OpenEuphoria

Re: Discuss changing the behaviour of append()

• Posted by jimcbrown (admin) Jun 11, 2014
• 4137 views

I don't see the call to normal append() from deep_append(), but I also fail to see the logic bug.

That said, the existing code could be made to work with append like so:

-- This routine appends to an item at an arbitrary depth. 
-- Params: 
--     S   The sequence that holds the item which will be appended to. 
--     I   A list of indexes that point to the specific item in S to append to. 
--     X   The object that will be appended to the targeted item. 
 
function deep_append(sequence S, sequence I, object X) 
 
    if length(I) <= 1 then 
        if length(I) = 1 then 
	    if atom(S[I[1]]) then -- append() is also making this check, why do we have to make this check twice??? 
            S[I[1]] &= {X} -- having to make a new sequence also slows down the atom case 
	    else 
            S[I[1]] = append(S[I[1]], X) 
	    end if 
        end if 
        return S 
    end if 
 
    integer n = I[1] 
 
    return S[1 .. n - 1] & {deep_append(S[n], I[2 .. $], X)} & S[n + 1 .. $] 
end function 

Look how much nicer it is when append() can do atoms too!

-- This routine appends to an item at an arbitrary depth. 
-- Params: 
--     S   The sequence that holds the item which will be appended to. 
--     I   A list of indexes that point to the specific item in S to append to. 
--     X   The object that will be appended to the targeted item. 
 
function deep_append(sequence S, sequence I, object X) 
 
    if length(I) <= 1 then 
        if length(I) = 1 then 
            S[I[1]] = append(S[I[1]], X) 
        end if 
        return S 
    end if 
 
    integer n = I[1] 
 
    return S[1 .. n - 1] & {deep_append(S[n], I[2 .. $], X)} & S[n + 1 .. $] 
end function 

[/quote]

You've failed to point out a single logic bug, let alone two.

Because it doesn't exist?

I don't see append() working on atoms being a sophismata. After all, append() already works with atoms as the second parameter!

If you really believe Derek's logic bugs fall into the category of sophisma, you should at least be able to articulate the "odd consequences" or ambiguous interpretation of true/false value here.