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Can local variables assignments be considered pure functional without monads?Okay, this might seem like an odd question, but is there contention on whether or not a while loop that performs assignment on local function variables is pure functional? For example the following Java code: int process(int[] xs) { int zeros = 0; int sum = 0; int i=0; while (i < xs.Size) { if (xs[i] == 0) zeros++; sum += xs[i]; ++i; } return sum - zeros; } Now I have heard frequently that the above code is considered to have side-effects because of the local assignments to variables. However, the mapping to pure-functional stack-based code (here shown in Cat) is very straightforward: define process { // top argument = xs 0 // zeros 0 // sum 0 // i [ dig3 // bring xs to top of local stack dupd swap get_at eqz // xs[i] == 0 [[inc] dip3] // inc zeros [] if dupd swap get_at // tmp = xs[i] [bury3] dip // put xs to bottom of local stack swap [add_int] dip // sum += tmp inc // ++i ] [ dig3 count [bury3] dip // tmp = xs.Size dupd lt_int // i < tmp ] while pop // remove i swap sub_int // sum-zeros } So, my problem is that I am not sure whether this is old news or new news. Any feedback would be appreciated. By cdiggins at 2008-04-10 17:30 | LtU Forum | previous forum topic | next forum topic | other blogs | 11562 reads
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