309 lines
15 KiB
Rust
309 lines
15 KiB
Rust
use std::fmt;
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use std::boxed::Box;
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use std::rc::Rc;
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use std::cell::RefCell;
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use std::convert::From;
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use crate::eval::{FormT,Cont,Cursor,PrimCombI};
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#[derive(Debug, Eq, PartialEq)]
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pub enum Form {
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Nil,
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Int(i32),
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Bool(bool),
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Symbol(String),
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Cell(RefCell<Rc<Form>>),
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Pair(Rc<Form>,Rc<Form>),
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PrimComb { eval_limit: i32, ins: PrimCombI },
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DeriComb { se: Rc<Form>, de: Option<String>, params: String, body: Rc<Form> },
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ContComb(Cont<Form>),
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}
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// todo, strings not symbols?
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impl From<String> for Form { fn from(item: String) -> Self { Form::Symbol(item) } }
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impl From<&str> for Form { fn from(item: &str) -> Self { Form::Symbol(item.to_owned()) } }
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impl From<i32> for Form { fn from(item: i32) -> Self { Form::Int(item) } }
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impl From<bool> for Form { fn from(item: bool) -> Self { Form::Bool(item) } }
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impl<A: Into<Form>, B: Into<Form>> From<(A, B)> for Form {
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fn from(item: (A, B)) -> Self {
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Form::Pair(Rc::new(item.0.into()), Rc::new(item.1.into()))
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}
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}
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impl fmt::Display for Form {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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match self {
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Form::Nil => write!(f, "nil"),
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Form::Int(i) => write!(f, "{i}"),
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Form::Bool(b) => write!(f, "{b}"),
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Form::Symbol(s) => write!(f, "{s}"),
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Form::Cell(c) => write!(f, "@{}", c.borrow()),
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Form::Pair(car, cdr) => {
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write!(f, "({}", car)?;
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let mut traverse: Rc<Form> = Rc::clone(cdr);
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loop {
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match &*traverse {
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Form::Pair(ref carp, ref cdrp) => {
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write!(f, " {}", carp)?;
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traverse = Rc::clone(cdrp);
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},
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Form::Nil => {
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write!(f, ")")?;
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return Ok(());
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},
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x => {
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write!(f, ". {x})")?;
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return Ok(());
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},
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}
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}
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},
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Form::PrimComb { eval_limit, ins } => write!(f, "<{eval_limit}> - {ins:?}"),
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Form::DeriComb { se: _, de, params, body } => {
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write!(f, "<{} {} {}>", de.as_ref().unwrap_or(&"".to_string()), params, body)
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},
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Form::ContComb(_) => write!(f, "<cont>"),
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}
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}
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}
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impl Form {
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fn truthy(&self) -> bool {
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match self {
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Form::Bool(b) => *b,
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Form::Nil => false,
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_ => true,
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}
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}
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fn int(&self) -> Option<i32> {
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match self {
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Form::Int(i) => Some(*i),
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_ => None,
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}
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}
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pub fn append(&self, x: Rc<Form>) -> Option<Rc<Form>> {
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match self {
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Form::Pair(car, cdr) => cdr.append(x).map(|x| Rc::new(Form::Pair(Rc::clone(car), x))),
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Form::Nil => Some(Rc::new(Form::Pair(x, Rc::new(Form::Nil)))),
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_ => None,
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}
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}
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}
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impl FormT for Form {
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fn sym(&self) -> Option<&str> {
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match self {
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Form::Symbol(s) => Some(s),
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_ => None,
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}
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}
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fn pair(&self) -> Option<(Rc<Form>,Rc<Form>)> {
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match self {
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Form::Pair(car, cdr) => Some((Rc::clone(car),Rc::clone(cdr))),
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_ => None,
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}
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}
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fn car(&self) -> Option<Rc<Form>> {
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match self {
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Form::Pair(car, _cdr) => Some(Rc::clone(car)),
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_ => None,
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}
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}
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fn cdr(&self) -> Option<Rc<Form>> {
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match self {
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Form::Pair(_car, cdr) => Some(Rc::clone(cdr)),
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_ => None,
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}
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}
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fn is_nil(&self) -> bool {
