stak-native 0.10.33

Optimized primitives of native functions for Stak Scheme
Documentation 
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use stak_vm::{Error, Memory, PrimitiveSet, Type};
use winter_maybe_async::maybe_async;

/// A type check primitive.
pub enum TypeCheckPrimitive {
    /// A null type check.
    Null,
    /// A pair type check.
    Pair,
}

impl TypeCheckPrimitive {
    const NULL: usize = Self::Null as _;
    const PAIR: usize = Self::Pair as _;
}

/// A type check primitive set.
#[derive(Debug, Default)]
pub struct TypeCheckPrimitiveSet {}

impl TypeCheckPrimitiveSet {
    /// Creates a primitive set.
    pub fn new() -> Self {
        Self::default()
    }
}

impl PrimitiveSet for TypeCheckPrimitiveSet {
    type Error = Error;

    #[maybe_async]
    fn operate(&mut self, memory: &mut Memory<'_>, primitive: usize) -> Result<(), Self::Error> {
        match primitive {
            TypeCheckPrimitive::NULL => memory.operate_top(|memory, value| {
                Ok(memory.boolean(value == memory.null()?.into())?.into())
            })?,
            TypeCheckPrimitive::PAIR => memory.operate_top(|memory, value| {
                Ok(memory
                    .boolean(
                        value
                            .to_cons()
                            .map(|cons| Ok::<_, Error>(memory.cdr(cons)?.tag() == Type::Pair as _))
                            .transpose()?
                            .unwrap_or_default(),
                    )?
                    .into())
            })?,
            _ => return Err(Error::IllegalPrimitive),
        }

        Ok(())
    }
}