pub enum Predecessor<T> {
    Parent(T),
    Previous(T),
}
Expand description

A statement in an AST may have:

  • A previous statement
  • A next statement
  • A child statement
  • A parent statement

Consider the example:

x = -10
loop
    x = x + 1
    if x
        break
x = 2

this can be represented as:

┌──────────┐
│x = -10   │
└──────────┘
│
┌──────────┐
│loop      │
└──────────┘
│           ╲
┌──────────┐ ┌─────────┐
│x = 2     │ │x = x + 1│
└──────────┘ └─────────┘
             │
             ┌─────────┐
             │if x     │
             └─────────┘
                        ╲
                         ┌─────────┐
                         │break    │
                         └─────────┘

this is a simplified tree structure.

Variants§

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Parent(T)

A parent element.

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Previous(T)

A previous element.

Implementations§

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impl<T> Predecessor<T>

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pub fn parent(self) -> Option<T>

Unwrap to a parent.

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pub fn previous(self) -> Option<T>

Unwraps to a previous.

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pub fn unwrap(self) -> T

Unwraps.

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pub fn as_ref(&self) -> Predecessor<&T>

Returns Predecessor<&T>.

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pub fn as_mut(&mut self) -> Predecessor<&mut T>

Returns Predecessor<&mut T>.

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pub fn map<P>(self, f: impl Fn(T) -> P) -> Predecessor<P>

Maps to Predecessor<P>.

Trait Implementations§

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impl<T: Clone> Clone for Predecessor<T>

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fn clone(&self) -> Predecessor<T>

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<T: Debug> Debug for Predecessor<T>

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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<T: PartialEq> PartialEq<Predecessor<T>> for Predecessor<T>

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fn eq(&self, other: &Predecessor<T>) -> 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.
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impl<T: Copy> Copy for Predecessor<T>

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impl<T: Eq> Eq for Predecessor<T>

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impl<T> StructuralEq for Predecessor<T>

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impl<T> StructuralPartialEq for Predecessor<T>

Auto Trait Implementations§

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impl<T> RefUnwindSafe for Predecessor<T>where T: RefUnwindSafe,

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impl<T> Send for Predecessor<T>where T: Send,

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impl<T> Sync for Predecessor<T>where T: Sync,

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impl<T> Unpin for Predecessor<T>where T: Unpin,

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impl<T> UnwindSafe for Predecessor<T>where T: UnwindSafe,

Blanket Implementations§

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impl<T> Any for Twhere 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 Twhere 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 Twhere 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 Twhere 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> ToOwned for Twhere 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, U> TryFrom<U> for Twhere 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 Twhere 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.