Module:Data

Documentation for this module may be created at Module:Data/doc

p = {}

p.keys = function(data)
    local keys = {}
    for k,v in pairs(data) do
        table.insert(keys, k)
    end
    return keys
end


p.sort = function(data, comparison)
    if isTable(comparison) then
        comparison = p.combineComparisons(comparison)
    end

    local keyOrder = p.keys(data)

    function cmp(key1, key2)
        return comparison(data[key1], data[key2])
    end

    table.sort(keyOrder, cmp)

    local sorted = {}
    for i,k in ipairs(keyOrder) do
        table.insert(sorted, data[k])
    end

    return sorted
end

p.filter = function(data, predicate)
    local filtered = {}
    for i,v in ipairs(data) do
        if predicate(v) then
            table.insert(filtered, v)
        end
    end
    for k,v in pairs(data) do
        if type(k) ~= 'number' and predicate(v) then
            filtered[k] = v
        end
    end
    return filtered
end


safeCompare = function(a, b)
    if type(a) ~= type(b) then
        return type(a) < type(b)
    end
    if a == nil then
        return false
    end

    -- Can't compare booleans in lua
    if a == false then
         return b
    end
    if a == true then
         return false
    end

    return a < b
end

p.asc = safeCompare

p.desc = function(a, b)
    return p.asc(b, a)
end

p.on = function(f, c)
    return function(a, b)
        return c(f(a), f(b))
    end
end

p.combineComparisons = function(comparisons)
    return function(a, b)
        for i,c in ipairs(comparisons) do
            if c(a, b) then
                return true
            end
            if c(b, a) then
                return false
            end
        end
        return false
    end
end

function isTable(t)
    return type(t) == 'table'
end

safeGet = function(data, key)
    if isTable(data) then
        return data[key]
    end
end

p.path = function(path)
    return function(data)
        local result = data
        for i,k in ipairs(path) do
            result = safeGet(result, k)
        end
        return result
    end
end
    

return p