Re: [boost] Interest for a perl6-like-junctions-class?

From: Florian Stegner (FlSt_at_[hidden])
Date: 2005-08-10 08:10:12

Rob Stewart wrote:
> From: Matthew Vogt <mattvogt_at_[hidden]>
> 
>>Matthew Vogt wrote:
>>
>>
>>>How about 'subrange_of'?
>>
>>Actually, scratch that; it doesn't sound right.  It *is* a subset you're 
>>finding, albeit with extra constraints.  Maybe 'bounded_subset_of'?
>>
>>I like the 'between' formulation in your other post.
> 
> 
> I've uploaded yet another revision of multivalues.zip.  I decided
> to go with "some" for n_m/subrange/subset/i_j/a_z/x_y/etc

I aggree with it.  But each_of is still confusing for me. You 
implemented it as the negation of all_of: "( all_of( a ) > x ) !=   ( 
each_of( x ) > x )" is true for all a and x. each_of in your 
implementation is equivalent to not_all_of in mine. not_all_of in your 
implementation is the negation of one_of, what is ok. But each_of( a ) 
== x  means that none or more but not all elements of a are equal to x. 
There must be a better name as each_of. I had just a quick look on your 
new implementation. I will post my results later.

> This one runs 2016 tests and compiles in just over nine minutes
> on my system (still GCC 3.2.3).
Could you send me the testfiles .cpp or upload them to the sandbox file 
vault? Then I could help you to complete them. What is about the tests 
for the relations between the multivalues I sent you?

> There are still some things missing:
> 
>  - tests for some_of, between, and exactly.

I found also relations between expressions with one_of.

>  - support for user-defined predicates that only know how to
>    compare to values and not multivalues

My implementation (v11) can compare two multivalues (junctions) with 
user defined predicates. I wrote swap_operands as a function object 
wrapper, if the rhs-parameter is a multivalue. There is still the 
problem with lambda-expressions. The only working idea I found to allow 
the usage of lambda expressions would be to have a function like this:

compare( all_of( a ), _1 < _2, any_of( b ) )

But what is about the []-operator?

all_of( a ) [ _2 > _1 ] any_of( b )

Then we would have no more problems with operator precendence. :-)

>  - documentation

I will help you so good I can.

> If there is reasonable consensus for what we have thus far, among
> those interested in this library, I think we should start to work
> on some documentation so more people will take a look at the
> library.

There is a boost-sandbox CVS. Now after we have a common version ( Now 
it makes no sense develop my prototype further ) this would be a good 
place for our library. Or is the stage to early?

Sincerely
   Florian