Re: Array decomposition, more than list()

Hi Clint, On 13/05/12 18:41, Clint Priest wrote:

I've been using array decomposition in other languages such as Javascript recently and find it very useful. I did not find any conversation about it in the archives, has this topic been discussed/vetted/shot down already? Example use case: Indexed database results being iterated: Input: $tValues[$dbRow['ID1']][$dbRow['ID2']][$dbRow['ID3']] = $dbRow['Value']; Output: foreach($tValues as $ID1 => $tSubValues1) {

     foreach($tSubValues1 as $ID2 => $tSubValues2) {
         foreach($tSubValues2 as $ID3 => $Value) {
             /* Do something, such as build an SQL insert */
         }
     }

} The above is a semi-common piece of code in our production application, I could see list decomposition as a very convenient alternative. New functionality would support: foreach($tValues as $ID1 => [$ID2 => [$ID3 => $Value] ]) {

     /* Do something */

} The above also would indicate that associative array key decomposition would also be allowed. I don't believe anything like the above is possible, even outside of a foreach loop, but perhaps I am wrong there. The semantics of list() and foreach are different. A list() extracts data in variables, whereas a foreach is a loop that iterates over a structured data. Of course, I assume you know that. But what is the semantics you give to foreach($array as $key1 => [$key2 => [$key3 => $value]])? Are you interating on $key1, then $key2, then $key3, or just unfolding/extracting these variables? In other terms, what happened when $key1 has more than 1 value? Do we iterate or extract? It is not clear here.

Could you point out some references (e.g. from Javascript)? Best regards. -- Ivan Enderlin Developer of Hoa http://hoa.42/ or http://hoa-project.net/ PhD. student at DISC/Femto-ST (Vesontio) and INRIA (Cassis) http://disc.univ-fcomte.fr/ and http://www.inria.fr/ Member of HTML and WebApps Working Group of W3C http://w3.org/