Elvish_Hunter's Lua thread

[Elvish_Hunter]

Yesterday I finished writing my second Lua tag. I took inspiration from the FutureWML page, and so we have an [harm_unit] tag.

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local helper = wesnoth.require "lua/helper.lua"

function wesnoth.wml_actions.harm_unit(cfg)
	local amount = tonumber(cfg.amount) or helper.wml_error("[harm_unit] missing required amount= attribute")
	local damage_type = (cfg.damage_type)
	local damage
	for index, unit_to_harm in ipairs(wesnoth.get_units(cfg)) do
		if damage_type then
			damage = (amount / 100) * wesnoth.unit_resistance(unit_to_harm, tostring(damage_type))
			else
				damage = amount
		end
		damage = math.floor(damage)
		unit_to_harm.hitpoints = unit_to_harm.hitpoints - damage
		wesnoth.float_label(unit_to_harm.x,unit_to_harm.y,string.format("<span foreground='red'>%d</span>",damage))
		if unit_to_harm.hitpoints <= 0 then
			wesnoth.fire("kill", {id=unit_to_harm.id, animate="yes", fire_event="yes"})	
		end
		wesnoth.set_variable("harm_amount", damage)
	end
	wesnoth.wml_actions.redraw {}
end

How it works:
This tag should harm selected units in a similar way to what happens in combat, and if their HP goes to 0 or less, kill them.
It requires the following:
- StandardUnitFilter, to select the units to harm
- amount, the amount of damage to apply on units; if missing, this gives an error
- damage_type, if present the final damage will be altered by unit resistance
It also sets the damage applied to variable harm_amount.

Now, I have three questions:
- FutureWML says that it should have also a "alignment" key. There is any way to implement this, that should be getting a particular location's ToD and check it against cfg.alignment? Please keep in mind that I'm still a Lua beginner.
- I placed ipairs(wesnoth.get_units) directly in the cycle for. Should I have used this instead?

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local units_to_harm=wesnoth.get_units(cfg)
for index, unit_to_harm in ipairs(units_to_harm) do

- If a leader is killed by wesnoth.fire{"kill"}, if no last breath/death event for this unit is defined, or if such event doesn't contain [endlevel] result=defeat, defeat isn't immediate, but happens on the next turn start. Is it an error of mine that I didn't noticed? If yes, how to fix this?

I already tested it, and seems to work. Can you kindly tell me if there is something else to correct, or is it ready for core?

[Anonymissimus]

Maybe you should post the stuff as patches then (if you want to get write access like me )
http://gna.org/patch/?group=wesnoth

2 problems:
-The fired events can invalidate unit references which are still to be iterated on (kill one of the remaining units) - look how it's done in move_unit (it's the same problem there).
-harm_amount is never cleared. Don't think there's a functionality for this yet... it should be auto-cleared when leaving the calling event.

There is any way to implement this, that should be getting a particular location's ToD and check it against cfg.alignment?

If you've found no suitable wesnoth.something function then there's no way yet apparently...

- I placed ipairs(wesnoth.get_units) directly in the cycle for. Should I have used this instead?

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local units_to_harm=wesnoth.get_units(cfg)
for index, unit_to_harm in ipairs(units_to_harm) do

If you need units_to_harm later on make a variable, else call it directly.

- If a leader is killed by wesnoth.fire{"kill"}, if no last breath/death event for this unit is defined, or if such event doesn't contain [endlevel] result=defeat, defeat isn't immediate, but happens on the next turn start. Is it an error of mine that I didn't noticed? If yes, how to fix this?

I has always been this way afaik. (idependently from your lua code here)

[Elvish_Hunter]

Maybe you should post the stuff as patches then (if you want to get write access like me )

I'd be honoured to gain a Code and WML Contributor title, of course, but I don't know how to make patches on Windows...
EDIT: this mean that I'll have to install SVN, right?

-The fired events can invalidate unit references which are still to be iterated on (kill one of the remaining units) - look how it's done in move_unit (it's the same problem there).

I'll look. Anyway, when I tested, this code really killed only those units that needed to be killed, that is those with 0 or less HP.
EDIT: Looked, apparently it's done in the same way:

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if fire_event then
				wesnoth.fire_event("moveto", x, y, x2, y2)
			end

-harm_amount is never cleared.

harm_amount is not supposed to be cleared, but instead stored as WML variable. Not a bug, a feature.

