[Pharo-project] learning rewrite rules

Stéphane Ducasse stephane.ducasse at inria.fr
Thu Nov 4 21:51:59 CET 2010


On Nov 4, 2010, at 5:51 PM, Lukas Renggli wrote:

>> ok I added the files this is better.
> 
> Yes, I could read the french article now.
> 
> I am not quite convinced with the explanation of the back-tick though:
> 
> "Un schéma peut contenir des variables en utilisant le backquote ou
> accent grave. Ainsi, `key représente n’importe quelle variable, mais
> pas une expression."
> 
> "`key" is a *meta-variable*, not necessarily a variable in the matched
> tree. Depending on the context it can also be a selector, e.g. "foo
> `key" matches all unary selectors sent to a variable called 'foo'.

I wrote that probably in 2000 so this is probably wrong.
May be my english was confused too because I took that from john's slides. 
 Indeed this is not correct, key is a meta variable that can contain an element

> Ok, my french might not be that good :-)
> 
> Also check page 42--43 of my PhD
> (http://scg.unibe.ch/archive/phd/renggli-phd.pdf): 4.1.1 Tree Pattern
> Matching. It is a bit dense and doesn't explain everything, but the
> basic matching is described and was successfully tested on students.

yes we should use that. 


what would be excellent is that we could get a nice set of examples 
that people can pick to help them. So I started to collect the answers 
so send to the list and for example the questions of doru are a good source

I know that I often forgot to handle the other statements in a match.

> 
> Lukas
> 
> -- 
> Lukas Renggli
> www.lukas-renggli.ch
> 





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