[Pharo-users] RBPattern syntax

Manuel Leuenberger leuenberger at inf.unibe.ch
Wed Feb 20 06:01:35 EST 2019


Hi Henrik,

Thanks for the the link. Interestingly, I was presented the same page on an old version, https://web.archive.org/web/20090227160738/http://st-www.cs.uiuc.edu/users/brant/Refactory/Rewrite.html <https://web.archive.org/web/20090227160738/http://st-www.cs.uiuc.edu/users/brant/Refactory/Rewrite.html>. Good to see, that there is still a maintained source.

As for the rule you presented, that is pretty cool, you got way closer to the goal than I did. John Brant mentioned that these kind of matches/transformations are not easily supported by RB by design, especially cascades seem to be problematic, as well as sequenced/nested message sends.

I am now looking into the RewriteTool (http://smalltalkhub.com/#!/~MarkRizun/RewriteTool/commits <http://smalltalkhub.com/#!/~MarkRizun/RewriteTool/commits>) and Phorms (http://smalltalkhub.com/#!/~CamilleTeruel/Patterns/commits <http://smalltalkhub.com/#!/~CamilleTeruel/Patterns/commits>), which seems to have a more powerful pattern matching language.

Cheers,
Manuel

> On 19 Feb 2019, at 14:04, Henrik Sperre Johansen <henrik.s.johansen at veloxit.no> wrote:
> 
> Manuel Leuenberger wrote
>> Hi,
>> 
>> I am looking into the RB pattern language for refactoring and I am having
>> trouble matching and replacing non-trivial pattern. Given the following
>> excerpt, I want to match "b shape 
>> <rest>
>> ." and replace it with "b shape: [ :x | x 
>> <rest>
>> ]"
>> 
>> 	b shape circle
>> 		size: 15;
>> 		color: (Color veryLightGray alpha: 0.4);
>> 		if: [ :value | toBeRed includes: value ] fillColor: Color red.
>> 
>> How can I do this? I tried using "b shape ``@messages", but this only
>> matches "b shape circle". Using "b shape `message `;middle; `;last" for
>> some reason then also matches the following, which I think it should not:
>> 
>> 	b edges
>> 		moveBehind;
>> 		connectToAll: [ :v | 
>> 			v \\ 20 ~~ 0
>> 				ifTrue: [ Array with: v + 1 with: v + 20 ]
>> 				ifFalse: [ Array with: v + 20 ] ].
>> 
>> There seems not be too much documentation about the pattern language, only
>> found tests, some short help description from RB and Yuriy's MatchTool.
>> How can I match the node correctly?
>> 
>> Cheers,
>> Manuel
> 
> The best documentation is at https://refactory.com/rewrite-tool/
> What isn't covered, is cascade nodes (`@;messages1), but my first naive
> attempt did not work as I expected on your example;
> '(b shape `@method: `@keywords) 
>   @;messages1: `@args'
> -> 
> 'b shape: [ :x |  
>   (x `@method: `@keywords) 
>      @;messages1: `@args ]'
> 
> b shape circle
>   size: 15;
>   color: (Color veryLightGray alpha: 0.4);
>   if: [ :value | toBeRed includes: value ] fillColor: Color red
> ->
> b
>   shape: [ :x | x circle size: 15 ];
>   shape: [ :x | x circle color: (Color veryLightGray alpha: 0.4) ];
>   shape: [ :x | x circle if: [ :value | toBeRed includes: value ]
> fillColor: Color red ]
> 
> 
> 
> --
> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
> 

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