It looks like this for-statement is working recursively down a array-of-arrays-of-arrays-... type thing.. Thus there is no way to turn it into a 'traditional' 0->N for-loop.

I could turn it into a while statement for you, maybe that helps:

my $L = $tabs->[10];
while ($L)                         # ie, as long as $L has a value
{
   $m->[ $L->[1] ] = $L->[2];      # assign the 3rd value referenced b
+y $L to the arrayref $m 
                                   # (indexing with the 2nd value refe
+renced by $L)
   $L = $L->[0];                   # assign $L the first value of the 
+arrayref its referencing 
                                   # (or undef if not available)
}
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No idea how C# would do this though..

C.