Improve Level API a bit

Author: GuillaumeGomez

rinja_parser/src/lib.rs

@@ -635,14 +635,17 @@ impl<'a> State<'a> {
         }
     }
 
-    fn nest<'b>(&self, i: &'b str) -> ParseResult<'b, ()> {
-        let (_, level) = self.level.get().nest(i)?;
+    fn nest<'b, T, F: FnOnce(&'b str) -> ParseResult<'b, T>>(
+        &self,
+        i: &'b str,
+        mut callback: F,
+    ) -> ParseResult<'b, T> {
+        let prev_level = self.level.get();
+        let (_, level) = prev_level.nest(i)?;
         self.level.set(level);
-        Ok((i, ()))
-    }
-
-    fn leave(&self) {
-        self.level.set(self.level.get().leave());
+        let ret = callback(i);
+        self.level.set(prev_level);
+        ret
     }
 
     fn tag_block_start<'i>(&self, i: &'i str) -> ParseResult<'i> {
@@ -720,10 +723,6 @@ impl Level {
         Ok((i, Level(self.0 + 1)))
     }
 
-    fn leave(&self) -> Self {
-        Level(self.0 - 1)
-    }
-
     const MAX_DEPTH: u8 = 128;
 }
 

rinja_parser/src/node.rs

@@ -90,10 +90,7 @@ impl<'a> Node<'a> {
             }
         };
 
-        let (i, _) = s.nest(j)?;
-        let result = func(i, s);
-        s.leave();
-        let (i, node) = result?;
+        let (i, node) = s.nest(j, |i| func(i, s))?;
 
         let (i, closed) = cut(alt((
             value(true, |i| s.tag_block_end(i)),
@@ -197,12 +194,7 @@ impl<'a> Target<'a> {
     /// Parses multiple targets with `or` separating them
     pub(super) fn parse(i: &'a str, s: &State<'_>) -> ParseResult<'a, Self> {
         map(
-            separated_list1(ws(tag("or")), |i| {
-                s.nest(i)?;
-                let ret = Self::parse_one(i, s)?;
-                s.leave();
-                Ok(ret)
-            }),
+            separated_list1(ws(tag("or")), |i| s.nest(i, |i| Self::parse_one(i, s))),
             |mut opts| match opts.len() {
                 1 => opts.pop().unwrap(),
                 _ => Self::OrChain(opts),