Support detecting line indentation when checking for contentless plain list items.

org_mode_samples/greater_element/plain_list/description_list.org

@@ -9,3 +9,6 @@
 - big gap ::
 
   stuff
+- empty value with blank ::
+
+stuff

src/parser/plain_list.rs

@@ -168,9 +168,20 @@ fn plain_list_item<'b, 'g, 'r, 's>(
     let (remaining, maybe_tag) =
         opt(tuple((space1, parser_with_context!(item_tag)(context))))(remaining)?;
 
+    let exit_matcher = plain_list_item_end(indent_level);
+    let contexts = [
+        ContextElement::ConsumeTrailingWhitespace(true),
+        ContextElement::ExitMatcherNode(ExitMatcherNode {
+            class: ExitClass::Beta,
+            exit_matcher: &exit_matcher,
+        }),
+    ];
+    let parser_context = context.with_additional_node(&contexts[0]);
+    let parser_context = parser_context.with_additional_node(&contexts[1]);
+
     let maybe_contentless_item: Res<OrgSource<'_>, ()> = peek(parser_with_context!(
         detect_contentless_item_contents
-    )(context))(remaining);
+    )(&parser_context))(remaining);
     match maybe_contentless_item {
         Ok((_rem, _ws)) => {
             let (remaining, _trailing_ws) = opt(blank_line)(remaining)?;
@@ -191,17 +202,7 @@ fn plain_list_item<'b, 'g, 'r, 's>(
         }
         Err(_) => {}
     };
-    let (remaining, _ws) = item_tag_post_gap(context, remaining)?;
+    let (remaining, _ws) = item_tag_post_gap(&parser_context, remaining)?;
-    let exit_matcher = plain_list_item_end(indent_level);
-    let contexts = [
-        ContextElement::ConsumeTrailingWhitespace(true),
-        ContextElement::ExitMatcherNode(ExitMatcherNode {
-            class: ExitClass::Beta,
-            exit_matcher: &exit_matcher,
-        }),
-    ];
-    let parser_context = context.with_additional_node(&contexts[0]);
-    let parser_context = parser_context.with_additional_node(&contexts[1]);
 
     let (mut remaining, (mut children, _exit_contents)) = many_till(
         include_input(parser_with_context!(element(true))(&parser_context)),