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[mkgmap-dev] Patch: New filter "not-contained"

From GerdP gpetermann_muenchen at hotmail.com on Thu Jan 29 20:31:11 GMT 2015 

Hi Maxim,

I tried to find out if the patch has a side effect, but
I failed. From your description I understand that
I should be able to produce different results (not
using the new filter, just something that workded before)

Can you give an example where I should find a difference?

Gerd


"Maxim Düster" wrote
> Hi, Gerd, 
> 
>   
> 
> I think, there shouldn't be a problem. Actually, if you are using a
> filter inside of the apply{} block, you would presumably like to be able
> to access the current element from the filter. At the moment you don't
> have such a possibility at all. 
> 
> If though there will be need to pass a tag from the global relation to the
> filter, one can always assign a global tag to a temporary local tag before
> calling the filter with this local tag. 
> 
> So, in my mind, nothing should go wrong here. Perhaps someone else can say
> something more regarding this issue. 
> 
>   
> 
> Max 
> 
>  
> 
> Gesendet: Donnerstag, 29. Januar 2015 um 18:30 Uhr 
> Von: GerdP <

> gpetermann_muenchen@

> > 
> An: 

> mkgmap-dev at .org

>  
> Betreff: Re: [mkgmap-dev] Patch: New filter "not-contained" 
> 
> Hi Max, 
> 
> not sure. What will happen if one uses another filter in the relations
> file? 
> 
> Gerd 
> 
> 
> "Maxim Düster" wrote 
> > Hi, Gerd, 
> > 
> >   
> > 
> > the change is caused by the fact that the filter was thought
> primarily for 
> > working in relations file inside of the apply{} block and needs that
> the 
> > tag given as last parameter is a local tag of the element being
> processed 
> > (e.g. a way). But the old code line says: "value = 
> > filter.filter(tagval,el);", 'el' being the
> parent relation 
> > the way is in. That is, in the filter I only have an access to the 
> > (global) relation's tags, but what I actually need are the
> tags of the 
> > (local) element being currently processed. 
> > 
> > While applying filters to "plain" elements (those
> not inside a 
> > relation, e.g. in points or lines files), 'local_el'
> and 
> > 'el' are equal, so my change should not corrupt
> anything. 
> > 
> >   
> > 
> > Max 
> > 
> >   
> > 
> > Gesendet: Donnerstag, 29. Januar 2015 um 11:20 Uhr 
> > Von: "Gerd Petermann" < 
> 
> > gpetermann_muenchen@ 
> 
> > > 
> > An: " 
> 
> > mkgmap-dev at .org 
> 
> > " < 
> 
> > mkgmap-dev at .org 
> 
> > > 
> > Betreff: Re: [mkgmap-dev] Patch: New filter
> "not-contained" 
> > 
> > 
> > 
> > Hi Maxim, 
> > 
> > please can you explain the reason for the change in ValueItem? 
> > 
> > Gerd 
> >   
> > 
> > From: 
> 
> > maxc@ 
> 
> > 
> > To: 
> 
> > mkgmap-dev at .org 
> 
> > 
> > Date: Wed, 28 Jan 2015 12:12:25 +0100 
> > Subject: [mkgmap-dev] Patch: New filter
> "not-contained" 
> >   
> > 
> > Hello! 
> >   
> > I've attached a patch with a new filter that helps while
> processing, 
> > for example, public transport relations. The reason: there can be
> multiple 
> > route relations with the same ref attribute (for example, one for the 
> > forward direction, one for the return direction), combined to a 
> > route_master relation. 
> > 
> > If you want a name for a way to contain the refs of all of the routes 
> > going through that way, you have a problem that some refs will be
> present 
> > more than once, similar to "1,1,2,2,2" (if we
> assume that route 
> > 1 has two instances, and route 2 - three instances). 
> > 
> > The new filter helps to circumvent this. It takes 2 parameters: a 
> > delimiter (a comma in the example above) and the name of a tag
> containg 
> > the list. The filter works a bit like the
> "not-equal" filter, 
> > but it doesn't just compare two values; instead it looks if
> the 
> > tag's value (to which the filter is being applied) is
> contained in the 
> > list from the (other) given tag. If it is not the case, the value can
> be 
> > added to the list, otherwise the tag is considered unset. 
> > 
> >   
> > 
> > Simple example for relations file: 
> > 
> >   
> > 
> > type=route & route=bus & ref=* { 
> >    apply { 
> >       set 
> >
> route_ref='$(route_ref),${ref|not-contained:,:route_ref}' 
> > | '$(route_ref)' |
> '${ref}'; 
> >    } 
> > } 
> > 
> >   
> > 
> > Here, ref value is only added to route_ref if it is not already
> contained 
> > in that list (with separator ','). Otherwise, the
> value of 
> > route_ref is unchanged. 
> >   
> > Cheers! 
> > Max 
> > 
> > 
> > _______________________________________________ mkgmap-dev mailing
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> 
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> 
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> > 
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> > 
> > 
> > 
> > 
> > 
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