Ideas that are fairly sound
New Actions
* [harm_unit] - harms a unit(s) then saves the amount as $harm_amount
o [filter]
o amount
o damage_type
o alignment

If you've found no suitable wesnoth.something function then there's no way yet apparently...

Then I can't add alignment key. I hoped that I simply overlooked it, but this time it wasn't my mistake (once in a lifetime )

If you need units_to_harm later on make a variable

No, it's needed only in the cycle for.

I has always been this way afaik.

Ah, OK. Thanks for all your clarifications!
If I'll have some other questions, or make some other stuff, I'll post here, of course.

[Anonymissimus]

EDIT: this mean that I'll have to install SVN, right?

yes

harm_amount is not supposed to be cleared, but instead stored as WML variable. Not a bug, a feature.

It's not a variable specifically requested by the wml coder as opposed to the other variable-storing tags. It should behave like e.g. second_unit (in moveto events) and such, which are only valid until the end of the event. harm_amount however remains until teh end of the campaign unless cleared by the wml coder.

Then I can't add alignment key. I hoped that I simply overlooked it, but this time it wasn't my mistake (once in a lifetime )

You could do wesnoth.get_locations for all locs matching the alignment= key and then look in the obtained array for the unit's hex but it'd be very inefficient. I guess I could make a function available in the lua interface but you need to wait until next 1.9 release unless you compile yourself.

[Elvish_Hunter]

It's not a variable specifically requested by the wml coder as opposed to the other variable-storing tags. It should behave like e.g. second_unit (in moveto events) and such, which are only valid until the end of the event. harm_amount however remains until teh end of the campaign unless cleared by the wml coder.

It should. But by looking to mainline wml-tags and helper (not so easy, for a beginner like me) I wasn't able to find any reference to second_unit. I tried also adding the value to wesnoth.current.event_context, either by using table.insert or directly, obtaining an error "table expected, got userdata". So, I suppose that such auto-storing (unit, second_unit, x1, x2...) are still managed by C++, that means: I have no idea, for now at least, on how to make harm_amount behave like second_unit.

You could do wesnoth.get_locations for all locs matching the alignment= key and then look in the obtained array for the unit's hex but it'd be very inefficient.

I imagined this alignment to, in fact, assign alignment to the damage itself, that is if [harm_unit] has alignment=chaotic, and happens during daytime, damage will be reduced by 25%, like if done by a chaotic unit. I wonder, however, like this key will work with liminal alignment, or with 24-hour ToD...
I guess that I'll wait for your function, or for me to have a good idea on this.

[silene]

I imagined this alignment to, in fact, assign alignment to the damage itself, that is if [harm_unit] has alignment=chaotic, and happens during daytime, damage will be reduced by 25%, like if done by a chaotic unit. I wonder, however, like this key will work with liminal alignment, or with 24-hour ToD...
I guess that I'll wait for your function, or for me to have a good idea on this.

Concerning alignment (and it would also subsume resistance computation), you could perhaps create a dummy unit with a given alignment and a given damage type, and then throw it at the to-be-damaged unit (LuaWML:Units#wesnoth.simulate_combat.) I guess the easiest way to interpret the result of the simulation would be to give the dummy unit 100% cth, a dummy range, and a single attack.

[Elvish_Hunter]

Thanks silene. For what I understood, at this point, is better to remove the alignment= key idea, to make this code simpler to maintain.
There is still one question, however: there is any way to make harm_amount automatically cleared at the end of the event in which [harm_unit] is used? If not, I think that I'll add a key "output=yes/no", with default no (that is, if no key given it will be nil), so it will be up to the campaign/UMC/whatever author to decide if have the damage stored in variable harm_amount or not.
Thanks again, to you and Anonymissimus, for your support!

[Anonymissimus]

I'd just do
if cfg.variable then wesnoth.set_variable(cfg.variable, ...) else ...

No, there's not (yet) any way.

[Elvish_Hunter]

if cfg.variable then wesnoth.set_variable(cfg.variable, ...) else ...

Yes, I thought about this possibility. I'll do this way.

No, there's not (yet) any way.

Good to know.
Now, I'll correct this tag to add the variable= key, test it and try to make a patch.

EDIT: tag corrected, here there is the new code.

