Files
kraken/slj/src/lib.rs

946 lines
42 KiB
Rust

use std::rc::Rc;
use std::collections::{BTreeSet,BTreeMap};
use std::fmt;
use anyhow::{anyhow,bail,Result};
// This first Simple Lisp really is
//
// No fexprs, no mutation, no continuations, no macros, no strings.
// Int/Bool/Nil/Pair/Symbol/Closure/Prim.
//
// Figuring out GC between a JIT and Rust will be tricky.
// Can start with a like tracing-JIT-into-bytecode
// let's make our own Box, Rc, maybe Arc, Vec too?
// rustonomicon
#[derive(Debug, Eq, PartialEq, Ord, PartialOrd, Clone, Copy)]
pub struct ID {
id: i64
}
impl fmt::Display for ID {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.id)
}
}
#[derive(Debug)]
pub enum Form {
Nil,
Int(i32),
Bool(bool),
Symbol(String),
Pair(Rc<Form>, Rc<Form>),
Closure(Vec<String>, Rc<Form>, Rc<Form>, ID),
Prim(Prim),
}
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum Prim {
Add,
Sub,
Mul,
Div,
Mod,
Eq,
Cons,
Car,
Cdr,
}
impl Prim {
fn two_params(self) -> bool {
match self {
Prim::Car | Prim::Cdr => false,
_ => true,
}
}
}
fn eval_prim(f: Prim, b: Rc<Form>, a: Option<Rc<Form>>) -> Result<Rc<Form>> {
Ok(match f {
Prim::Car => b.car()?,
Prim::Cdr => b.cdr()?,
_ => {
let a = a.unwrap();
match f {
Prim::Add => Form::new_int(a.int()? + b.int()?),
Prim::Sub => Form::new_int(a.int()? - b.int()?),
Prim::Mul => Form::new_int(a.int()? * b.int()?),
Prim::Div => Form::new_int(a.int()? / b.int()?),
Prim::Mod => Form::new_int(a.int()? % b.int()?),
Prim::Cons => Form::new_pair(a, b),
Prim::Eq => Form::new_bool(a.my_eq(&b)),
_ => unreachable!(),
}
}
})
}
impl Form {
fn my_eq(&self, o: &Rc<Form>) -> bool {
match self {
Form::Nil => o.is_nil(),
Form::Int(i) => if let Ok(oi) = o.int() { *i == oi } else { false },
Form::Bool(b) => if let Ok(ob) = o.bool() { *b == ob } else { false },
Form::Symbol(s) => if let Ok(os) = o.sym() { s == os } else { false },
Form::Pair(a,b) => if let Ok((oa,ob)) = o.pair() { a.my_eq(&oa) && b.my_eq(&ob) } else { false },
Form::Closure(_, _, _, _) => false,
Form::Prim(p) => match &**o { Form::Prim(op) => p == op, _ => false },
}
}
pub fn new_pair(car: Rc<Form>, cdr: Rc<Form>) -> Rc<Form> {
Rc::new(Form::Pair(car, cdr))
}
pub fn new_nil() -> Rc<Form> {
Rc::new(Form::Nil)
}
pub fn new_int(i: i32) -> Rc<Form> {
Rc::new(Form::Int(i))
}
pub fn new_bool(b: bool) -> Rc<Form> {
Rc::new(Form::Bool(b))
}
fn new_closure(params: Vec<String>, env: Rc<Form>, body: Rc<Form>, ctx: &mut Ctx) -> Rc<Form> {
Rc::new(Form::Closure(params, env, body, ctx.alloc_id()))
}
fn truthy(&self) -> bool {
match self {
Form::Bool(b) => *b,
Form::Nil => false,
_ => true,
}
}
fn bool(&self) -> Result<bool> {
match self {
Form::Bool(b) => Ok(*b),
