some more usability improvements

crates/treehouse-format/src/ast.rs

@@ -1,7 +1,7 @@
 use std::ops::Range;
 
 use crate::{
-    pull::{BranchEvent, BranchKind, Parser},
+    pull::{Attributes, BranchEvent, BranchKind, Parser},
     ParseError, ParseErrorKind,
 };
 
@@ -26,7 +26,7 @@ impl Roots {
 #[derive(Debug, Clone)]
 pub struct Branch {
     pub indent_level: usize,
-    pub attributes: Range<usize>,
+    pub attributes: Option<Attributes>,
     pub kind: BranchKind,
     pub kind_span: Range<usize>,
     pub content: Range<usize>,

crates/treehouse-format/src/pull.rs

@@ -25,7 +25,13 @@ pub struct BranchEvent {
     pub kind: BranchKind,
     pub kind_span: Range<usize>,
     pub content: Range<usize>,
-    pub attributes: Range<usize>,
+    pub attributes: Option<Attributes>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Attributes {
+    pub percent: Range<usize>,
+    pub data: Range<usize>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -100,11 +106,15 @@ impl<'a> Parser<'a> {
         let attributes = if self.current() == Some('%') {
             let start = self.position;
             self.advance();
+            let after_percent = self.position;
             self.eat_indented_lines_until(indent_level, |c| c == '-' || c == '+')?;
             let end = self.position;
-            start..end
+            Some(Attributes {
+                percent: start..after_percent,
+                data: after_percent..end,
+            })
         } else {
-            self.position..self.position
+            None
         };
 
         let kind_start = self.position;