external_functions.lua

--------------------------------------------------------------------------
--[[

http://lua-users.org/wiki/SortedIteration

Ordered table iterator, allow to iterate on the natural order of the keys of a
table.

Example:

t = {
    ['1'] = nil,
    ['2'] = nil,
    ['3'] = 'xxx',
    ['4'] = 'xxx',
    ['5'] = 'xxx',
}

print("Ordered iterating")
for key, val in orderedPairs(t) do
    print(key.." : "..val)
end

Output:
Ordered iterating
3: xxx
4: xxx
5: xxx
]]

function cmp_multitype(op1, op2)
    local type1, type2 = type(op1), type(op2)
    if type1 ~= type2 then --cmp by type
        return type1 < type2
    elseif type1 == "number" and type2 == "number"
        or type1 == "string" and type2 == "string" then
        return op1 < op2 --comp by default
    elseif type1 == "boolean" and type2 == "boolean" then
        return op1 == true
    else
        return tostring(op1) < tostring(op2) --cmp by address
    end
end

function __genOrderedIndex( t )
    local orderedIndex = {}
    for key in pairs(t) do
        table.insert( orderedIndex, key )
    end
    table.sort( orderedIndex, cmp_multitype ) --### CANGE ###

    return orderedIndex
end

function orderedNext(t, state)
    -- Equivalent of the next function, but returns the keys in the alphabetic
    -- order. We use a temporary ordered key table that is stored in the
    -- table being iterated.

    --print("orderedNext: state = "..tostring(state) )
    if state == nil then
        -- the first time, generate the index
        t.__orderedIndex = __genOrderedIndex( t )
        key = t.__orderedIndex[1]

        if key ~= "__orderedIndex" then
           return key, t[key]
        end
    end
    -- fetch the next value
    key = nil
    for i = 1,table.getn(t.__orderedIndex) do
        if t.__orderedIndex[i] == state then
            key = t.__orderedIndex[i+1]
        end
    end

    if key and key ~= "__orderedIndex "then
        return key, t[key]
    end

    -- no more value to return, cleanup
    t.__orderedIndex = nil
    return
end

function orderedPairs(t)
   -- Equivalent of the pairs() function on tables. Allows to iterate
   -- in order
   return orderedNext, t, nil
end