Gathering statistics on messages sent to an object

> Hi Alistair.
>
> Do you know that you are able to count any message send? (not only external).
> For this you need prevent meta recursion. Now inside message processing you do:
>
>     aMessage sendTo: anObject
>
> which produces another intercepting message #perform:withArguments which
> repeats original message send.
> Fortunately Ghost handles such kind of meta recursion and there is no infinite
> loop here: any self-sends are ignored in such cases.
>
> If you want intercept any message try following code:
>
>     ExternalSendTrace>>send: aMessage to: anObject
>     | method |
>     announcer announce: (ExternalSendAnnouncement message: aMessage trace:
>     self).
>     method := anObject class lookupSelector: aMessage selector.
>     ^GHMetaMessages executeWith: anObject andArguments: aMessage arguments
>     method: method
>
>
> In that case we lookup and execute method by using mirror primitive which not
> sends any message to object.
>
> For example:
>
>
>     rect := 10@30 corner: 100@300.
>     trace := ExternalSendStats logStatsFor: rect.
>     rect area.
>     trace stats.
>      "a Dictionary(#area->1 #height->1 #width->1 )"
>
>
>
> Best regards,
> Denis

> 2017-04-24 14:43 GMT+02:00 Alistair Grant <[hidden email]>:
>
>     If you subscribe to pharo-dev you will have seen that I've been looking
>     at the primitives used in DiskStore.
>
>     As part of that investigation I wanted to get an idea of which messages
>     are typically sent to DiskStore and how often.
>
>     Denis Kudriashov provided a neat package that implements a "halt on
>     next object call".  I've been wanting to play with the package for a
>     while and decided this was a good opportunity.
>
>     I've extended that package to keep count of how many times messages are
>     sent to a target object, e.g.:
>
>
>
>     | point trace |
>
>     point := 2@3.
>     trace := ExternalSendStats logStatsFor: point.
>     point
>             x;
>             y;
>             angle;
>             x.
>     trace stats.
>     "a Dictionary(
>             #angle->1
>             #x->2
>             #y->1 )"
>
>
>
>     The package is probably too simplistic, and there's bound to be other
>     ways to do this, but it met my immediate needs and gave me a chance to
>     try out the Ghost package.  I'll extend it if and when I need to.
>
>     Many thanks to Denis for making the Ghost package available, and
>     hopefully this is useful for someone, or at least triggers some new
>     ideas.
>
>     Denis' original article is at: http://dionisiydk.blogspot.cz/2016/04/
>     halt-next-object-call.html
>
>     The extensions can be installed with:
>
>     Metacello new
>             baseline: 'AkgGhost';
>             repository: 'github://akgrant43/akg-ghost:master/mc';
>             load