Spoiler:

Code: Select all

function wml_actions.harm_unit(cfg)
	local amount=tonumber(cfg.amount) or helper.wml_error("[harm_unit] missing required amount= attribute")
	local damage
	local damage_type=(cfg.damage_type)
	local scroll=(cfg.scroll)
	local variable = (cfg.variable)
	local units_to_harm = helper.get_child(cfg, "filter") or helper.wml_error("[harm_unit] missing required [filter] tag")

	if not units_to_harm then return end

	for index, unit_to_harm in ipairs(wesnoth.get_units(units_to_harm)) do

		if damage_type then
			damage= (amount / 100) * wesnoth.unit_resistance(unit_to_harm, tostring(damage_type))
		else
			damage = amount
		end

		damage=math.floor(damage)
		unit_to_harm.hitpoints = unit_to_harm.hitpoints - damage

		if scroll then
			wesnoth.scroll_to_tile(unit_to_harm.x, unit_to_harm.y, true)
		end

		wesnoth.float_label(unit_to_harm.x, unit_to_harm.y, string.format("<span foreground='red'>%d</span>", damage))

		if scroll then
			wesnoth.fire("delay", {time="500"})
		end

		if unit_to_harm.hitpoints <= 0 then
			wesnoth.fire("kill", {id=unit_to_harm.id, animate="yes", fire_event="yes"})
		end

		if variable then
			wesnoth.set_variable(variable, damage)
		end

		wml_actions.redraw {}
	end
end

I added the variable key, and also a scroll= key, that, if enabled, scrolls to each unit before harming it. Final question: I rounded damage with math.floor. Considering that, in Wesnoth, even with 100% resistance, every successful blow deals at least 1 damage, should I have used math.ceil, or

Code: Select all

damage=( (amount / 100) * wesnoth.unit_resistance(unit_to_harm, tostring(damage_type))) or 1 --untested

or another, more complex, structure? (Anyway, I think that it'll be quite rare that someone will try to cast fire damage upon an Armageddon Drake, that with both math.ceil and floor will be 0...)
After that, I think that it will be ready for the patch.

[Anonymissimus]

Here's a patch, making
local time = wesnoth.get_time_of_day(10, 10)
available. time is the time's id string then. When I find out more about the secrets of returning a table there may be mroe info.
For compiling I suggest Crab's cmake+MSVC 9 strategy, that's the easiest one, especially since you know how .bat files work.

time_of_day.patch

(1.28 KiB) Downloaded 648 times

[Elvish_Hunter]

Thanks for your patch, but I decided to not add the alignment key, at least for now, mainly because we have at least three different ToD tables around (default, two suns, 24 hour, and users can define new ToD in WML). So, to add it, the best solution will be having a function that gets not only the ToD ID, but also its liminal_bonus and lawful_bonus keys.

For compiling I suggest Crab's cmake+MSVC 9 strategy, that's the easiest one, especially since you know how .bat files work.

I decided to go for the even easier way: Ubuntu 10.04 LTS, secondary Linux machine, svn diff>harm_unit.patch to the Terminal. For now, my main machine will remain Windows, also because I have still a lot of things to learn in Linux, but at least I have a secondary system just in case.
Anyway, here there is my patch and my wiki description (feel free to correct it), I'll upload the patch also on Gna.
EDIT: patch uploaded on Gna as #2230.

harm_unit.patch

Feel free to correct it if needed.

(1.85 KiB) Downloaded 751 times

Spoiler:

To change:
- FutureWML, remove [harm_unit] from list
- DirectActionsWML, add [harm_unit]

[harm_unit]
Harms a unit. If unit goes to 0 or less HP, it is killed.

[filter]: StandardUnitFilter, all matching units will be harmed (required).
amount: the amount of damage that will be done (required).
damage_type: if present, amount will be altered by unit resistance to the damage type specified.
scroll: if set to yes, scrolls to the unit before harming it.
variable: if present, the damage caused to the unit, altered by resistances, will be stored in a variable with the given name.

