Macro system done in theory

too afraid to begin debugging, resting for a moment

orchid-std/src/macros/resolve.rs

@@ -0,0 +1,107 @@
+use futures::FutureExt;
+use hashbrown::HashMap;
+use itertools::Itertools;
+use orchid_base::error::mk_errv;
+use orchid_base::location::Pos;
+use orchid_base::name::Sym;
+use orchid_base::sym;
+use orchid_base::tree::Paren;
+use orchid_extension::conv::ToExpr;
+use orchid_extension::coroutine_exec::ExecHandle;
+use orchid_extension::gen_expr::{GExpr, bot, call, sym_ref};
+use orchid_extension::system::SysCtx;
+
+use crate::macros::macro_line::{Macro, Rule};
+use crate::macros::recur_state::{RecurState, RulePath};
+use crate::macros::rule::matcher::{NamedMatcher, PriodMatcher};
+use crate::macros::rule::state::{MatchState, StateEntry};
+use crate::{MacTok, MacTree};
+
+pub struct ResolveCtx<'a> {
+	pub ctx: SysCtx,
+	pub recur: RecurState,
+	pub h: ExecHandle<'a>,
+	pub named: HashMap<Sym, Vec<(&'a NamedMatcher, &'a Macro, &'a Rule)>>,
+	pub priod: Vec<(&'a PriodMatcher, &'a Macro, &'a Rule)>,
+}
+
+pub async fn resolve(ctx: &mut ResolveCtx<'_>, value: &MacTree) -> Option<MacTree> {
+	match value.tok() {
+		MacTok::Ph(_) | MacTok::Slot => panic!("Forbidden element in value mactree"),
+		MacTok::Bottom(_) | MacTok::Value(_) | MacTok::Name(_) => None,
+		MacTok::Lambda(arg, body) =>
+			Some(MacTok::Lambda(arg.clone(), resolve_seq(ctx, body).await?).at(value.pos())),
+		MacTok::S(ptyp, body) => Some(MacTok::S(*ptyp, resolve_seq(ctx, body).await?).at(value.pos())),
+	}
+}
+
+pub async fn resolve_seq(ctx: &mut ResolveCtx<'_>, val: &[MacTree]) -> Option<Vec<MacTree>> {
+	let mut any_changed = false;
+	let mut i = 0;
+	let mut val = val.to_vec();
+	while i < val.len() {
+		let MacTok::Name(key) = val[i].tok() else { continue };
+		let Some(options) = ctx.named.get(key) else { continue };
+		let matches = (options.iter())
+			.filter_map(|r| Some((r.1, r.2, r.0.apply(&val[i..], |_| false)?)))
+			.collect_vec();
+		match matches.len() {
+			0 => i += 1,
+			1 => {
+				any_changed = true;
+				let (mac, rule, (state, tail)) = matches.into_iter().exactly_one().unwrap();
+				let end = val.len() - tail.len();
+				let new_i = val.len() - tail.len();
+				let body_call = mk_body_call(mac, rule, &state, &ctx.ctx, ctx.recur.clone()).await;
+				std::mem::drop(state);
+				val.splice(i..end, [MacTok::Value(ctx.h.register(body_call).await).at(Pos::None)]);
+				i = new_i;
+			},
+			2.. => todo!("Named macros conflict!"),
+		}
+	}
+	for (matcher, mac, rule) in &ctx.priod {
+		let Some(state) = matcher.apply(&val, |_| false) else { continue };
+		return Some(vec![
+			MacTok::Value(
+				ctx.h.register(mk_body_call(mac, rule, &state, &ctx.ctx, ctx.recur.clone()).await).await,
+			)
+			.at(Pos::None),
+		]);
+	}
+	for expr in val.iter_mut() {
+		if let Some(new) = resolve(ctx, expr).boxed_local().await {
+			*expr = new;
+			any_changed = true;
+		}
+	}
+	if any_changed { Some(val) } else { None }
+}
+
+async fn mk_body_call(
+	mac: &Macro,
+	rule: &Rule,
+	state: &MatchState<'_>,
+	ctx: &SysCtx,
+	recur: RecurState,
+) -> GExpr {
+	let rule_path =
+		RulePath { module: mac.0.module.clone(), main_kw: mac.0.own_kws[0].clone(), rule: rule.index };
+	let Some(new_recur) = recur.push(rule_path.clone()) else {
+		return bot(mk_errv(
+			ctx.i().i("Circular macro dependency").await,
+			format!("The definition of {rule_path} is circular"),
+			[rule.pos.clone()],
+		));
+	};
+	let mut call_args = vec![sym_ref(mac.0.module.suffix([rule.body_name.clone()], ctx.i()).await)];
+	for name in rule.placeholders.iter() {
+		call_args.push(match state.get(name).expect("Missing state entry for placeholder") {
+			StateEntry::Scalar(scal) => (**scal).clone().to_expr().await,
+			StateEntry::Vec(vec) => MacTok::S(Paren::Round, vec.to_vec()).at(Pos::None).to_expr().await,
+		});
+	}
+	call_args
+		.push(call([sym_ref(sym!(macros::resolve_recur; ctx.i()).await), new_recur.to_expr().await]));
+	call(call_args)
+}