Introduce 'method apply and assign' operator

I'd like to propose 'method apply and assign' operator.

purpose

We already have 'apply and assign' operators like:

*=
+=
-=
!=
:

By using those operators, we can make shorten expression:

  x.y.z = x.y.z * a

to:

  x.y.z *= a

On the other hand, we don't have the same way for method calls. This proposal introduces a shorthand way of apply and assign the result to itself for method calls in Groovy.

Proposal

Introduce new operators '=.' or '=.' like

   a  =. method(x)

or

   a .=  method(x)

means:

   a  =  a .method(x)

Example

s = "ABC"
s.= replaceAll('A', 'X')  // same as s = s.replaceAll('A', 'X')
assert s == 'XBC'

s = "ABC"
s.= padLeft(5) // same as s = s.padLeft(5)
assert s == '  ABC'

Comparison of .= and =.

'.=' is along with the other assign operators.
For example, based on this rule:

  a = a X <b>
  a X= <b>

.= is interpreted in following way:

  a = a.<xxx()>
  a .= <xxx()>

=. is based on a rule which implies under elvis operator.
For example,

   a ? a : b

is shorten by using elvis

  a ? : b

So,

  a = a.xxx()

is shorten to

  a =. xxx()

IMHO, .= is better because it is easy to remind and has similarity of other assign operators.