Maximum CD 2010 July/maximum-cd-2010-07.iso/DiscContents/wesnoth-1.8-win32.exe/data/lua/helper.lua

Text File | 2010-03-25 | 7.5 KB | 275 lines

--! #textdomain wesnoth

local helper = {}

--! Interrupts the current execution and displays a chat message that looks like a WML error.
function helper.wml_error(m)
    error("~wml:" .. m, 0)
end

--! Returns an iterator over teams that can be used in a for-in loop.
function helper.all_teams()
    local function f(s)
        local i = s.i
        local team = wesnoth.get_side(i)
        s.i = i + 1
        return team
    end
    return f, { i = 1 }
end

--! Returns the first subtag of @a cfg with the given @a name.
--! If @a id is not nil, the "id" attribute of the subtag has to match too.
--! The function also returns the index of the subtag in the array.
function helper.get_child(cfg, name, id)
    -- ipairs cannot be used on a vconfig object
    for i = 1, #cfg do
        local v = cfg[i]
        if v[1] == name then
            local w = v[2]
            if not id or w.id == id then return w, i end
        end
    end
end

--! Returns an iterator over all the subtags of @a cfg with the given @a name.
function helper.child_range(cfg, tag)
    local function f(s)
        local c
        repeat
            local i = s.i
            c = cfg[i]
            if not c then return end
            s.i = i + 1
        until c[1] == tag
        return c[2]
    end
    return f, { i = 1 }
end

--! Modifies all the units satisfying the given @a filter.
--! @param vars key/value pairs that need changing.
--! @note Usable only during WML actions.
function helper.modify_unit(filter, vars)
    wesnoth.fire("store_unit", {
        [1] = { "filter", filter },
        variable = "LUA_modify_unit",
        kill = true
    })
    for i = 0, wesnoth.get_variable("LUA_modify_unit.length") - 1 do
        local u = "LUA_modify_unit[" .. i .. "]"
        for k, v in pairs(vars) do
            wesnoth.set_variable(u .. '.' .. k, v)
        end
        wesnoth.fire("unstore_unit", {
            variable = u,
            find_vacant = false
        })
    end
    wesnoth.set_variable("LUA_modify_unit")
end

--! Fakes the move of a unit satisfying the given @a filter to position @a x, @a y.
--! @note Usable only during WML actions.
function helper.move_unit_fake(filter, to_x, to_y)
    wesnoth.fire("store_unit", {
        [1] = { "filter", filter },
        variable = "LUA_move_unit",
        kill = false
    })
    local from_x = wesnoth.get_variable("LUA_move_unit.x")
    local from_y = wesnoth.get_variable("LUA_move_unit.y")

    wesnoth.fire("scroll_to", { x=from_x, y=from_y })

    if to_x < from_x then
        wesnoth.set_variable("LUA_move_unit.facing", "sw")
    elseif to_x > from_x then
        wesnoth.set_variable("LUA_move_unit.facing", "se")
    end
    wesnoth.set_variable("LUA_move_unit.x", to_x)
    wesnoth.set_variable("LUA_move_unit.y", to_y)

    wesnoth.fire("kill", {
        x = from_x,
        y = from_y,
        animate = false,
        fire_event = false
    })

    wesnoth.fire("move_unit_fake", {
        type      = "$LUA_move_unit.type",
        gender    = "$LUA_move_unit.gender",
        variation = "$LUA_move_unit.variation",
        side      = "$LUA_move_unit.side",
        x         = from_x .. ',' .. to_x,
        y         = from_y .. ',' .. to_y
    })

    wesnoth.fire("unstore_unit", { variable="LUA_move_unit", find_vacant=true })
    wesnoth.fire("redraw")
    wesnoth.set_variable("LUA_move_unit")
end

local variable_mt = {}

local function get_variable_proxy(k)
    local v = wesnoth.get_variable(k, true)
    if type(v) == "table" then
        v = setmetatable({ __varname = k }, variable_mt)
    end
    return v
end

local function set_variable_proxy(k, v)
    if getmetatable(v) == variable_mt then
        v = wesnoth.get_variable(v.__varname)
    end
    wesnoth.set_variable(k, v)
end

function variable_mt.__index(t, k)
    local i = tonumber(k)
    if i then
        k = t.__varname .. '[' .. i .. ']'
    else
        k = t.__varname .. '.' .. k
    end
    return get_variable_proxy(k)
end