_ => Err(anyhow!("bool on not a bool")),
}
}
fn int(&self) -> Result<i32> {
match self {
Form::Int(i) => Ok(*i),
_ => Err(anyhow!("int on not a int")),
}
}
fn prim(&self) -> Result<Prim> {
match self {
Form::Prim(p) => Ok(*p),
_ => Err(anyhow!("prim on not a prim")),
}
}
fn sym(&self) -> Result<&str> {
match self {
Form::Symbol(s) => Ok(s),
_ => Err(anyhow!("sym on not a sym")),
}
}
fn pair(&self) -> Result<(Rc<Form>,Rc<Form>)> {
match self {
Form::Pair(car, cdr) => Ok((Rc::clone(car),Rc::clone(cdr))),
_ => Err(anyhow!("pair on not a pair {self}")),
}
}
fn car(&self) -> Result<Rc<Form>> {
match self {
Form::Pair(car, _cdr) => Ok(Rc::clone(car)),
_ => Err(anyhow!("car on not a pair")),
}
}
fn cdr(&self) -> Result<Rc<Form>> {
match self {
Form::Pair(_car, cdr) => Ok(Rc::clone(cdr)),
_ => Err(anyhow!("cdr on not a pair")),
}
}
fn is_nil(&self) -> bool {
match self {
Form::Nil => true,
_ => false,
}
}
pub fn append(&self, x: Rc<Form>) -> Result<Rc<Form>> {
match self {
Form::Pair(car, cdr) => cdr.append(x).map(|x| Rc::new(Form::Pair(Rc::clone(car), x))),
Form::Nil => Ok(Rc::new(Form::Pair(x, Rc::new(Form::Nil)))),
_ => Err(anyhow!("append to not a pair")),
}
}
pub fn root_env() -> Rc<Form> {
let mut e = Form::new_nil();
for (s, v) in [
("+", Rc::new(Form::Prim(Prim::Add))),
("-", Rc::new(Form::Prim(Prim::Sub))),
("*", Rc::new(Form::Prim(Prim::Mul))),
("/", Rc::new(Form::Prim(Prim::Div))),
("%", Rc::new(Form::Prim(Prim::Mod))),
("cons", Rc::new(Form::Prim(Prim::Cons))),
("cdr", Rc::new(Form::Prim(Prim::Cdr))),
("car", Rc::new(Form::Prim(Prim::Car))),
("=", Rc::new(Form::Prim(Prim::Eq))),
("nil", Form::new_nil()),
] {
e = e.define(s.to_string(), v);
}
e
}
pub fn lookup(self: &Rc<Self>, s: &str) -> Result<Rc<Form>> {
let mut e = Rc::clone(self);
loop {
let (kv, ne) = e.pair()?;
let (sp, v) = kv.pair()?;
if sp.sym()? == s {
return Ok(v);
}
e = ne;
}
}
pub fn define(self: &Rc<Self>, s: String, v: Rc<Form>) -> Rc<Form> {
Form::new_pair(Form::new_pair(Rc::new(Form::Symbol(s)), v), Rc::clone(self))
}
}
// JIT Decisions
// JIT Closure vs JIT Closure-Template
// That is, do you treat the closed-over variables as constant
// currently we do! if a lookup is not to one of our in-func defined variables, it's a
// constant. done in trace_lookup
// Or maybe more specifically, which closed over variables do you treat as constant
// This will later inform optimistic inlining of primitives, I imagine
// Inline or not
// Rejoin branches or not
// currently we trace into extended basic blocks, in the future stitch those together + const
// prop to do more standard traces (after longer warm-up)
//
// currently we basically just have lazy EBB bytecode construction
// which I like!
