forked from Orchid/orchid
89 lines
3.1 KiB
Rust
89 lines
3.1 KiB
Rust
use std::any::Any;
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use std::fmt::{Display, Debug};
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use std::hash::Hash;
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use std::rc::Rc;
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use dyn_clone::DynClone;
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use crate::representations::interpreted::{Clause, RuntimeError, InternalError};
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pub trait ExternError: Display {
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fn into_extern(self) -> Rc<dyn ExternError> where Self: 'static + Sized {
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Rc::new(self)
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}
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}
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/// Represents an externally defined function from the perspective of the executor
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/// Since Orchid lacks basic numerical operations, these are also external functions.
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pub trait ExternFn: DynClone {
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fn name(&self) -> &str;
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fn apply(&self, arg: Clause) -> Result<Clause, Rc<dyn ExternError>>;
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fn hash(&self, state: &mut dyn std::hash::Hasher) { state.write_str(self.name()) }
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}
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impl Eq for dyn ExternFn {}
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impl PartialEq for dyn ExternFn {
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fn eq(&self, other: &Self) -> bool { self.name() == other.name() }
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}
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impl Hash for dyn ExternFn {
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fn hash<H: std::hash::Hasher>(&self, state: &mut H) { self.name().hash(state) }
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}
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impl Debug for dyn ExternFn {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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write!(f, "##EXTERN[{}]##", self.name())
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}
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}
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pub trait Atomic: Any + Debug + DynClone where Self: 'static {
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fn as_any(&self) -> &dyn Any;
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fn definitely_eq(&self, _other: &dyn Any) -> bool;
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fn hash(&self, hasher: &mut dyn std::hash::Hasher);
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fn run_once(&self) -> Result<Clause, InternalError>;
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fn run_n_times(&self, n: usize) -> Result<(Clause, usize), RuntimeError>;
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fn run_to_completion(&self) -> Result<Clause, RuntimeError>;
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fn typestr(&self) -> &str { "clause" }
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}
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/// Represents a black box unit of code with its own normalization steps. Typically [ExternFn]
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/// will produce an [Atom] when applied to a [Clause], this [Atom] will then forward `run_*` calls
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/// to the argument until it yields [InternalError::NonReducible] at which point the [Atom] will
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/// validate and process the argument, returning a different [Atom] intended for processing by
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/// external code, a new [ExternFn] to capture an additional argument, or an Orchid expression
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/// to pass control back to the interpreter.
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pub struct Atom(pub Box<dyn Atomic>);
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impl Atom {
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pub fn new<T: 'static + Atomic>(data: T) -> Self {
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Self(Box::new(data) as Box<dyn Atomic>)
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}
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pub fn data(&self) -> &dyn Atomic { self.0.as_ref() as &dyn Atomic }
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pub fn try_cast<T: Atomic>(&self) -> Result<&T, ()> {
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self.data().as_any().downcast_ref().ok_or(())
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}
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pub fn is<T: 'static>(&self) -> bool { self.data().as_any().is::<T>() }
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pub fn cast<T: 'static>(&self) -> &T {
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self.data().as_any().downcast_ref().expect("Type mismatch on Atom::cast")
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}
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}
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impl Clone for Atom {
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fn clone(&self) -> Self {
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Self(dyn_clone::clone_box(self.data()))
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}
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}
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impl Hash for Atom {
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fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
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self.0.hash(state)
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}
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}
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impl Debug for Atom {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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write!(f, "##ATOM[{:?}]:{:?}##", self.data(), self.data().typestr())
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}
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}
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impl Eq for Atom {}
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impl PartialEq for Atom {
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fn eq(&self, other: &Self) -> bool {
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self.data().definitely_eq(other.data().as_any())
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}
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} |