Struct rustlr::generic_absyn::LBox

pub struct LBox<T: ?Sized> {
    pub exp: Box<T>,
    pub line: usize,
    pub column: usize,
}

custom smart pointer that encapsulates line number and column. Source ID information is kept at the parser (RuntimeParser or ZCParser) level (since version 0.2.0). For warnings and error messages after the parsing stage. Implements Deref and DerefMut so the encapsulated expression can be accessed as in a standard Box.

Fields

exp: Box<T>

line: usize

column: usize

Implementations

impl<T> LBox<T>

pub fn new(e: T, ln: usize, col: usize) -> LBox<T>

pub fn transfer<U>(&self, e: U) -> LBox<U>

should be used to create a new LBoxed expression that inherits lexical information from existing LBox

impl<'t> LBox<dyn Any + 't>

pub fn downcast<U: 't>(self) -> Option<LBox<U>>

emulates Box::downcast function, when LBox<dyn Any> is used as the abstract syntax type. Note that unlike Box::downcast, an Option is returned here instead of a result.

pub fn upcast<T: 't>(lb: LBox<T>) -> Self

do not try to create a LBox<dyn Any> structure with something like

 let lb:LBox<dyn Any> = LBox::new(String::from("abc"),0,0);

This does not work as LBox is simply borrowing the underlying mechanics of Box instead of re-creating them. Do instead:

 let lb:LBox<dyn Any> = LBox::upcast(LBox::new(String::from("abc"),0,0));

upcast always returns a LBox<dyn Any>.

Trait Implementations

impl<T: Clone> Clone for LBox<T>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for LBox<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for LBox<T>

fn default() -> Self

Returns the “default value” for a type.

impl Default for LBox<dyn Any>

this is provided so LBox<dyn Any> can be used for the abstract syntax type. the default is a Lbox containing a static string.

fn default() -> Self

Returns the “default value” for a type.

impl<T> Deref for LBox<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> DerefMut for LBox<T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.