Go back to having `atom` be the unit of argument lists and such.
Go back to having `atom` be the unit of argument lists and such.

Having it be a unary expression would have caused some odd ambiguities,
e.g. is `foo - 1` an infix expression (subtract `1` from `foo`) or a
function call (give `foo` the value `-1` as an argument)?

danfuzz/samizdat,danfuzz/samizdat,danfuzz/samizdat,danfuzz/samizdat