pub struct Builtin(Box<BuiltinRepr>);
Expand description

Represents a single built-in function which directly executes Rust code that operates on a Nix value.

Builtins are the only functions in Nix that have varying arities (for example, hasAttr has an arity of 2, but isAttrs an arity of 1). To facilitate this generically, builtins expect to be called with a vector of Nix values corresponding to their arguments in order.

Partially applied builtins act similar to closures in that they “capture” the partially applied arguments, and are treated specially when printing their representation etc.

Tuple Fields§

§0: Box<BuiltinRepr>

Implementations§

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impl Builtin

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pub fn new<F: BuiltinGen + 'static>( name: &'static str, documentation: Option<&'static str>, arg_count: usize, func: F ) -> Self

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pub fn name(&self) -> &'static str

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pub fn documentation(&self) -> Option<&'static str>

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pub fn apply_arg(&mut self, arg: Value)

Apply an additional argument to the builtin. After this, Builtin::call must be called, otherwise it may leave the builtin in an incorrect state.

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pub fn call(self) -> BuiltinResult

Attempt to call a builtin, which will produce a generator if it is fully applied or return the builtin if it is partially applied.

Trait Implementations§

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impl Clone for Builtin

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fn clone(&self) -> Builtin

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Builtin

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

Formats the value using the given formatter. Read more
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impl Display for Builtin

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

Formats the value using the given formatter. Read more
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impl From<BuiltinRepr> for Builtin

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fn from(value: BuiltinRepr) -> Self

Converts to this type from the input type.
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impl PartialEq for Builtin

Builtins are uniquely identified by their name

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fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

Auto Trait Implementations§

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impl !RefUnwindSafe for Builtin

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impl !Send for Builtin

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impl !Sync for Builtin

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impl Unpin for Builtin

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impl !UnwindSafe for Builtin

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToSmolStr for T
where T: Display + ?Sized,

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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V