use std::{convert::From, default::Default};
use crate::{
binding::global::RubySpecialConsts,
types::{InternalValue, Value, ValueType},
AnyObject, Object, VerifiedObject,
};
#[derive(Debug, Copy, Clone)]
#[repr(C)]
pub struct NilClass {
value: Value,
}
impl NilClass {
pub fn new() -> Self {
Self::from(Value::from(RubySpecialConsts::Nil as InternalValue))
}
}
impl Default for NilClass {
fn default() -> Self {
NilClass::new()
}
}
impl From<Value> for NilClass {
fn from(value: Value) -> Self {
NilClass { value }
}
}
impl Into<Value> for NilClass {
fn into(self) -> Value {
self.value
}
}
impl Into<AnyObject> for NilClass {
fn into(self) -> AnyObject {
AnyObject::from(self.value)
}
}
impl Object for NilClass {
#[inline]
fn value(&self) -> Value {
self.value
}
}
impl VerifiedObject for NilClass {
fn is_correct_type<T: Object>(object: &T) -> bool {
object.value().ty() == ValueType::Nil
}
fn error_message() -> &'static str {
"Error converting to NilClass"
}
}
impl PartialEq for NilClass {
fn eq(&self, other: &Self) -> bool {
self.equals(other)
}
}
#[cfg(test)]
mod tests {
use crate::{AnyObject, Boolean, NilClass, Object, VerifiedObject, VM};
#[test]
fn test_nil_class() {
crate::on_ruby_thread(|| {
let nil = NilClass::new();
assert!(nil.is_nil());
assert_eq!(nil, NilClass::default());
let any: AnyObject = nil.into();
assert!(NilClass::is_correct_type(&any));
assert!(!NilClass::is_correct_type(&Boolean::new(false)));
assert!(Boolean::new(false).try_convert_to::<NilClass>().is_err());
assert!(VM::eval("[].first")
.unwrap()
.try_convert_to::<NilClass>()
.is_ok());
});
}
}