Looking back at it, I forgot to allow spacing between parentheses and inner expression between(lit("("), lit(")"), spaced(expr)), and using space as an oper

Looking back at it, I forgot to allow spacing between parentheses and inner expression between(lit("("), lit(")"), spaced(expr)), and using space as an operator prevents `(foo)(bar)` from being parsed as a call. This is better, just adjacent expressions with optional in-between whitespace: define_combinator(:call_op) {|left, right| group(left < ws, right) } Too late to edit, though. Oh well.