Enum Preceding

pub enum Preceding<T> {
    Parent(T),
    Previous(T),
}

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

Parent(T)

A parent element.

Previous(T)

A previous element.

Implementations

impl<T> Preceding<T>

pub fn is_parent(&self) -> bool

Returns if self is a parent.

pub fn is_previous(&self) -> bool

Returns if self is a previous.

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

Unwrap to a parent.

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

Unwraps to a previous.

pub fn unwrap(self) -> T

Unwraps.

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

Returns Preceding<&T>.

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

Returns Preceding<&mut T>.

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

Maps to Preceding<P>.

Trait Implementations

impl<T: Clone> Clone for Preceding<T>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Preceding<T>

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

Formats the value using the given formatter.

impl<T: PartialEq> PartialEq for Preceding<T>

fn eq(&self, other: &Preceding<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

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

impl<T: Copy> Copy for Preceding<T>

impl<T: Eq> Eq for Preceding<T>

impl<T> StructuralPartialEq for Preceding<T>