Enum lexpr::parse::NilSymbol

pub enum NilSymbol {
    EmptyList,
    Default,
    Special,
}

Defines the handling of the symbol nil.

Variants

EmptyList

Parse nil like as the empty list. This the behavior of Emacs Lisp and Common Lisp.

In the parsed Value, the empty list, written as () and the empty list, written as nil are both represented by the Value::List variant with zero elements.

Default

Parse nil as a regular symbol. This is the behavior found in Scheme.

The parsed Value will be equal to Value::symbol("nil").

Special

Parse nil as a special atom. This allows treating the nil symbol specially when processing the parsed data.

The parsed Value will be equal to Value::nil().

Trait Implementations

impl PartialEq<NilSymbol> for NilSymbol

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

This method tests for self and other values to be equal, and is used by ==.

#[must_use]

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

This method tests for !=.

impl Clone for NilSymbol

fn clone(&self) -> NilSymbol

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for NilSymbol

impl Debug for NilSymbol

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

Formats the value using the given formatter.