EAthena Scripting Standards

From TheManaWorld
Jump to: navigation, search

This is an attempt to standardize the eAthena coding. Any suggestions are welcome to be posted on the discussion page before editing.

Code Formatting

Indentation

  • Code is indented with four spaces.
  • Code in the same block should have the same indentation.
  • Labels have no indentation.
  • Menu options are on their own lines and are indented further.

Example:

menu
    "Yes.", L_Yes,
    "No.", L_No;
  • When using an if-statement, there should be a line break after the condition and the conditional command should be indented further. An exception to this is a series of if-statements at the beginning of a major code block which use gotos to jump to the correct position in the script. In this case the goto should be in the same line as the if-statement.

Example:

// if-statement and conditional command in the same line, gotos aligned
if (@quest >= 3) goto L_Done;
if (@quest == 2) goto L_Progress;
if (@quest == 1) goto L_Question;

// conditional command in the next line and indented further
if (BaseLevel < 40)
    set @cost, 100;

Whitespaces

In many places whitespaces can increase readability. Examples are

  • When concatenating text and variables:
mes "\"Hello " + strcharinfo(0) + "!\"";

instead of

mes "\"Hello "+strcharinfo(0)+"!\"";
  • When assigning values to variables:
set @var, 3;

instead of

set @var,3;
  • In menus:
menu
    "Yes.", L_Yes,
    "No.", L_No;

instead of

menu
    "Yes.",L_Yes,
    "No.",L_No;

Code Blocks

  • Code blocks should be separated from the others in a dinstinct way: insert a blank line between code blocks.
  • Individual blocks should be together No blank lines within a block.
  • The opening brackets should be at the end of the parent line, not in a new line; the closing ones should be in a line of their own.
  • A 'menu' must not be in the body of an if statement. Instead, goto a new block for the menu, or negate the logic and goto somewhere else if the label should not be shown.
  • The 'next' command goes at the end of a block (before a goto or fallthrough), never at the beginning. Make sure 'next' is never followed by something that leads to a 'close' without intervening text.

Labels and Subfunctions

  • Labels should be named in this way: L_CamelCase
  • Subfunctions should be named in this way: S_CamelCase
  • Labels should always start with L_, except those that act as a subfunction, which should start with S_
  • Newline before every label
  • No newline after a label
  • There must not be a fallthrough or goto to a subfunction label.
  • A subfunction label must not goto a normal label. It may, however, goto another label that is specific to that subfunction, and eventually reach a return.

Comments

At the beginning of a script file there should be documented

  • who is the author
  • the purpose of the script
  • which variables are used and what's their purpose
  • any additional information that can help to understand the script

Example:

// Author: devxy
// This file contains the NPC John, who is part of the Example quest.
// Quest states are saved in Quest_Example.
// State 1: started the quest
// State 2: did the next step
[...]

Within the script there should be comments if there are parts which might be difficult to understand.

In some of the older scripts there are boxed comments used like this:

//#################################################################################
//# NPC John - By Smith                                                           #
//#                                                                               #
//#  ...                                                                          #
//#################################################################################

Don't use them in new scripts.

Variables

Document Variables

in every file, document every variable as one of:

  • # account variable (prefix #) (note that there are also ## variable which didn't work in the stable version of the server)
  • permanent player variable (no prefix)
  • @ temporary player variable (prefix @) - used after the script close;s or end;s.
  • @ dynamic player variable (prefix @) - passed into or out of callsub or callfunc
  • @ lexical (local) player variable (prefix @) - used only within the function (scripthelp.txt documents that ".@" means this but I don't know if that works)
  • @ local constant (prefix @) - not dependent on the player, used only within the function. e.g. lots of @QUEST_FOO_{SHIFT,MASK}
  • $ global permanent variable (prefix $) (I'm not sure if we have any of these right now)
  • $ npc permanent variable (prefix $) same as above but only used by one NPC
  • $ global temporary variable (prefix $@)
  • $@ npc temporary variable (prefix $@) same as above but only used by one NPC, scripthelp.txt mentions prefix "." but I don't know if that works
  • special variable (in db/const.txt with a 1 following)
  • global constant (in const.txt)

If we use a consistent method of documenting these, we can then generate a list of all variables by type.

Variables initialization

Check for troublesome arrays: A troublesome array is defined as an array that is not

  • initialized all at once
  • initialized by appending elements to the end, for use in a menu
Nothing needs to be done, merely document them. I want this information at hand when I design the new scripting language to minimize conversion pains.
I wouldn't be surprised if there were no troublesome arrays at all. If there are only a couple it might be worth refactoring the code to remove them, but that might be a  high-level decision which is beyond the scope of this proposal.

Set dynamic and local @variables to 0 before close;

Naming Variables

Using as little variables as you need

So there are some quests, which require lots of variables. Think of monster oil quest, Oric and Warum quest etc.

This can often be done by bitmasking: One variable has 32 bits. So a variabe can store 2^32 different numbers: 4294967296

But sometimes you only need numbers from 0 to 15, but more of these variables. but numbers in range 0 to 15 can be stored in 4 bits ( 2^4 = 16 different numbers)

Here is an example how to use bitmasking: Media:Tester.txt

Defining Map Objects

These sections describe how to define map objects.