impl fmt::Display for Op {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Op::Guard { const_value, side_val:_, side_cont:_, side_id, tbk:_ } => write!(f, "Guard{side_id}({const_value})"),
Op::Debug => write!(f, "Debug"),
Op::Define { sym } => write!(f, "Define({sym})"),
Op::Const ( con ) => write!(f, "Const_{con}"),
Op::Drop => write!(f, "Drop"),
Op::Lookup { sym } => write!(f, "Lookup({sym})"),
Op::Call { len, nc:_, nc_id, statik } => write!(f, "Call{nc_id}({len},{statik:?})"),
Op::InlinePrim(prim) => write!(f, "{prim:?}"),
Op::Tail(len,oid) => write!(f, "Tail({len},{oid:?})"),
Op::Return => write!(f, "Return"),
}
}
}
impl Op {
fn cnst(&self) -> Result<Rc<Form>> {
match self {
Op::Const(c) => Ok(Rc::clone(c)),
_ => Err(anyhow!("const on not a const")),
}
}
}
#[derive(Debug,Clone)]
struct TraceBookkeeping {
func_id: ID,
stack_const: Vec<bool>,
defined_names: BTreeSet<String>,
}
#[derive(Debug)]
enum Op {
Guard { const_value: Rc<Form>, side_val: Option<Rc<Form>>, side_cont: Rc<Cont>, side_id: ID, tbk: TraceBookkeeping },
Debug,
Define { sym: String },
Const ( Rc<Form> ),
Drop,
Lookup { sym: String },
Call { len: usize, statik: Option<ID>, nc: Rc<Cont>, nc_id: ID },
InlinePrim(Prim),
Tail(usize,Option<ID>),
Return,
}
#[derive(Debug)]
struct Trace {
id: ID,
ops: Vec<Op>,
tbk: TraceBookkeeping,
}
impl Trace {
fn new(id: ID, func_id: ID) -> Self {
Trace { id, ops: vec![], tbk: TraceBookkeeping { stack_const: vec![], defined_names: BTreeSet::new(), func_id } }
}
fn follow_on(id: ID, tbk: TraceBookkeeping) -> Self {
Trace { id, ops: vec![], tbk }
}
}
impl fmt::Display for Trace {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Trace for {} (func {}) [", self.id, self.tbk.func_id)?;
for op in &self.ops {
write!(f, " {}", op)?;
}
write!(f, " ]")?;
if !self.tbk.stack_const.is_empty() {
write!(f, "[")?;
for s in &self.tbk.stack_const {
write!(f, " {}", s)?;
}
write!(f, " ]")?;
}
Ok(())
}
}
#[derive(Debug)]
struct Ctx {
id_counter: i64,
cont_count: BTreeMap<ID, i64>,
tracing: Option<Trace>,
traces: BTreeMap<ID, Trace>,
trace_resume_data: BTreeMap<ID, TraceBookkeeping>,
}
impl fmt::Display for Ctx {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Ctx")
}
}
impl Ctx {
fn new() -> Ctx {
Ctx {
id_counter: 0,
cont_count: BTreeMap::new(),
tracing: None,
traces: BTreeMap::new(),
trace_resume_data: BTreeMap::new(),
}
}
fn alloc_id(&mut self) -> ID {
self.id_counter += 1;
ID { id: self.id_counter }
}
fn trace_running(&self) -> bool { self.tracing.is_some() }
// Though I guess that means call start should recieve the parameters
// also, for like variables, it should guard on what function
// if dynamic, interacts with the constant tracking
// 8 options
// - not tracing, closure - do stats
// - not tracing, prim - do nothing
// - tracing, Static Prim - inline prim
// - tracing, Static non-self - inline call? (currently static call)
// - tracing, Static, tail-self - emit tail (static) (we removed loop because it's a static jump back to the head trace regardless)
// - tracing, Static,nontail-self- emit call (static)
// - tracing, Dynamic, tail - emit tail
// - tracing, Dynamic, non-tail - emit call
fn trace_call(&mut self, call_len: usize, tmp_stack: &Vec<Rc<Form>>, nc: &Rc<Cont>) -> Option<ID> {
// Needs to take and use parameters for mid-trace
// needs to guard on function called if non-constant
println!("trace_call call_len={call_len},trace={:?}, tmp_stack {tmp_stack:?}", self.tracing);
if let Some(trace) = &mut self.tracing {
let statik = if trace.tbk.stack_const[trace.tbk.stack_const.len()-call_len] {
// const - TODO: for now, we don't inline but we will want to later (based on what
// metrics? can we run them simultaniously, heirarchially? with our new approach on
// prims maybe (heck we may need to go farther, and remove the InlinePrim!)
