Bukkit

Sve is a dynamic scripting language comparable to Lua and JavaScript. Sve can be used for making more intelligent redstone systems, minigames and small plugins. It is also a handy calculator.

Quick start

1. Download sve.zip.
2. Extract Sve.jar to the plugins folder.
3. Extract svefiles folder to the server root folder (the folder where the plugins folder is).
4. Execute command /svefile svefiles/all.sve. It must be executed when server starts to load all libraries.
5. Read the Sve tutorial

Please see these pictures:

• the root folder
• svefiles folder

See Examples for example programs. See also alias.sve, the first ever sve program released in bukkit.org.

Introduction to the Sve programming language

Sve is a dynamic garbage collected scripting language.

 # variables
 local a = 2
 local b = a + 1
 a++
 
 # control structures
 if: a == b {
    print("a is b")
 }
 a = -4
 while: a < b {
     a++
     print("a: " + a)
 }
 
 # functions
 def: f {
     print("in f()")
     return 0
 }
 def: add2(n) {
     return n + 2
 }
 f()
 print(add2(3))

Sve is easy, just read more about it. Sve tutorial

Example

Lets players to send anonymous messages to the chat.

 registercommand("say", "svesay", def {
 	local command = ""
 	foreach($$["$args"])::def (arg) command = command + " " + arg
 	
 	foreach(@a)::def (p) {
 		if: hasperm(p, "svesay.spy") p.sendMessage_String("§5[§dchat.sve§5]§e " + @m + " said:§f" + command)
 		else: p.sendMessage_String("§5[§dRandom voice§5]§e" + command)
 	}
 })

Svesay script uses svecommands, a way to give untrusted persons a limited access to sve. Above script registers one command, "say" which needs "svesay" permission. Everybody who has that permission can send anonymous messages using /svecommand -command.

/svecommand say The message is here.

Admins who have permission "svesay.spy" can see the message senders.

$$["$args"] is an array, which contains all arguments given to the function. Foreach loop is used to concatenate all arguments together.

Commands and permissions

• /sve <code> – executes sve code from chat – serverq.sve
• /svefile <file path> – executes sve code from a file – serverq.svefile
• /svestop – stops all sve threads (timers, see timer() function) – serverq.svestop
• /svecommand <command name> <arguments> – runs a svecommand, must be registered using registercommand() function) – serverq.svecommand

Security

Sve is designed to be used by administrators only. There are many functions which can be used to gain higher access. For example, system function can be used to execute commands as the system (from console) and exec function can be used to execute commands as an other player. There is no way to limit these commands to just admins.

Functions can be removed from the environment by setting them to nil. In Sve functions are variables.

 system = nil
 exec = nil

Remember, if there are dangerous functions in the environment do not give untrusted persons an access to Sve. Potentially dangerous functions are in addition to system and exec timer, eval, getServer, players and worlds. Methods of @m, @a and @w are also dangerous, as they can be used to modify players settings and environment.