from “bind this whole value directly” — a distinction the parenthesized-or-not left-hand side is the only way to express, since both forms name exactly one output.

body: Expr

The parsed right-hand-side expression.

leading_comment: Option<Comment>

A leading comment immediately preceding this binding, if recovered by crate::trivia::attach_trivia.

trailing_line_comment: Option<Comment>

A ////* */ comment on the same source line as this binding’s own last token, if recovered by crate::trivia::attach_trivia. See https://github.com/stlab/cel-rs/issues/59.

blank_line_before: bool

Whether a blank line preceded this binding, if recovered by crate::trivia::attach_trivia.

span: ExprSpan

The span of the whole a := ...; / (a, b) := ...; declaration.

Trait Implementations

impl Clone for BindingDecl

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BindingDecl

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.