match &*tmp_stack[tmp_stack.len()-call_len] {
Form::Prim(p) => {
if (&trace.tbk.stack_const[trace.tbk.stack_const.len()-call_len..]).iter().all(|x| *x) {
trace.tbk.stack_const.truncate(trace.tbk.stack_const.len()-call_len);
let b = trace.ops[trace.ops.len()-1].cnst().unwrap();
let (a,f) = if call_len == 3 {
(Some(trace.ops[trace.ops.len()-2].cnst().unwrap()), p)
} else { (None, p) };
for _ in 0..call_len {
trace.ops.push(Op::Drop);
}
trace.ops.push(Op::Const(eval_prim(*f, b, a).unwrap()));
trace.tbk.stack_const.push(true);
} else {
trace.tbk.stack_const.truncate(trace.tbk.stack_const.len()-call_len);
trace.ops.push(Op::InlinePrim(*p));
trace.tbk.stack_const.push(false);
}
return None;
},
Form::Closure(_ps, _e, _b, id) => {
if nc.is_ret() {
if *id == trace.tbk.func_id {
// we removed the loop opcode because this trace needs to know the
// func header trace id anyway
trace.ops.push(Op::Tail(call_len, Some(*id)));
} else {
// should be inline
trace.ops.push(Op::Tail(call_len, Some(*id)));
}
println!("Ending trace at loop/tail recursive call!");
println!("\t{}", trace);
self.traces.insert(trace.id, self.tracing.take().unwrap());
return None;
}
// fall through to be a static call, though also would normally be inline
Some(*id)
},
b => panic!("bad func {b:?}"),
}
} else { None };
// (normally not const) or has tmps - Call or TailCall
if nc.is_ret() {
trace.ops.push(Op::Tail(call_len,statik));
println!("Ending trace at tail recursive call!");
println!("\t{}", trace);
self.traces.insert(trace.id, self.tracing.take().unwrap());
return None;
} else {
trace.tbk.stack_const.truncate(trace.tbk.stack_const.len()-call_len);
self.id_counter += 1; let nc_id = ID { id: self.id_counter }; // HACK - I can't use the method cuz trace is borrowed
trace.ops.push(Op::Call { len: call_len, statik, nc: Rc::clone(nc), nc_id });
println!("Ending trace at call!");
println!("\t{}", trace);
self.trace_resume_data.insert(nc_id, trace.tbk.clone());
self.traces.insert(trace.id, self.tracing.take().unwrap());
return Some(nc_id);
}
}
None
}
fn trace_frame(&mut self, syms: &Vec<String>, id: ID) {
let inline = self.tracing.is_some();
let entry = self.cont_count.entry(id).or_insert(0);
println!("tracing call start for {id}, has been called {} times so far", *entry);
*entry += 1;
if *entry > 1 && self.tracing.is_none() && self.traces.get(&id).is_none() {
self.tracing = Some(Trace::new(id, id));
}
for s in syms.iter().rev() {
self.trace_define(s, inline);
}
self.trace_drop(inline);
}
fn trace_call_end(&mut self, id: ID, follow_on_trace_data: Option<ID>) {
println!("tracing call end for {id} followon {follow_on_trace_data:?}");
if let Some(trace) = &mut self.tracing {
if trace.tbk.func_id == id {
trace.ops.push(Op::Return);
println!("Ending trace at end of call!");
println!("\t{}", trace);
self.traces.insert(trace.id, self.tracing.take().unwrap());
}
}
if self.tracing.is_none() {
self.try_resume_trace(follow_on_trace_data);
}
}
fn try_resume_trace(&mut self, follow_on_trace_data: Option<ID>) {
if let Some(follow_id) = follow_on_trace_data {
println!("looking follow-on trace {follow_id} in {:?}", self.trace_resume_data);
if let Some(follow_tbk) = self.trace_resume_data.remove(&follow_id) {
println!("starting follow-on trace {follow_id}, {follow_tbk:?}");
let mut trace = Trace::follow_on(follow_id,follow_tbk);
trace.tbk.stack_const.push(false); // fix with actual, if this ends up being a
// static call with static param list that isn't
// inlined for whatever reason...
