Hi Tim
This is on my todo to have a serious look at the pattern matcher
Now one of the few documentation that we have in the
blog and I ported it in the blog post in /doc folder.
S
> On 4 Jun 2024, at 01:35, Tim Mackinnon <tim@testit.works> wrote:
>
> Hey Gabriel - thanks for chipping in - you've made me realise that its
> perhaps easier to give a simpler example (for the multiple replacement)., and
> while trying to explain in simpler terms I managed to solve the problem
> myself - but it does demonstrate the docs around this need a bit more work as
> I didn't find it easy to reason on.
>
> I am still confused what the setting "this rule is for a method" does - so
> am keen for someone to shed light.
>
> Anyway for my example it seems that I have to be very specific in how I match
> things for example I had to use the search pattern:
>
> taskbarButtonMenu: `arg
> | `@temps |
> `.@before.
>
> moveSubmenu
> addToggle: 'Move right' translated
> target: self
> selector: #taskbarMoveRight
> getStateSelector: nil
> enablementSelector: #canBeMovedToRight.
>
> `.@after
>
> And it took me ages to realise that I have to specify the temp vars matching,
> and also understand that the @before and @after both needed the "." to
> represent lists of expressions both before and after and then the really
> subtle "." after @before which I guess prevents greedy matching.
>
> With all of that in place, could then have the write rule add an extra
> statement after the moveSubmenu (or as many as I want)
>
> e.g.
>
> taskbarButtonMenu: `arg
> | `@temps |
> `.@before.
>
> moveSubmenu
> addToggle: 'Move right' translated
> target: self
> selector: #taskbarMoveRight
> getStateSelector: nil
> enablementSelector: #canBeMovedToRight.
>
> moveSubmenu
> addToggle: 'Move to...' translated
> target: self
> selector: #taskbarMoveTo
> getStateSelector: nil.
>
> `.@after
>
>
> I'm curious now whether there is a more efficient way to do what I have done?
> Possibly the {} syntax could help now i've figured out the basic matching.
>
> I really find it easy to confuse that if you don't specify the @temps section
> that can leave out a lot of matches (it essentialy means 0 or more temps vs.
> leaving it out means no temps at all). This is a trap that the docs should
> call out better I think.
>
> Anyway - now I just need to figure out how to do this programatically - and
> possibly I can write a few more useful refactorings I've also thought it was
> odd that were missing.
>
> On Mon, 3 Jun 2024, at 12:19 PM, Gabriel Cotelli wrote:
>> I've used the rewrite tool extensively but never tried to create more than
>> one expression from the original one. I think that this probably won't work
>> because in your example the code is just statements, but the matching
>> expression can be in code like this:
>>
>> self doSomething: (
>> moveSubmenu
>> addToggle: 'Move right' translated
>> target: self
>> selector: #taskbarMoveRight
>> getStateSelector: nil
>> enablementSelector: #canBeMovedToRight)
>>
>> and in this case, you cannot replace this with two statements. So I'm
>> tempted to say that what you want is not supported.
>>
>> Regards, Gabriel
>>
>> On Mon, Jun 3, 2024 at 5:44 AM Tim Mackinnon <tim@testit.works> wrote:
>>
>> I've never really learned the rewrite tool but while waiting for changes to
>> propagate through P12, I thought maybe I could use it to safely patch
>> changes until there are official updates (and it was a good chance to get
>> more familiar with it).
>>
>> I thought there was more documentation available for how it works
>> (interested in any old articles - but the online help in P12 is ok -
>> although it doesn't display in markdown - in fact give there is markdown
>> support now - I am a bit confused what should appear more readable these
>> days - and how to fix/contribute changes to help).
>>
>> This aside - I wanted to patch the SystemWindow>>taskbarButtonMenu: (and add
>> my fix to move tabs to any position).
>>
>> I started writing the following search expression - the find the last call
>> to #addToggle:... method call that has a literal referencing
>> #canBeMovedRight - as I want to add my new menu item after it.
>>
>> e.g.
>>
>> moveSubmenu `@addToggle: `{ :node | node isLiteralNode and: [ node value =
>> #canBeMovedToRight] }
>>
>> but I'm not sure my {} filter block is ever called, as the above matches
>> both addToggle:... calls, and not the one I'm after? I don't understand this
>> - any have ideas on the proper syntax for generic matching?
>>
>> Anyway - I decided that in my case there is only one - so I can match it
>> explicitly and so I search on the full call:
>>
>> and I entered this:
>> moveSubmenu
>> addToggle: 'Move right' translated
>> target: self
>> selector: #taskbarMoveRight
>> getStateSelector: nil
>> enablementSelector: #canBeMovedToRight.
>>
>> Which matches exactly - then I want to replace the single statement with 2
>> statements e.g.
>>
>> moveSubmenu
>> addToggle: 'Move right' translated
>> target: self
>> selector: #taskbarMoveRight
>> getStateSelector: nil
>> enablementSelector: #canBeMovedToRight.
>>
>> moveSubmenu
>> addToggle: 'Move to' translated
>> target: self
>> selector: #taskbarMoveTo
>> getStateSelector: nil.
>>
>>
>> However this gives an error in the rewrite tool (actually it results in a
>> zero change, that then gives an error for EpMonitor).
>>
>> But my question is - why can't you rewrite a single statement to multiple
>> ones? I have noticed that in this case I can cascade the message send - and
>> this then rewrites properly - so it looks like it wants to replace a single
>> node with a single node.
>>
>> If I couldn't cascade - It seems I would have to rewrite with something
>> like: [ "put multiple expressions here" ] value.
>>
>> This seems an odd choice - but am I missing something obvious?
>>
>> Do you have to do what I'm proposing in 2 steps - rewrite to a block (or
>> some equivalent) and then a 2nd rewrite to simplify the expression (like a
>> refactor step) - so its more provably correct?
>>
>> I'm just curious on this - as it seemed time to learn this properly?
>>
>> Tim
Stéphane Ducasse
http://stephane.ducasse.free.fr
06 30 93 66 73
"If you knew today was your last day on earth, what would you do differently?
....ESPECIALLY if, by doing something different, today might not be your last
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