Struct emacs::Value

pub struct Value<'e> {
    pub env: &'e Env,
    // some fields omitted
}

A type that represents Lisp values. Values of this type can be copied around, but are lifetime-bound to the Env they come from.

They are also "proxy values" that are only useful when converted to Rust values, or used as arguments when calling back into the Lisp runtime.

Fields

env: &'e Env

Methods

impl<'e> Value<'e>

pub fn into_rust<T: FromLisp<'e>>(self) -> Result<T>

Converts this value into a Rust value of the given type.

pub unsafe fn get_mut<T: Transfer>(&mut self) -> Result<&mut T>

Returns a mutable reference to the underlying Rust data wrapped by this value.

Safety

There are several ways this can go wrong:

• Lisp code can pass the same object through 2 different values in an argument list.
• Rust code earlier in the call chain may have copied this value.
• Rust code later in the call chain may receive a copy of this value.

In general, it is better to wrap Rust data in RefCell, Mutex, or RwLock guards, before moving them to Lisp, and then only access them through these guards (which can be obtained back through into_rust). This method is for squeezing out the last bit of performance in very rare situations.

Trait Implementations

impl<'a, 'e: 'a> FromLisp<'e> for Value<'a>

fn from_lisp(value: Value<'e>) -> Result<Value<'a>>

impl<'e> IntoLisp<'e> for Value<'e>

fn into_lisp(self, _env: &'e Env) -> Result<Value>

impl<'e> Copy for Value<'e>

impl<'e> Clone for Value<'e>

fn clone(&self) -> Value<'e>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'e> Debug for Value<'e>

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

Formats the value using the given formatter.