Assuming a single-keyword is a mutator?  Object>>#at: is not a
mutator.  #indexOf: is not.  #first: is not.  Obviously many more..

If API balance is the goal of this, perhaps #asMutator should be
removed instead.   This feels application-specific...

On Wed, Mar 20, 2019 at 2:05 PM <commits at source.squeak.org> wrote:
>
> Patrick Rein uploaded a new version of Collections to project The Trunk:
> http://source.squeak.org/trunk/Collections-pre.822.mcz
>
> ==================== Summary ====================
>
> Name: Collections-pre.822
> Author: pre
> Time: 20 March 2019, 8:05:20.383677 pm
> UUID: 483c4461-cee4-4a4f-82d3-fbc03e7201cc
> Ancestors: Collections-dtl.821
>
> Adds #isMutator to Symbol which is analogous to asMutator.
>
> =============== Diff against Collections-dtl.821 ===============
>
> Item was added:
> + ----- Method: Symbol>>isMutator (in category 'testing') -----
> + isMutator
> +
> +       ^ self isKeyword and: [self numArgs = 1]!
>
>