Arrays of arrays or comparable enhancement

[GoogleCodeExporter]

Gawk has arrays of arrays which I find hard (impossible?) to do without in some 
applications (without sacrificing efficiency). 
It is easy enough to add my own functions to replace gawk's sorting functions,
but arrays of arrays, not so easy.
All I really need is the ability to do something like
for( (const , i) in a) ...
where I can specify const and mawk will iterate over i.  
Mawk rocks!

Original issue reported on code.google.com by wbr...@gmail.com on 29 Apr 2015 at 3:44