self.tracing = Some(trace);
}
}
}
fn trace_guard<T: Into<Form> + std::fmt::Debug>(&mut self, value: T, other: impl Fn()->(Option<Rc<Form>>,Rc<Cont>)) {
println!("Tracing guard {value:?}");
if let Some(trace) = &mut self.tracing {
let (side_val, side_cont) = other();
self.id_counter += 1; let side_id = ID { id: self.id_counter }; // HACK - I can't use the method cuz trace is borrowed
trace.ops.push(Op::Guard { const_value: Rc::new(value.into()), side_val, side_cont, side_id, tbk: trace.tbk.clone() });
}
}
fn trace_debug(&mut self) {
if let Some(trace) = &mut self.tracing {
trace.ops.push(Op::Debug);
}
}
fn trace_define(&mut self, sym: &str, pop: bool) {
if let Some(trace) = &mut self.tracing {
trace.ops.push(Op::Define { sym: sym.to_owned() });
trace.tbk.defined_names.insert(sym.to_owned());
if pop {
trace.tbk.stack_const.pop().unwrap();
}
}
}
fn trace_lookup(&mut self, s: &str, f: &Rc<Form>) {
if let Some(trace) = &mut self.tracing {
// constant depends on which env, and I think this is the only spot that cares for
// closure jit vs lambda jit
if trace.tbk.defined_names.contains(s) {
trace.ops.push(Op::Lookup { sym: s.to_owned() });
trace.tbk.stack_const.push(false);
} else {
trace.ops.push(Op::Const(Rc::clone(f)));
trace.tbk.stack_const.push(true);
}
}
}
fn trace_drop(&mut self, pop: bool) {
if let Some(trace) = &mut self.tracing {
trace.ops.push(Op::Drop);
if pop {
trace.tbk.stack_const.pop().unwrap();
}
}
}
fn trace_constant(&mut self, c: &Rc<Form>) {
if let Some(trace) = &mut self.tracing {
trace.ops.push(Op::Const(Rc::clone(c)));
trace.tbk.stack_const.push(true);
}
}
fn trace_lambda(&mut self, _params: &[String], _e: &Rc<Form>, _body: &Rc<Form>) {
if let Some(_trace) = &mut self.tracing {
// TODO
// kinda both also
unimplemented!("trace lambda");
}
}
// returns f, e, c for interp
fn execute_trace_if_exists(&mut self,
id: ID,
e: &Rc<Form>,
tmp_stack: &mut Vec<Rc<Form>>,
ret_stack: &mut Vec<(Rc<Form>, Rc<Cont>, Option<ID>)>) -> Result<Option<(Rc<Form>, Rc<Form>, Cont)>> {
if self.trace_running() {
println!("Not playing back trace because recording trace");
return Ok(None); // can't trace while running a trace for now (we don't inline now anyway),
// in the future it should just tack on the opcodes while jugging the proper
// bookkeeping stacks
}
if let Some(mut trace) = self.traces.get(&id) {
println!("Starting trace playback");
let mut e = Rc::clone(e);
loop {
println!("Running trace {trace}, \n\ttmp_stack:{tmp_stack:?}");
for b in trace.ops.iter() {
match b {
Op::Guard { const_value, side_val, side_cont, side_id, tbk } => {
println!("Guard(op) {const_value}");
if !const_value.my_eq(tmp_stack.last().unwrap()) {
if let Some(new_trace) = self.traces.get(side_id) {
if side_val.is_some() {
tmp_stack.pop().unwrap();
}
println!("\tchaining trace to side trace");
trace = new_trace;
break; // break out of this trace and let infinate loop spin
} else {
println!("\tending playback b/c failed guard");
assert!(self.tracing.is_none());
let mut ntrace = Trace::follow_on(*side_id,tbk.clone());
if let Some(side_val) = side_val {
*tmp_stack.last_mut().unwrap() = Rc::clone(side_val);
*ntrace.tbk.stack_const.last_mut().unwrap() = false; // this might be able to be
// more precise, actually
}
self.tracing = Some(ntrace);
return Ok(Some((tmp_stack.pop().unwrap(), e, (**side_cont).clone())));
}
}
}
Op::Debug => {
println!("Debug(op) {}", tmp_stack.last().unwrap());
}
Op::Define { sym } => {
let v = tmp_stack.pop().unwrap();
println!("Define(op) {sym} = {}", v);
e = e.define(sym.clone(), v);
}
Op::Const ( con ) => {
println!("Const(op) {con}");
tmp_stack.push(Rc::clone(con));
}
Op::Drop => {
println!("Drop(op) {}", tmp_stack.last().unwrap());
tmp_stack.pop().unwrap();
}
Op::Lookup { sym } => {
println!("Lookup(op) {sym}");
tmp_stack.push(e.lookup(sym)?);
}
Op::InlinePrim(prim) => {
println!("InlinePrim(op) {prim:?}");
