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