571475 - Use of rest arguments, arguments object, and apply in builtin should be avoided

Status: RESOLVED WONTFIX

(Tamarin Graveyard :: Library, defect, P3)

Description

[Lars T Hansen]

Now that we have rest arg optimization (see bug #569321) it is possible to avoid allocating the rest arguments array or the arguments object, and code should avoid capturing that object just to pass it to apply.  Instead, it is possible to create internal subroutines that take an appropriate maximum number of arguments, and then structure the front end function like this:

 function f(...rest) {
    switch (rest.length) {
        case 0: return _f(0, undefined, undefined, undefined);
        case 1: return _f(1, rest[0], undefined, undefined);
        ...
    }
  }

where _f is some internal function.  Sometimes the argument count can be omitted in favor of passing a cookie for unsupplied arguments.

There are many uses of 'apply' in the builtins and most are there because of the cliche that captures the rest argument and passes the arguments on.

Comment 1

[Sylvestre Ledru [:Sylvestre]]

Tamarin is a dead project now. Mass WONTFIX.

Comment 2

[Sylvestre Ledru [:Sylvestre]]

Tamarin isn't maintained anymore. WONTFIX remaining bugs.