Empty function call borks

[vihanb]

A parser error is thrown for ) when you do:

f()

or any other variation with no arguments

[taylorhansen]

I took a look at how function calls are parsed and here are the related rules:

FunctionCallList
   -> delimited[FunctionCallArgument {% id %}, _ "," _] {%
        (data, location) => new t.FunctionCall(null, data[0], location)
    %}

FunctionCallArgument
   -> %identifier _ ":" _ Expression {%
        (data, location) => new t.ArgumentCall(data[4], data[0], location)
    %}
    | Expression {%
        (data, location) => new t.ArgumentCall(data[0], null, location)
    %}

Nearley's builtin delimited macro is defined as:

delimited[el, delim] -> $el ($delim $el {% nth(1) %}):* {%
    function(d) {
        return [d[0]].concat(d[1]);
    }
%}

Which requires at least one $el.