Switch export snippet to use exit matchers.

src/parser/export_snippet.rs

@@ -1,8 +1,6 @@
-use nom::branch::alt;
 use nom::bytes::complete::tag;
 use nom::character::complete::anychar;
 use nom::combinator::opt;
-use nom::combinator::peek;
 use nom::combinator::recognize;
 use nom::combinator::verify;
 use nom::multi::many1;
@@ -11,6 +9,9 @@ use nom::sequence::tuple;
 
 use super::Context;
 use crate::error::Res;
+use crate::parser::exiting::ExitClass;
+use crate::parser::parser_context::ContextElement;
+use crate::parser::parser_context::ExitMatcherNode;
 use crate::parser::parser_with_context::parser_with_context;
 use crate::parser::util::exit_matcher_parser;
 use crate::parser::util::get_consumed;
@@ -23,8 +24,15 @@ pub fn export_snippet<'r, 's>(
 ) -> Res<&'s str, ExportSnippet<'s>> {
     let (remaining, _) = tag("@@")(input)?;
     let (remaining, backend_name) = backend(context, remaining)?;
-    let (remaining, backend_contents) =
-        opt(tuple((tag(":"), parser_with_context!(contents)(context))))(remaining)?;
+    let parser_context =
+        context.with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
+            class: ExitClass::Beta,
+            exit_matcher: &export_snippet_end,
+        }));
+    let (remaining, backend_contents) = opt(tuple((
+        tag(":"),
+        parser_with_context!(contents)(&parser_context),
+    )))(remaining)?;
     let (remaining, _) = tag("@@")(remaining)?;
     let source = get_consumed(input, remaining);
     Ok((
@@ -48,14 +56,13 @@ fn backend<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn contents<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let (remaining, source) = recognize(verify(
-        many_till(
-            anychar,
-            peek(alt((
-                parser_with_context!(exit_matcher_parser)(context),
-                tag("@@"),
-            ))),
-        ),
+        many_till(anychar, parser_with_context!(exit_matcher_parser)(context)),
         |(children, _exit_contents)| !children.is_empty(),
     ))(input)?;
     Ok((remaining, source))
 }
+
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
+fn export_snippet_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    tag("@@")(input)
+}