let b = tmp_stack.pop().unwrap();
let a = if prim.two_params() { Some(tmp_stack.pop().unwrap()) } else { None };
tmp_stack.pop().unwrap(); // pop the prim
tmp_stack.push(eval_prim(*prim, b, a)?);
}
Op::Call { len, nc, nc_id, statik } => {
println!("Call(op)");
if let Some(static_call_id) = statik {
if let Some(new_trace) = self.traces.get(static_call_id) {
ret_stack.push((Rc::clone(&e), (*nc).clone(), Some(*nc_id)));
println!("\tchaining to call trace b/c Call with statik");
trace = new_trace;
break; // break out of this trace and let infinate loop spin
}
}
match &*Rc::clone(&tmp_stack[tmp_stack.len()-*len]) {
Form::Closure(ps, ie, b, call_id) => {
if ps.len() != *len-1 {
bail!("arguments length doesn't match");
}
ret_stack.push((Rc::clone(&e), (*nc).clone(), Some(*nc_id)));
if let Some(new_trace) = self.traces.get(call_id) {
println!("\tchaining to call trace b/c Call with dyamic but traced");
e = Rc::clone(ie);
trace = new_trace;
break; // break out of this trace and let infinate loop spin
} else {
return Ok(Some((Rc::clone(&b), Rc::clone(ie), Cont::Frame { syms: ps.clone(), id: *call_id, c: Rc::new(Cont::Eval { c: Rc::new(Cont::Ret { id: *call_id }) }) })));
}
},
Form::Prim(p) => {
let b = tmp_stack.pop().unwrap();
let a = if *len == 2 { None } else { assert!(*len == 3); Some(tmp_stack.pop().unwrap()) };
let result = eval_prim(*p, b, a)?;
if let Some(new_trace) = self.traces.get(nc_id) {
*tmp_stack.last_mut().unwrap() = result; // for the prim itself
println!("\tchaining to ret trace b/c Call with dyamic but primitive and next traced");
trace = new_trace;
break; // break out of this trace and let infinate loop spin
} else {
println!("\tstopping playback to ret b/c Call with dyamic but primitive and next not-traced");
tmp_stack.pop().unwrap(); // for the prim itself
return Ok(Some((result, e, (**nc).clone())));
}
},
ncomb => {
println!("Current stack is {tmp_stack:?}");
bail!("tried to call a non-comb {ncomb}")
},
}
}
Op::Tail(_len,_oid) => {
println!("Tail(op)");
// Huh, this actually has to know how many envs we pushed on so we can pop
// them off
unimplemented!();
}
Op::Return => {
println!("Return(op)");
let (e, nc, resume_data) = ret_stack.pop().unwrap();
if let Some(resume_id) = resume_data {
if let Some(new_trace) = self.traces.get(&resume_id) {
println!("\tchaining to return trace b/c Return {resume_id} - {new_trace:?}");
trace = new_trace;
break; // break out of this trace and let infinate loop spin
}
}
println!("\tending playback b/c Return, attempting to resume trace");
self.try_resume_trace(resume_data);
return Ok(Some((tmp_stack.pop().unwrap(), e, (*nc).clone())));
}
}
}
}
} else {
Ok(None)
}
}
}
#[derive(Clone,Debug)]
enum Cont {
MetaRet,
Ret { id: ID, },
Eval { c: Rc<Cont> },
Prim { s: &'static str, to_go: Rc<Form>, c: Rc<Cont> },
Call { n: usize, to_go: Rc<Form>, c: Rc<Cont> },
Frame { syms: Vec<String>, id: ID, c: Rc<Cont> },
}
impl Cont {
fn is_ret(&self) -> bool {
match self {
Cont::Ret { id: _ } => true,
_ => false,
}
}
}
pub fn eval(f: Rc<Form>) -> Result<Rc<Form>> {
let mut ctx = Ctx::new();
let mut f = f;
let mut e = Form::root_env();
let mut c = Cont::Eval { c: Rc::new(Cont::MetaRet) };
let mut ret_stack: Vec<(Rc<Form>, Rc<Cont>, Option<ID>)> = vec![];
let mut tmp_stack: Vec<Rc<Form>> = vec![];
loop {
match c {
Cont::MetaRet => {
println!("Ctx was {ctx}");
assert!(!ctx.trace_running());
return Ok(f);
}
Cont::Prim { s, to_go, c: nc } => {
match s {
"if" => {
let thn = to_go.car()?;
let els = to_go.cdr()?.car()?;
if f.truthy() {
ctx.trace_guard(true, || (Some(Rc::clone(&els)), Rc::new(Cont::Eval { c: Rc::clone(&nc) })));
ctx.trace_drop(true);
f = thn;
} else {
ctx.trace_guard(false, ||(Some(Rc::clone(&thn)), Rc::new(Cont::Eval { c: Rc::clone(&nc) })));
ctx.trace_drop(true);
f = els;
}
c = Cont::Eval { c: nc };
},
"or" => {
let other = to_go.car()?;
if !f.truthy() {