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match self {
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Form::Nil => true,
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_ => false,
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}
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}
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fn call(&self, p: Rc<Self>, e: Rc<Self>, nc: Box<Cont<Self>>, metac: Cont<Self>) -> Cursor<Self> {
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match self {
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Form::PrimComb{eval_limit, ins} => {
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Cursor { f: Rc::new(Form::Nil), c: Cont::PramEval { eval_limit: *eval_limit, to_eval: p, collected: None, e, ins: *ins, nc: nc }, metac }
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}
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Form::DeriComb {se, de, params, body} => {
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let mut new_e = Rc::clone(se);
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if let Some(de) = de {
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new_e = assoc(&de, Rc::clone(&e), new_e);
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}
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new_e = assoc(¶ms, p, new_e);
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Cursor { f: Rc::clone(body), c: Cont::Eval { e: new_e, nc: nc }, metac }
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}
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Form::ContComb(c) => {
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Cursor { f: p.car().unwrap(), c: Cont::Eval { e, nc: Box::new(c.clone()) }, metac: Cont::CatchRet { nc: nc, restore_meta: Box::new(metac) } }
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}
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_ => {
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panic!("Tried to call not a Prim/DeriComb/ContComb {:?}, nc was {:?}", self, nc);
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}
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}
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}
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fn impl_prim(ins: PrimCombI, e: Rc<Self>, ps: Vec<Rc<Self>>, c: Cont<Self>, metac: Cont<Self>) -> Cursor<Self> {
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match ins {
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PrimCombI::Eval => Cursor { f: Rc::clone(&ps[0]), c: Cont::Eval { e: Rc::clone(&ps[1]), nc: Box::new(c) }, metac },
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PrimCombI::Vau => {
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let de = ps[0].sym().map(|s| s.to_owned());
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let params = ps[1].sym().unwrap().to_owned();
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let body = Rc::clone(&ps[2]);
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Cursor { f: Rc::new(Form::DeriComb { se: e, de, params, body }), c, metac }
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},
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PrimCombI::If => if ps[0].truthy() {
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Cursor { f: Rc::clone(&ps[1]), c: Cont::Eval { e: e, nc: Box::new(c) }, metac }
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} else {
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Cursor { f: Rc::clone(&ps[2]), c: Cont::Eval { e: e, nc: Box::new(c) }, metac }
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},
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PrimCombI::Reset => Cursor { f: Rc::clone(&ps[0]),
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c: Cont::Eval { e: e, nc: Box::new(Cont::MetaRet) },
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metac: Cont::CatchRet { nc: Box::new(c), restore_meta: Box::new(metac) } },
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PrimCombI::Shift => Cursor { f: Rc::clone(&ps[0]),
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c: Cont::Call { p: Rc::new(Form::Pair(Rc::new(Form::ContComb(c)),
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Rc::new(Form::Nil))),
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e: e,
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nc: Box::new(Cont::MetaRet) },
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// I think this is unnecessary and can just be "metac },"
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// because reset puts this metac in
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metac: Cont::CatchRet { nc: Box::new(metac.clone()), restore_meta: Box::new(metac) } },
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PrimCombI::Assert => {
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let thing = Rc::clone(&ps[0]);
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if !thing.truthy() {
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println!("Assert failed: {:?}", thing);
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}
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assert!(thing.truthy());
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Cursor { f: Rc::clone(&ps[1]), c: Cont::Eval { e: e, nc: Box::new(c) }, metac }
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},
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PrimCombI::Cell => Cursor { f: Rc::new(Form::Cell(RefCell::new(Rc::clone(&ps[0])))), c, metac },
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PrimCombI::Set => match &*ps[0] {
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Form::Cell(cell) => Cursor { f: cell.replace(Rc::clone(&ps[1])), c, metac },
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_ => panic!("set on not cell"),
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},
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PrimCombI::Get => match &*ps[0] {
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Form::Cell(cell) => Cursor { f: Rc::clone(&cell.borrow()), c, metac },
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_ => panic!("get on not cell"),
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},
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PrimCombI::Cons => Cursor { f: Rc::new(Form::Pair(Rc::clone(&ps[0]), Rc::clone(&ps[1]))), c, metac },
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PrimCombI::Car => Cursor { f: ps[0].car().unwrap(), c, metac },
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PrimCombI::Cdr => Cursor { f: ps[0].cdr().unwrap(), c, metac },
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PrimCombI::Quote => Cursor { f: Rc::clone(&ps[0]), c, metac },
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PrimCombI::Eq => Cursor { f: Rc::new(Form::Bool(ps[0] == ps[1])), c, metac },
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PrimCombI::Lt => Cursor { f: Rc::new(Form::Bool(ps[0].int().unwrap() < ps[1].int().unwrap())), c, metac },
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PrimCombI::LEq => Cursor { f: Rc::new(Form::Bool(ps[0].int().unwrap() <= ps[1].int().unwrap())), c, metac },
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PrimCombI::Gt => Cursor { f: Rc::new(Form::Bool(ps[0].int().unwrap() > ps[1].int().unwrap())), c, metac },
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PrimCombI::GEq => Cursor { f: Rc::new(Form::Bool(ps[0].int().unwrap() >= ps[1].int().unwrap())), c, metac },
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PrimCombI::Plus => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() + ps[1].int().unwrap())), c, metac },
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PrimCombI::Minus => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() - ps[1].int().unwrap())), c, metac },
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PrimCombI::Mult => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() * ps[1].int().unwrap())), c, metac },
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PrimCombI::Div => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() / ps[1].int().unwrap())), c, metac },
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PrimCombI::Mod => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() % ps[1].int().unwrap())), c, metac },
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PrimCombI::And => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() & ps[1].int().unwrap())), c, metac },
