Re: [jamboost] container.jam question

From: Rene Rivera (grafik666_at_[hidden])
Date: 2002-07-02 12:11:58

[2002-07-02] Rene Rivera wrote:

>[2002-07-02] Vladimir Prus wrote:
>
>>Rene Rivera wrote:
>>> [2002-07-02] Vladimir Prus wrote:
>>> >Rene Rivera wrote:
>>> >> Getting at subelements is bit tricky, but jam doesn't have an easy
way
>>> :
>>> :-(
>>> :
>>> >> l0 = [ $(l).at 0 ] ;
>>> >> ECHO [ $(l0).at 0 ] ; # >> 1
>>> >
>>> >Can we make this work without second level lists?
>>> >
>>> > l0 = [ $(l).at 0 ] ;
>>> > ECHO $(l0[1]) ;
>>> >
>>> >I'm quite happy with jam lists, and most rules now take jam lists.
>Second
>>> >level list is a little bit overkill for my task.
>>>
>>> The closest you can get to that is:
>>>
>>> $(l0) = $($(l).self.value[1]) ;
>>> ECHO $($(l0).self.value[1]) ;
>>>
>>> I think that will work. Maybe Dave has some better syntax up his sleeve
>>> when it comes to class'es ;-)
>>
>>I'm thinking that we probably can wrap values in some class when putting
it 
>>to container and unwrapping it when extracting.... ?
>
>Hmmm... How about extending the "at" accessor to allow the dereferencing
>directly like so:
>
>ECHO [ $(l).at 0 : 1 ] ; # >> 2
>
>That seems as simple a syntax, also looks like multi-dimensional arrays :-)

One other thought if that doesn't seem apporpriate for what you need... to
do the unwrapping I'd add another accessor like this:

l0 = [ $(l).get-at 0 ] ;
ECHO $(l0[1]) ;

A better name than "get-at" would be good though.

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