Struct Closure 

pub struct Closure {
    pub is_async: bool,
    pub arity: usize,
    pub body: ClosureBody,
    pub module: Rc<str>,
    pub captures: Vec<(Rc<str>, Value)>,
}

A closure captures its environment by value at creation time.

Fields

is_async: bool

arity: usize

How many parameters this closure declares.

The whole of its signature that anything outside the backend that built it asks for, and the reason it is a number rather than the parameter list it used to be. Every reader wanted a count: crate::builtins::Callable::arity answers out of this, Result.mapError reads it to decide whether to hand its callback the error it is replacing, and builtins::expect_callback refuses a callback of the wrong shape in one place rather than at every call site that needs the check. None of them wanted a name, a default, a type or a span, and issue #121 is where each was asked and answered.

It counts parameters, not arguments a call must supply: a defaulted or a variadic parameter is one of these like any other, which is what params.len() answered when this was a Vec<Param>.

body: ClosureBody

module: Rc<str>

The module a closure body resolves names in.

captures: Vec<(Rc<str>, Value)>

Trait Implementations

impl Debug for Closure

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

Formats the value using the given formatter.