First steps for the macro system

orchid-base/src/tree.rs

@@ -16,7 +16,7 @@ use crate::error::OrcErrv;
 use crate::format::{FmtCtx, FmtUnit, Format, Variants};
 use crate::interner::{Interner, Tok};
 use crate::location::{Pos, SrcRange};
-use crate::name::Sym;
+use crate::name::{Sym, VName, VPath};
 use crate::parse::Snippet;
 use crate::{api, match_mapping, tl_cache};
 
@@ -149,6 +149,20 @@ impl<H: ExprRepr, X: ExtraTok> TokTree<H, X> {
 	pub fn as_name(&self) -> Option<Tok<String>> {
 		if let Token::Name(n) = &self.tok { Some(n.clone()) } else { None }
 	}
+	pub fn as_multiname(&self) -> Result<VName, &TokTree<H, X>> {
+		let mut segs = VPath::new([]);
+		let mut cur = self;
+		loop {
+			match &cur.tok {
+				Token::Name(last) => return Ok(segs.name_with_suffix(last.clone())),
+				Token::NS(seg, inner) => {
+					segs = segs.suffix([seg.clone()]);
+					cur = inner;
+				},
+				_ => return Err(cur),
+			}
+		}
+	}
 	pub fn as_s(&self, par: Paren) -> Option<Snippet<'_, H, X>> {
 		self.tok.as_s(par).map(|slc| Snippet::new(self, slc))
 	}