chore: switch discharge value back to the recursive form for simplicity
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564939ab61
commit
ccc450659a
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@ -1,33 +1,10 @@
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use std::rc::Rc;
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use crate::ast::{NamedDeBruijn, Term};
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use super::value::{Env, Value};
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#[derive(Clone)]
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enum PartialTerm {
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Delay,
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Lambda(Rc<NamedDeBruijn>),
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Apply,
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Force,
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}
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#[derive(Clone)]
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enum DischargeStep {
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DischargeValue(Value),
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DischargeValueEnv(usize, Env, Rc<Term<NamedDeBruijn>>),
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PopArgStack(PartialTerm),
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}
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pub(super) fn value_as_term(value: Value) -> Term<NamedDeBruijn> {
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let mut stack = vec![DischargeStep::DischargeValue(value)];
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let mut arg_stack = vec![];
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while let Some(stack_frame) = stack.pop() {
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match stack_frame {
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DischargeStep::DischargeValue(value) => match value {
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Value::Con(x) => arg_stack.push(Term::Constant(x.clone())),
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match value {
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Value::Con(x) => Term::Constant(x),
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Value::Builtin { runtime, fun } => {
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let mut term = Term::Builtin(fun);
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@ -38,122 +15,73 @@ pub(super) fn value_as_term(value: Value) -> Term<NamedDeBruijn> {
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for arg in runtime.args {
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term = term.apply(value_as_term(arg));
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}
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arg_stack.push(term)
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}
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Value::Delay(body, env) => {
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stack.push(DischargeStep::DischargeValueEnv(
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0,
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env.clone(),
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Term::Delay(body.clone()).into(),
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));
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term
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}
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Value::Delay(body, env) => with_env(0, env, Term::Delay(body)),
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Value::Lambda {
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parameter_name,
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body,
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env,
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} => {
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stack.push(DischargeStep::DischargeValueEnv(
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} => with_env(
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0,
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env.clone(),
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env,
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Term::Lambda {
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parameter_name: parameter_name.clone(),
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body: body.clone(),
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parameter_name: NamedDeBruijn {
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text: parameter_name.text.clone(),
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index: 0.into(),
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}
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.into(),
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));
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}
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body,
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},
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DischargeStep::DischargeValueEnv(lam_cnt, env, term) => match term.as_ref() {
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),
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}
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}
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fn with_env(lam_cnt: usize, env: Env, term: Term<NamedDeBruijn>) -> Term<NamedDeBruijn> {
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match term {
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Term::Var(name) => {
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let index: usize = name.index.into();
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if lam_cnt >= index {
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arg_stack.push(Term::Var(name.clone()));
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Term::Var(name)
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} else {
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let env = env.get::<usize>(env.len() - (index - lam_cnt)).cloned();
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if let Some(v) = env {
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stack.push(DischargeStep::DischargeValue(v));
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} else {
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arg_stack.push(Term::Var(name.clone()));
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}
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env.get::<usize>(env.len() - (index - lam_cnt))
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.cloned()
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.map_or(Term::Var(name), value_as_term)
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}
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}
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Term::Lambda {
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parameter_name,
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body,
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} => {
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stack.push(DischargeStep::PopArgStack(PartialTerm::Lambda(
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parameter_name.to_owned(),
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)));
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stack.push(DischargeStep::DischargeValueEnv(
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lam_cnt + 1,
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env,
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body.to_owned(),
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));
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}
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Term::Apply { function, argument } => {
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stack.push(DischargeStep::PopArgStack(PartialTerm::Apply));
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stack.push(DischargeStep::DischargeValueEnv(
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lam_cnt,
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env.clone(),
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argument.to_owned(),
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));
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stack.push(DischargeStep::DischargeValueEnv(
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lam_cnt,
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env,
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function.to_owned(),
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));
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}
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Term::Delay(body) => {
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stack.push(DischargeStep::PopArgStack(PartialTerm::Delay));
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stack.push(DischargeStep::DischargeValueEnv(
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lam_cnt,
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env.clone(),
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body.to_owned(),
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));
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}
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let body = with_env(lam_cnt + 1, env, body.as_ref().clone());
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Term::Force(body) => {
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stack.push(DischargeStep::PopArgStack(PartialTerm::Force));
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stack.push(DischargeStep::DischargeValueEnv(
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lam_cnt,
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env.clone(),
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body.to_owned(),
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));
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}
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rest => {
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arg_stack.push(rest.to_owned());
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}
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},
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DischargeStep::PopArgStack(term) => match term {
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PartialTerm::Delay => {
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let body = arg_stack.pop().unwrap();
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arg_stack.push(Term::Delay(body.into()))
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}
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PartialTerm::Lambda(parameter_name) => {
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let body = arg_stack.pop().unwrap();
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arg_stack.push(Term::Lambda {
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Term::Lambda {
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parameter_name,
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body: body.into(),
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})
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}
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PartialTerm::Apply => {
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let argument = arg_stack.pop().unwrap();
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let function = arg_stack.pop().unwrap();
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}
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Term::Apply { function, argument } => {
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let function = with_env(lam_cnt, env.clone(), function.as_ref().clone());
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let argument = with_env(lam_cnt, env, argument.as_ref().clone());
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arg_stack.push(function.apply(argument));
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}
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PartialTerm::Force => {
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let body = arg_stack.pop().unwrap();
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arg_stack.push(body.force())
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}
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},
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Term::Apply {
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function: function.into(),
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argument: argument.into(),
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}
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}
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arg_stack.pop().unwrap()
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Term::Delay(x) => {
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let delay = with_env(lam_cnt, env, x.as_ref().clone());
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Term::Delay(delay.into())
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}
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Term::Force(x) => {
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let force = with_env(lam_cnt, env, x.as_ref().clone());
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Term::Force(force.into())
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}
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rest => rest,
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}
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}
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