commit before easter break

orchid-std/src/macros/mactree_lexer.rs

@@ -0,0 +1,64 @@
+use std::ops::RangeInclusive;
+use std::rc::Rc;
+
+use futures::FutureExt;
+use orchid_base::error::{OrcRes, mk_errv};
+use orchid_base::location::Pos;
+use orchid_base::parse::name_start;
+use orchid_base::tokens::PARENS;
+use orchid_extension::atom::AtomicFeatures;
+use orchid_extension::gen_expr::atom;
+use orchid_extension::lexer::{LexContext, Lexer, err_not_applicable};
+use orchid_extension::tree::{GenTok, GenTokTree};
+
+use crate::macros::mactree::{MacTok, MacTree};
+
+#[derive(Default)]
+pub struct MacTreeLexer;
+impl Lexer for MacTreeLexer {
+	const CHAR_FILTER: &'static [RangeInclusive<char>] = &['\''..='\''];
+	async fn lex<'a>(tail: &'a str, ctx: &'a LexContext<'a>) -> OrcRes<(&'a str, GenTokTree<'a>)> {
+		let Some(tail2) = tail.strip_prefix('\'') else {
+			return Err(err_not_applicable(ctx.i).await.into());
+		};
+		let tail3 = tail2.trim_start();
+		return match mac_tree(tail3, ctx).await {
+			Ok((tail4, mactree)) =>
+				Ok((tail4, GenTok::X(mactree.factory()).at(ctx.pos(tail)..ctx.pos(tail4)))),
+			Err(e) => Ok((tail2, GenTok::Bottom(e).at(ctx.tok_ran(1, tail2)))),
+		};
+		async fn mac_tree<'a>(tail: &'a str, ctx: &'a LexContext<'a>) -> OrcRes<(&'a str, MacTree)> {
+			for (lp, rp, paren) in PARENS {
+				let Some(mut body_tail) = tail.strip_prefix(*lp) else { continue };
+				let mut items = Vec::new();
+				return loop {
+					let tail2 = body_tail.trim();
+					if let Some(tail3) = tail2.strip_prefix(*rp) {
+						break Ok((tail3, MacTree {
+							pos: Pos::Range(ctx.pos(tail)..ctx.pos(tail3)),
+							tok: Rc::new(MacTok::S(*paren, items)),
+						}));
+					} else if tail2.is_empty() {
+						return Err(mk_errv(
+							ctx.i.i("Unclosed block").await,
+							format!("Expected closing {rp}"),
+							[Pos::Range(ctx.tok_ran(1, tail)).into()],
+						));
+					}
+					let (new_tail, new_item) = mac_tree(tail2, ctx).boxed_local().await?;
+					body_tail = new_tail;
+					items.push(new_item);
+				};
+			}
+			const INTERPOL: &[&str] = &["$", "..$"];
+			for pref in INTERPOL {
+				let Some(code) = tail.strip_prefix(pref) else { continue };
+			}
+			return Err(mk_errv(
+				ctx.i.i("Expected token after '").await,
+				format!("Expected a token after ', found {tail:?}"),
+				[Pos::Range(ctx.tok_ran(1, tail)).into()],
+			));
+		}
+	}
+}