[Anonymissimus]

-you don't need () around cfg.something
-tonumber(args) returns nil in case args is there but can't be converted so change the error message to something more general
-the filter tag should be left away as in your previous versions I think, that extra key's don't harm
-the line
if not units_to_harm then return end
does nothing, you already check whether it is nil
-d in string.format stands for digit iirc, that is, damage >= 10 is not correctly handled
-use wml_actions.tag(...), not wesnoth.fire("tag", ...); the ladder is deprecated
-there's a wesnoth.delay function; I'd prefer wesnoth.tag over wml_actions.tag if there is a suitable function
-if you do the cfg.scroll option I'd make the delay time an argument too (magic numbers are bad)
-use unit_to_harm.valid, see this:

Code: Select all

		wesnoth.put_unit({ type = "Troll", x = 20, y = 10 })
		local troll = wesnoth.get_units({ x = 20, y = 10 })[1]
		wml_actions.kill({ x = 20, y = 10 }) -- this may be done by a fired event for a unit which is still to be iterated on
 		local x = troll.x -- error since the reference "troll" is no longer valid

[Elvish_Hunter]

-the filter tag should be left away as in your previous versions I think, that extra key's don't harm

I made it this way to match the behaviour of [heal_unit], that requires a [filter] tag.

-d in string.format stands for digit iirc, that is, damage >= 10 is not correctly handled

Copying from my Lua reference:

Formatting field types
%d decimal integer

-use wml_actions.tag(...), not wesnoth.fire("tag", ...); the ladder is deprecated
-there's a wesnoth.delay function; I'd prefer wesnoth.tag over wml_actions.tag if there is a suitable function

Am I wrong, or wml_actions.kill and wesnoth.delay are completely undocumented in LuaWML? And here, there isn't written that wesnoth.fire is deprecated.Thanks for warning me.

-if you do the cfg.scroll option I'd make the delay time an argument too (magic numbers are bad)

OK, but 500 will remain as default value.

-use unit_to_harm.valid, see this:

I don't (yet) understand how this may happen, considering that I check for unit ID to kill, but fixed anyway.
Here there is a corrected version, it seems to work, if it's fine I'll upload it again on Gna.

Spoiler:

Code: Select all

function wml_actions.harm_unit(cfg)
	local amount = tonumber(cfg.amount) or helper.wml_error("[harm_unit] has missing or wrong required amount= attribute")
	local damage
	local damage_type = cfg.damage_type
	local delay = cfg.delay or 500
	local scroll = cfg.scroll
	local units_to_harm = helper.get_child(cfg, "filter") or helper.wml_error("[harm_unit] missing required [filter] tag")
	local variable = cfg.variable

	for index, unit_to_harm in ipairs(wesnoth.get_units(units_to_harm)) do

		if damage_type then
			damage = (amount / 100) * wesnoth.unit_resistance(unit_to_harm, tostring(damage_type))
		else
			damage = amount
		end

		damage = math.floor(damage)

		if  unit_to_harm.valid then
			unit_to_harm.hitpoints = unit_to_harm.hitpoints - damage

			if scroll then
				wesnoth.scroll_to_tile(unit_to_harm.x, unit_to_harm.y, true)
			end

			wesnoth.float_label(unit_to_harm.x, unit_to_harm.y, string.format("<span foreground='red'>%d</span>", damage))

			if unit_to_harm.hitpoints <= 0 then
				wml_actions.kill({id = unit_to_harm.id, animate = "yes", fire_event = "yes"})
			end

			if scroll then
				wesnoth.delay(delay)
			end

			if variable then
				wesnoth.set_variable(variable, damage)
			end

			wml_actions.redraw {}
		end
	end
end

[Anonymissimus]

Am I wrong, or wml_actions.kill and wesnoth.delay are completely undocumented in LuaWML? And here, there isn't written that wesnoth.fire is deprecated.Thanks for warning me.

All action tags (C++ ones and lua ones) are available as wml_actions.tag().
It's not quite deprecated yet - look in compatibility-1.8.lua.

This breaks your current code:

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	[event]
		name=start
		{GENERIC_UNIT 1 Troll 1 1}
		{GENERIC_UNIT 1 Troll 2 2}
		[harm_unit]
			[filter]
			[/filter]
			amount=200
		[/harm_unit]
	[/event]
	[event]
		name=die
		[kill]
		[/kill]
	[/event]

[Elvish_Hunter]

All action tags (C++ ones and lua ones) are available as wml_actions.tag().

Thanks for the information.

This breaks your current code:

So, I did some experiments, and this happens because after killing the unit with [kill], [harm_unit] cannot longer find it.
I have no good ideas on how to fix it, at the moment (and this can be understandable, considering that until two weeks ago I never wrote custom tags); if you have an idea, can you kindly suggest me how to fix it?