[−][src]Struct emacs::Value
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>
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pub fn is_not_nil(&self) -> bool
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pub fn eq(&self, other: Value<'e>) -> bool
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pub fn into_rust<T: FromLisp<'e>>(self) -> Result<T>
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Converts this value into a Rust value of the given type.
pub fn into_ref<T: 'static>(self) -> Result<Ref<'e, T>>
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pub fn into_ref_mut<T: 'static>(self) -> Result<RefMut<'e, T>>
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pub unsafe fn get_mut<T: Transfer>(&mut self) -> Result<&mut T>
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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.
impl<'e> Value<'e>
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pub fn copy_string_contents(self, buffer: &mut [u8]) -> Result<&[u8]>
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Copies the content of this Lisp string value to the given buffer as a null-terminated UTF-8 string. Returns the copied bytes, excluding the null terminator.
Signals an args-out-of-range
error if the buffer is too small.
impl<'e> Value<'e>
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pub fn call<A>(self, args: A) -> Result<Value<'e>> where
A: IntoLispArgs<'e>,
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A: IntoLispArgs<'e>,
Calls this value with the given arguments. An error is signaled if it is actually not a Lisp's callable.
args
should be an array/slice of Value
, or a tuple of different types, each implementing
IntoLisp
.
Examples
#[defun] fn mapc_enumerate_vec(function: Value, vector: Vector) -> Result<()> { for nth in 0..vector.size()? { let elem: Value = vector.get(nth)?; function.call((nth, elem))?; } Ok(()) }
Trait Implementations
impl<'a, 'e: 'a> FromLisp<'e> for Value<'a>
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impl<'e> IntoLisp<'e> for Value<'e>
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impl<'e> Clone for Value<'e>
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impl<'e> Copy for Value<'e>
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impl<'e> Debug for Value<'e>
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Auto Trait Implementations
impl<'e> !Send for Value<'e>
impl<'e> !Sync for Value<'e>
impl<'e> Unpin for Value<'e>
impl<'e> !UnwindSafe for Value<'e>
impl<'e> !RefUnwindSafe for Value<'e>
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = !
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,