ctx.trace_guard(false, || (None, nc.clone()));
ctx.trace_drop(true);
f = other;
c = Cont::Eval { c: nc };
} else {
ctx.trace_guard(true, || (Some(Rc::clone(&other)), Rc::new(Cont::Eval { c: Rc::clone(&nc) })));
c = (*nc).clone();
}
},
"and" => {
let other = to_go.car()?;
if f.truthy() {
ctx.trace_guard(true, || (None, nc.clone()));
ctx.trace_drop(true);
f = other;
c = Cont::Eval { c: nc };
} else {
ctx.trace_guard(false, || (Some(Rc::clone(&other)), Rc::new(Cont::Eval { c: Rc::clone(&nc) })));
c = (*nc).clone();
}
},
"begin" => {
if to_go.is_nil() {
c = (*nc).clone();
} else {
ctx.trace_drop(true);
f = to_go.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "begin", to_go: to_go.cdr()?, c: nc }) };
}
},
"debug" => {
println!("Debug: {f}");
ctx.trace_debug();
c = (*nc).clone();
},
"define" => {
let sym = to_go.sym()?.to_string();
ctx.trace_define(&sym, true);
e = e.define(sym, Rc::clone(&f));
c = (*nc).clone();
},
_ => {
panic!("bad prim {s}");
}
}
},
Cont::Ret { id, } => {
let (ne, nc, resume_data) = ret_stack.pop().unwrap();
ctx.trace_call_end(id, resume_data);
e = ne;
if let Some(nc_id) = resume_data {
tmp_stack.push(f); // ugly dance pt 1
if let Some((fp, ep, cp)) = ctx.execute_trace_if_exists(nc_id, &e, &mut tmp_stack, &mut ret_stack)? {
f = fp;
e = ep;
c = cp;
println!("After executing return trace, f={f}, tmp_stack is {tmp_stack:?}");
continue;
} else {
f = tmp_stack.pop().unwrap(); //ugly dance pt2
}
}
c = (*nc).clone();
},
Cont::Call { n, to_go, c: nc } => {
tmp_stack.push(f);
if to_go.is_nil() {
let resume_data = ctx.trace_call(n, &mut tmp_stack, &nc);
match &*Rc::clone(&tmp_stack[tmp_stack.len()-n]) {
Form::Closure(ps, ie, b, id) => {
if ps.len() != n-1 {
bail!("arguments length doesn't match");
}
ret_stack.push((Rc::clone(&e), nc, resume_data));
if let Some((fp, ep, cp)) = ctx.execute_trace_if_exists(*id, ie, &mut tmp_stack, &mut ret_stack)? {
f = fp;
e = ep;
c = cp;
println!("After executing trace, f={f}, tmp_stack is {tmp_stack:?}");
} else {
println!("replacing {e} with {ie}");
e = Rc::clone(ie);
c = Cont::Frame { syms: ps.clone(), id: *id, c: Rc::new(Cont::Eval { c: Rc::new(Cont::Ret { id: *id }) }) };
f = Rc::clone(&b);
}
},
Form::Prim(p) => {
let b = tmp_stack.pop().unwrap();
let a = if n == 2 { None } else { assert!(n == 3); Some(tmp_stack.pop().unwrap()) };
f = eval_prim(*p, b, a)?;
tmp_stack.pop().unwrap(); // for the prim itself
c = (*nc).clone();
},
ncomb => {
println!("Current stack is {tmp_stack:?}");
bail!("tried to call a non-comb {ncomb}")
},
}
} else {
f = to_go.car()?;
c = Cont::Eval { c: Rc::new(Cont::Call { n: n+1, to_go: to_go.cdr()?, c: nc }) };
}
}
Cont::Frame { syms, id, c: nc } => {
ctx.trace_frame(&syms, id);
for s in syms.into_iter().rev() {
e = e.define(s, tmp_stack.pop().unwrap());
}
tmp_stack.pop().unwrap(); // for the func value
c = (*nc).clone();
}
Cont::Eval { c: nc } => {
let tmp = f;
match &*tmp {
Form::Symbol(s) => {
f = e.lookup(s)?;
ctx.trace_lookup(s, &f);
c = (*nc).clone();
},
Form::Pair(car, cdr) => {
match &**car {
Form::Symbol(s) if s == "if" => {
f = cdr.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "if", to_go: cdr.cdr()?, c: nc }) };
}
// and/or has to short-circut, so special form
// just like Scheme (bad ;) )
Form::Symbol(s) if s == "or" => {
f = cdr.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "or", to_go: cdr.cdr()?, c: nc }) };
}
Form::Symbol(s) if s == "and" => {
f = cdr.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "and", to_go: cdr.cdr()?, c: nc }) };
}
Form::Symbol(s) if s == "begin" => {
f = cdr.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "begin", to_go: cdr.cdr()?, c: nc }) };
}
Form::Symbol(s) if s == "debug" => {
f = cdr.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "debug", to_go: cdr.cdr()?, c: nc }) };
}
Form::Symbol(s) if s == "define" => {
// note the swap, evaluating the second not the first (define a value..)