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PrimCombI::Or => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() | ps[1].int().unwrap())), c, metac },
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PrimCombI::Xor => Cursor { f: Rc::new(Form::Int(ps[0].int().unwrap() ^ ps[1].int().unwrap())), c, metac },
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PrimCombI::CombP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::PrimComb { .. } => true,
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Form::DeriComb { .. } => true,
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_ => false,
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})), c, metac },
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PrimCombI::CellP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::Cell(_c) => true,
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_ => false,
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})), c, metac },
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PrimCombI::PairP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::Pair(_a,_b) => true,
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_ => false,
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})), c, metac },
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PrimCombI::SymbolP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::Symbol(_) => true,
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_ => false,
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})), c, metac },
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PrimCombI::IntP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::Int(_) => true,
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_ => false,
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})), c, metac },
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PrimCombI::BoolP => Cursor { f: Rc::new(Form::Bool(match &*ps[0] {
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Form::Bool(_) => true,
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_ => false,
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})), c, metac },
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PrimCombI::NilP => Cursor { f: Rc::new(Form::Bool(ps[0].is_nil())), c, metac },
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}
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}
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}
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fn assoc(k: &str, v: Rc<Form>, l: Rc<Form>) -> Rc<Form> {
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Rc::new(Form::Pair(
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Rc::new(Form::Pair(
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Rc::new(Form::Symbol(k.to_owned())),
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v)),
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l))
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}
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pub fn assoc_vec(kvs: Vec<(&str, Rc<Form>)>) -> Rc<Form> {
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let mut to_ret = Rc::new(Form::Nil);
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for (k, v) in kvs {
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to_ret = assoc(k, v, to_ret);
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}
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to_ret
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}
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// Have eval?/maybe Cont?/maybe Cursor? parameterized on value type?
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// Parameterized on prim implementation?
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// Should opt impl use same prim implementation but trace values through accessors/constructors?
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// with some special handling of If/Vau/etc?
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pub fn root_env() -> Rc<Form> {
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assoc_vec(vec![
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("eval", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Eval })),
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("vau", Rc::new(Form::PrimComb { eval_limit: 0, ins: PrimCombI::Vau })),
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("if", Rc::new(Form::PrimComb { eval_limit: 1, ins: PrimCombI::If })),
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("reset", Rc::new(Form::PrimComb { eval_limit: 0, ins: PrimCombI::Reset })),
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("shift", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Shift })),
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("cell", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Cell })),
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("set", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Set })),
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("get", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Get })),
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("cons", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Cons })),
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("car", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Car })),
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("cdr", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Cdr })),
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("quote", Rc::new(Form::PrimComb { eval_limit: 0, ins: PrimCombI::Quote })),
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("assert", Rc::new(Form::PrimComb { eval_limit: 1, ins: PrimCombI::Assert })),
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("=", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Eq })),
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("<", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Lt })),
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("<=", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::LEq })),
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(">", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Gt })),
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(">=", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::GEq })),
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("+", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Plus })),
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("-", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Minus })),
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("*", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Mult })),
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("/", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Div })),
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("%", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Mod })),
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("&", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::And })),
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("|", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Or })),
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("^", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::Xor })),
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("comb?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::CombP })),
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("cell?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::CellP })),
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("pair?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::PairP })),
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("symbol?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::SymbolP })),
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("int?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::IntP })),
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("bool?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::BoolP })),
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("nil?", Rc::new(Form::PrimComb { eval_limit: -1, ins: PrimCombI::NilP })),
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("true", Rc::new(Form::Bool(true))),
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("false", Rc::new(Form::Bool(false))),
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("nil", Rc::new(Form::Nil)),
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])
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}
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