Implement a parser for a bullet in a list item.

src/parser/plain_list.rs

@@ -1,4 +1,12 @@
+use nom::branch::alt;
+use nom::bytes::complete::tag;
+use nom::character::complete::digit1;
+use nom::character::complete::one_of;
+use nom::combinator::recognize;
+use nom::sequence::tuple;
+
 use super::error::Res;
+use super::token::ListItem;
 use super::token::PlainList;
 use super::Context;
 
@@ -6,3 +14,21 @@ pub fn plain_list<'r, 's>(context: Context<'r, 's>, i: &'s str) -> Res<&'s str,
     // todo
     todo!()
 }
+
+fn item<'r, 's>(context: Context<'r, 's>, i: &'s str) -> Res<&'s str, ListItem<'s>> {
+    // todo
+    todo!()
+}
+
+fn counter<'s>(i: &'s str) -> Res<&'s str, &'s str> {
+    alt((recognize(one_of("abcdefghijklmnopqrstuvwxyz")), digit1))(i)
+}
+
+fn bullet<'s>(i: &'s str) -> Res<&'s str, &'s str> {
+    alt((
+        tag("*"),
+        tag("-"),
+        tag("+"),
+        recognize(tuple((counter, alt((tag("."), tag(")")))))),
+    ))(i)
+}