diff --git a/src/primitives.rs b/src/primitives.rs
index 7fb1243..8af564d 100644
--- a/src/primitives.rs
+++ b/src/primitives.rs
@@ -23,7 +23,7 @@ pub fn literal_char<'a>(expected: char) -> impl Parser<&'a str, char, ()> {
 }
 
 pub fn one_of<'a>(items: &'static str) -> impl Parser<&'a str, char, ()> {
-    move |input: &'a str| {
+    (move |input: &'a str| {
         if let Some(ch) = input.chars().next() {
             if items.contains(ch) {
                 let (_first, rest) = input.split_at(1);
@@ -31,7 +31,16 @@ pub fn one_of<'a>(items: &'static str) -> impl Parser<&'a str, char, ()> {
             }
         }
         Err(((), input))
-    }
+    })
+    .to_anno()
+    .with_repr(
+        Representation::new().with_production(EBNF::Alternation(
+            items
+                .chars()
+                .map(|ch| EBNF::CharTerminal(ch))
+                .collect::<Vec<_>>(),
+        )),
+    )
 }
 
 /// Parses a standard identifier in a programming language
@@ -56,10 +65,22 @@ pub fn identifier(input: &str) -> ParseResult<&str, String, ()> {
     Ok((buf, &input[next_index..]))
 }
 
-pub fn whitespace(input: &str) -> ParseResult<&str, char, ()> {
-    match input.chars().next() {
-        Some(ch) if ch.is_whitespace() => Ok((ch, &input[1..])),
-        _ => Err(((), input)),
+pub struct Whitespace;
+
+impl Parser<&str, char, ()> for Whitespace {
+    fn name(&self) -> Option<String> {
+        Some("whitespace".into())
+    }
+
+    fn representation(&self) -> Representation {
+        Representation::new().with_production(EBNF::LabeledTerminal("whitespace".into()))
+    }
+
+    fn parse<'a>(&self, input: &'a str) -> ParseResult<&'a str, char, ()> {
+        match input.chars().next() {
+            Some(ch) if ch.is_whitespace() => Ok((ch, &input[1..])),
+            _ => Err(((), input)),
+        }
     }
 }
 
@@ -68,11 +89,22 @@ mod tests {
     use super::*;
 
     #[test]
-    fn literals() {
+    fn primitive_parsers() {
         let parser = literal_char('f');
         assert_eq!(Ok(('f', "unky")), parser.parse("funky"));
 
         let repr = parser.representation();
         assert!(matches!(repr.production(), EBNF::CharTerminal('f')));
+
+        let parser = one_of("asdf");
+        let production = parser.representation().production();
+        assert!(
+            matches!(production, EBNF::Alternation(v) if matches!(v.as_slice(), [
+               EBNF::CharTerminal('a'),
+               EBNF::CharTerminal('s'),
+               EBNF::CharTerminal('d'),
+               EBNF::CharTerminal('f'),
+            ]))
+        );
     }
 }
diff --git a/src/representation.rs b/src/representation.rs
index f507817..89c77dd 100644
--- a/src/representation.rs
+++ b/src/representation.rs
@@ -36,6 +36,7 @@ pub enum EBNF {
     Nonterminal(String),
     CharTerminal(char),
     StringTerminal(String),
+    LabeledTerminal(String),
     Alternation(Vec<EBNF>),
 }
 
@@ -55,6 +56,7 @@ impl fmt::Display for EBNF {
             }
             EBNF::Nonterminal(name) => write!(f, "{name}"),
             EBNF::StringTerminal(term) => write!(f, r#""{term}""#),
+            EBNF::LabeledTerminal(s) => write!(f, "<{s}>"),
         }
     }
 }
diff --git a/src/test/sexp.rs b/src/test/sexp.rs
index 52fae60..f4814ad 100644
--- a/src/test/sexp.rs
+++ b/src/test/sexp.rs
@@ -55,7 +55,7 @@ fn parse_list(input: &str) -> ParseResult<&str, Expr, ()> {
     literal_char('(')
         .ignore_then(
             repeated(parse_expr)
-                .separated_by(repeated(whitespace).at_least(1).to(()))
+                .separated_by(repeated(Whitespace).at_least(1).to(()))
                 .allow_trailing(true),
         )
         .then_ignore(literal_char(')'))
@@ -70,7 +70,7 @@ fn test_parse_list() {
 }
 
 fn parse_sexp(input: &str) -> ParseResult<&str, Expr, ()> {
-    parse_list.surrounded_by(repeated(whitespace)).parse(input)
+    parse_list.surrounded_by(repeated(Whitespace)).parse(input)
 }
 
 #[test]