f = cdr.cdr()?.car()?;
c = Cont::Eval { c: Rc::new(Cont::Prim { s: "define", to_go: cdr.car()?, c: nc }) };
}
Form::Symbol(s) if s == "quote" => {
f = cdr.car()?;
ctx.trace_constant(&f);
c = (*nc).clone();
}
// (lambda (a b) body)
Form::Symbol(s) if s == "lambda" => {
let mut params_vec = vec![];
let mut params = cdr.car()?;
while let Ok((ncar, ncdr)) = params.pair() {
params_vec.push(ncar.sym()?.to_string());
params = ncdr;
}
let body = cdr.cdr()?.car()?;
ctx.trace_lambda(&params_vec, &e, &body);
f = Form::new_closure(params_vec, Rc::clone(&e), body, &mut ctx);
c = (*nc).clone();
}
_ => {
f = Rc::clone(car);
c = Cont::Eval { c: Rc::new(Cont::Call { n: 1, to_go: Rc::clone(cdr), c: nc }) };
}
}
},
_ => {
// value, no eval
f = tmp;
ctx.trace_constant(&f);
c = (*nc).clone();
}
}
}
}
}
}
impl From<String> for Form { fn from(item: String) -> Self { Form::Symbol(item) } }
impl From<&str> for Form { fn from(item: &str) -> Self { Form::Symbol(item.to_owned()) } }
impl From<i32> for Form { fn from(item: i32) -> Self { Form::Int(item) } }
impl From<bool> for Form { fn from(item: bool) -> Self { Form::Bool(item) } }
impl<A: Into<Form>, B: Into<Form>> From<(A, B)> for Form {
fn from(item: (A, B)) -> Self {
Form::Pair(Rc::new(item.0.into()), Rc::new(item.1.into()))
}
}
impl fmt::Display for Form {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Form::Nil => write!(f, "nil"),
Form::Int(i) => write!(f, "{i}"),
Form::Bool(b) => write!(f, "{b}"),
Form::Symbol(s) => write!(f, "'{s}"),
Form::Pair(car, cdr) => {
write!(f, "({}", car)?;
let mut traverse: Rc<Form> = Rc::clone(cdr);
loop {
match &*traverse {
Form::Pair(ref carp, ref cdrp) => {
write!(f, " {}", carp)?;
traverse = Rc::clone(cdrp);
},
Form::Nil => {
write!(f, ")")?;
return Ok(());
},
x => {
write!(f, ". {x})")?;
return Ok(());
},
}
}
},
Form::Closure(params, _inner_env, _code, id) => {
write!(f, "<closure{} {:?}>", id, params)
}
Form::Prim(p) => {
match p {
Prim::Add => write!(f, "+"),
Prim::Sub => write!(f, "-"),
Prim::Mul => write!(f, "*"),
Prim::Div => write!(f, "/"),
Prim::Mod => write!(f, "%"),
Prim::Cons => write!(f, "cons"),
Prim::Car => write!(f, "car"),
Prim::Cdr => write!(f, "cdr"),
Prim::Eq => write!(f, "="),
}
}
}
}
}