print certain atoms in single quotes.
@@ -552,7 +552,11 @@ impl fmt::Display for Constant {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
&Constant::Atom(ref atom) =>
- write!(f, "{}", atom),
+ if atom.as_str().chars().any(|c| ".$'\" ".contains(c)) {
+ write!(f, "'{}'", atom.as_str())
+ } else {
+ write!(f, "{}", atom.as_str())
+ },
&Constant::Char(c) =>
write!(f, "'{}'", c as u8),
&Constant::EmptyList =>
