commit before easter break

orchid-std/src/macros/mactree.rs

@@ -0,0 +1,75 @@
+use std::borrow::Cow;
+use std::rc::Rc;
+
+use futures::future::join_all;
+use orchid_api::Paren;
+use orchid_base::error::OrcErrv;
+use orchid_base::format::{FmtCtx, FmtUnit, Format, Variants};
+use orchid_base::location::Pos;
+use orchid_base::name::Sym;
+use orchid_base::tl_cache;
+use orchid_base::tree::Ph;
+use orchid_extension::atom::{Atomic, MethodSetBuilder};
+use orchid_extension::atom_owned::{OwnedAtom, OwnedVariant};
+use orchid_extension::expr::Expr;
+
+#[derive(Debug, Clone)]
+pub struct MacTree {
+	pub pos: Pos,
+	pub tok: Rc<MacTok>,
+}
+impl MacTree {}
+impl Atomic for MacTree {
+	type Data = ();
+	type Variant = OwnedVariant;
+}
+impl OwnedAtom for MacTree {
+	type Refs = ();
+
+	async fn val(&self) -> Cow<'_, Self::Data> { Cow::Owned(()) }
+	async fn print<'a>(&'a self, c: &'a (impl FmtCtx + ?Sized + 'a)) -> FmtUnit {
+		self.tok.print(c).await
+	}
+}
+
+#[derive(Debug, Clone)]
+pub enum MacTok {
+	S(Paren, Vec<MacTree>),
+	Name(Sym),
+	/// Only permitted in arguments to `instantiate_tpl`
+	Slot,
+	Value(Expr),
+	Lambda(Vec<MacTree>, Vec<MacTree>),
+	Ph(Ph),
+}
+impl Format for MacTok {
+	async fn print<'a>(&'a self, c: &'a (impl FmtCtx + ?Sized + 'a)) -> FmtUnit {
+		match self {
+			Self::Value(v) => v.print(c).await,
+			Self::Lambda(arg, b) => FmtUnit::new(
+				tl_cache!(Rc<Variants>: Rc::new(Variants::default()
+					.unbounded("\\{0b}.{1l}")
+					.bounded("(\\{0b}.{1b})"))),
+				[mtreev_fmt(arg, c).await, mtreev_fmt(b, c).await],
+			),
+			Self::Name(n) => format!("{n}").into(),
+			Self::Ph(ph) => format!("{ph}").into(),
+			Self::S(p, body) => FmtUnit::new(
+				match *p {
+					Paren::Round => Rc::new(Variants::default().bounded("({0b})")),
+					Paren::Curly => Rc::new(Variants::default().bounded("{{0b}}")),
+					Paren::Square => Rc::new(Variants::default().bounded("[{0b}]")),
+				},
+				[mtreev_fmt(body, c).await],
+			),
+			Self::Slot => format!("SLOT").into(),
+		}
+	}
+}
+
+pub async fn mtreev_fmt<'b>(
+	v: impl IntoIterator<Item = &'b MacTree>,
+	c: &(impl FmtCtx + ?Sized),
+) -> FmtUnit {
+	FmtUnit::sequence(" ", None, join_all(v.into_iter().map(|t| t.print(c))).await)
+}