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VariableContext

Struct VariableContext 

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pub struct VariableContext {
    pub next_index: VariableId,
}
Expand description

Context for creating variables in a query. The context keeps track of the next index to assign to a variable. This allows for the creation of new anonymous variables in higher-level query languages.

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§next_index: VariableId

The index that will be assigned to the next variable.

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impl VariableContext

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pub fn new() -> Self

Create a new variable context. The context starts with an index of 0.

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pub fn next_variable<T: InlineEncoding>(&mut self) -> Variable<T>

Create a new variable. The variable is assigned the next available index.

Panics if the number of variables exceeds 128.

This method is usually not called directly, but rather through typed query language macros like find!.

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impl Debug for VariableContext

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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 Default for VariableContext

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fn default() -> Self

Returns the “default value” for a type. Read more

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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> ArchiveOwner for T
where T: Send + Sync + 'static + ?Sized,

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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<ST, DT> CastableFrom<ST, Initialized, Initialized> for DT
where ST: ?Sized, DT: ?Sized,

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impl<ST, DT> CastableFrom<ST, Uninit, Uninit> for DT
where ST: ?Sized, DT: ?Sized,

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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<S, T> IntoBlob<S> for T
where S: BlobEncoding, T: IntoEncoded<S, Output = Blob<S>>,

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fn to_blob(self) -> Blob<S>
where Self: Sized,

Convert directly to Blob<S>.
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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<S, T> IntoEncoded<S> for T
where S: Encodes<T>,

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type Output = <S as Encodes<T>>::Output

The concrete form this source produces.
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fn into_encoded(self) -> <T as IntoEncoded<S>>::Output

Run the conversion.
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impl<S, T> IntoInline<S> for T
where S: InlineEncoding, T: IntoEncoded<S, Output = Inline<S>>,

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fn to_inline(self) -> Inline<S>
where Self: Sized,

Convert directly to Inline<S>.
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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Read<Exclusive, BecauseExclusive> for T
where T: ?Sized,

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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, 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