function variable_mt.__newindex(t, k, v)
    local i = tonumber(k)
    if i then
        k = t.__varname .. '[' .. i .. ']'
    else
        k = t.__varname .. '.' .. k
    end
    set_variable_proxy(k, v)
end

local root_variable_mt = {
    __index    = function(t, k)    return get_variable_proxy(k)    end,
    __newindex = function(t, k, v)
        if type(v) == "function" then
            -- User-friendliness when _G is overloaded early.
            -- FIXME: It should be disabled outside the "preload" event.
            rawset(t, k, v)
        else
            set_variable_proxy(k, v)
        end
    end
}

--! Sets the metable of @a t so that it can be used to access WML variables.
--! @return @a t.
--! @code
--! helper.set_wml_var_metatable(_G)
--! my_persistent_variable = 42
--! @endcode
function helper.set_wml_var_metatable(t)
    return setmetatable(t, root_variable_mt)
end

local fire_action_mt = {
    __index = function(t, n)
        return function(cfg) wesnoth.fire(n, cfg) end
    end
}

--! Sets the metable of @a t so that it can be used to fire WML actions.
--! @return @a t.
--! @code
--! W = helper.set_wml_action_metatable {}
--! W.message { speaker = "narrator", message = "?" }
--! @endcode
function helper.set_wml_action_metatable(t)
    return setmetatable(t, fire_action_mt)
end

local create_tag_mt = {
    __index = function(t, n)
        return function(cfg) return { n, cfg } end
    end
}

--! Sets the metable of @a t so that it can be used to create subtags with less brackets.
--! @return @a t.
--! @code
--! T = helper.set_wml_tag_metatable {}
--! W.event { name = "new turn", T.message { speaker = "narrator", message = "?" } }
--! @endcode
function helper.set_wml_tag_metatable(t)
    return setmetatable(t, create_tag_mt)
end

--! Fetches all the WML container variables with name @a var.
--! @returns a table containing all the variables (starting at index 1).
function helper.get_variable_array(var)
    local result = {}
    for i = 1, wesnoth.get_variable(var .. ".length") do
        result[i] = wesnoth.get_variable(string.format("%s[%d]", var, i - 1))
    end
    return result
end

--! Puts all the elements of table @a t inside a WML container with name @a var.
function helper.set_variable_array(var, t)
    wesnoth.set_variable(var)
    for i, v in ipairs(t) do
        wesnoth.set_variable(string.format("%s[%d]", var, i - 1), v)
    end
end

--! Creates proxies for all the WML container variables with name @a var.
--! This is similar to helper.get_variable_array, except that the elements
--! can be used for writing too.
--! @returns a table containing all the variable proxies (starting at index 1).
function helper.get_variable_proxy_array(var)
    local result = {}
    for i = 1, wesnoth.get_variable(var .. ".length") do
        result[i] = get_variable_proxy(string.format("%s[%d]", var, i - 1))
    end
    return result
end

--! Displays a WML message box with attributes from table @attr and options
--! from table @options.
--! @return the index of the selected option.
--! @code
--! local result = helper.get_user_choice({ speaker = "narrator" },
--!     { "Choice 1", "Choice 2" })
--! @endcode
function helper.get_user_choice(attr, options)
    local result = 0
    function wesnoth.__user_choice_helper(i)
        result = i
    end
    local msg = {}
    for k,v in pairs(attr) do
        msg[k] = attr[k]
    end
    for k,v in ipairs(options) do
        table.insert(msg, { "option", { message = v,
            { "command", { { "lua", {
                code = string.format("wesnoth.__user_choice_helper(%d)", k)
            }}}}}})
    end
    wesnoth.fire("message", msg)
    wesnoth.__user_choice_helper = nil
    return result
end

--! Returns the distance between two tiles given by their WML coordinates.
function helper.distance_between(x1, y1, x2, y2)
    local function is_even(v) return v % 2 == 0 end
    local hdist = math.abs(x1 - x2)
    local vdist = math.abs(y1 - y2)
    if (y1 < y2 and not is_even(x1) and is_even(x2)) or
       (y2 < y1 and not is_even(x2) and is_even(x1))
    then vdist = vdist + 1 end
    return math.max(hdist, vdist + math.floor(hdist / 2))
end

return helper