Warp Definitions

Shouldn't be done manually. Warps are what move players between maps. They can also be used to move players around a single map, if needed. Warps are defined like this:

map1,startX,startY|warp|name|width,height,map2,endX,endY

Key:

map1 the starting map
startX the x-coordinate of the starting warp tile
startY the y-coordinate of the starting warp tile
name the name of the warp, unused but must be defined
width the width of the warp
height the height of the warp
map2 the ending map
endX the x-coordinate of the tile the player will end up on
endY the y-coordinate of the tile the player will end up on

Width and height are described in detail here: Warp Details.

Monster Definitions

Shouldn't be done manually. Monsters are defined like this:

<map name>,<x>,<y>,<width>,<height>|monster|<name>|<mobID>,<count>,<spawn1>,<spawn2>,{<eventcode>}
map name the map the monsters should appear on
x the x-coordinate of the spawn tile
y the y-coordinate of the spawn tile
width the tile width of the spawn area
height the tile height of the spawn area
name the name of the mob, unused but must be defined. DO NOT use the keywords such as "spawn" in this name to avoid conflict with other game systems (magic for example)
mobID the mob identifier of the desired monster (in the monster db)the number to spawn
count the number to spawn
spawn1 the minimum delay between successive spawns (per individual)
spawn2 the minimum delay between death and respawn (per individual)
eventcode the script event to fire upon death

A detailed description of position and area can be found here: Mob Details.

NPC Definitions

<map name>,<x>,<y>,<facing>|script|<Name>|<spriteID>,{<code>}
<map name>,<x>,<y>,<facing>|script|<Name>|<spriteID>,<triggerX>,<triggerY>,{<code>}
map name the map the monsters should appear on
x the x-coordinate of the spawn tile
y the y-coordinate of the spawn tile
facing Direction the NPC faces to. It must be set to 0 in TMW
height the tile height of the spawn area
Name the name of the NPC
spriteID the mob identifier of the desired NPC. Sprite ID
triggerX
triggerY
eventcode the script event to fire upon death
  • Server side :
NPC definitions (script) are usually stored as :
(tmwa-server-data/)world/map/npc/<map name>/<NPC Name>.txt or in the file :
(tmwa-server-data/)world/map/npc/<map name>/npc.txt
  • Client side :
The NPC is associated with a sprite (the image that will appear in the game), and a XML file which tells the client some display parameters.
(tmwa-client-data/)graphics/sprites/npcs/npc-<Name>.png
(tmwa-client-data/)graphics/sprites/npcs/npc-<Name>.xml
The NPC spriteID is linked to graphic files and XML in the file : (tmwa-client-data/)npcs.xml


Script Functions

function|script|<function name>|{<code>}

Actual script functions are stored or imported in the files : (tmwa-server-data/)world/map/npc/functions/<function name>.txt, regardless rhey are called from a Map, NPC, Mob or item.

Script Loading

The main script import file is:(tmwa-server-data/)world/map/npc/scripts.conf
It loads (tmwa-server-data/)world/map/npc/_import.txt which imports all NPC scripts wich are stored under the respective map name folders, usually under NPC name.

Examples

Open a chest and get reward

An example is given by a quest to get a key for a chest (in fact 3 keys):

// A treasure chest. You need three keys to open it.
//
// TMW_Quest (document variable here)
//

002-4.gat,93,37,0|script|Treasure|111,{

    if (TMW_Quest >= 38) goto L_Finished;

    mes "There is a chest here.";
    mes "Do you want to try to open it?";
    next;
    menu
        "Yes.", L_Yes,
        "No.", -;
    close;

L_Yes:
    if(countitem("TreasureKey") < 3)
        goto L_Not_Enough;
    getinventorylist;
    if (@inventorylist_count == 100 && countitem("TreasureKey") > 3)
        goto L_TooMany;
    mes "You opened the chest and found a short bow!";
    delitem "TreasureKey", 3;
    getitem "ShortBow", 1;
    set TMW_Quest, 38;
    close;

L_Not_Enough:
    mes "It seems that you do not have the right key for this chest yet...";
    close;

L_Finished:
    mes "You have already opened this chest.";
    close;

L_TooMany:
    mes "You do not have enough room to loot this chest. Maybe you should try again later.";
    close;
}

This script starts with describing the NPC (the chest, NPC sprite 111) and its location (map 002-4 X=93, Y=37, in tiles from top left of the map). Then follows what happens on activation: First, the variable "TMW_Quest" is checked to know if the player already accomplished the quest (the variable should be documented), If he has the script continues at label L_Finished, the player is reminded fe alredy accomplished the task and script finishes, if not the scrip continues. A message is shown (mes), then an option dialog (menu) is displayed with two possible answers : "Yes." or "No.". If the player answers "No." the script stops (close;); if he answers "Yes." the script continues at label L_Yes. Now player is checked to know if he has at least 3 keys, if not script branches to label L_Not_Enough tells the player he "has not the right key" and script closes. If he has keys enough, his inventory list is retrieved by the built-in function "getinventorylist" and it's content is checked to know if the player will have room enough to store the reward after the 3 keys use. If not, script goes to label L_TooMany and script close after a warning message, If yes 3 keys are deleted in player's inventory, he gets the reward: a Short Bow and the variable TMW_Quest is set to 38.

For more examples of the current system, check out the current scripts in use by the server. Beware though, this could affect your enjoyment of the game as it does spoil some of the mystery. Here's a link to git so you can view them in your browser:

https://github.com/themanaworld/tmwa-server-data/tree/master/world/map/npc

Note that anything said by an NPC should be put in double quotes ("). You can do that like this: "\"Hello!\" she said."

References