--
-- Tests basic properties of parameters
--

local p = {}

--
-- Tests if the parameter is empty, all white space, or undefined
--

function p.is_empty(arg)
    return not arg or not arg:find('%S')
end

--
-- Returns the parameter if it has any content, the default (2nd param)
--

function p.default_to(param, default)
    if param and param:find('%S') then
        return param
    else
        return default
    end
end

--
-- Returns a list of paramaters if it has any content, or the default
--
function p.defaults(...)
    local ret = {}
    for i, v in ipairs(...) do
        if v[1] and v[1]:find('%S') then
            table.insert(ret,v[1])
        else
            -- or false, because nil is removed
            table.insert(ret,v[2] or false)
        end
    end
    return unpack(ret)
end

--
-- Tests if the parameter has content
-- The same as !is_empty, but this is more readily clear
--

function p.has_content(arg)
    return arg and arg:find('%S')
end

--
-- uppercases first letter
--

function p.ucfirst(arg)
    if not arg or arg:len() == 0 then
        return nil
    elseif arg:len() == 1 then
        return arg:upper()
    else
        return arg:sub(1,1):upper() .. arg:sub(2)
    end
end

--
-- uppercases first letter, lowercases everything else
--

function p.ucflc(arg)
    if not arg or arg:len() == 0 then
        return nil
    elseif arg:len() == 1 then
        return arg:upper()
    else
        return arg:sub(1,1):upper() .. arg:sub(2):lower()
    end
end

return p