GetVariable
Script function

world.GetVariable

DOC_scripting Read about scripting

Type

Method

Summary

Gets the contents of a variable

Prototype

VARIANT GetVariable(BSTR VariableName);

DOC_data_types View list of data type meanings

Description

Gets the contents of the named variable. If the named variable does not exist, EMPTY is returned. If the name given is invalid, NULL is returned. (Use "IsEmpty" and "IsNull" to test for these possibilities).

If GetVariable is called from within a plugin, the variables for the current plugin are used, not the "global" MUSHclient variables.

If you want to find the value of a variable in another plugin, or the global MUSHclient variables, use "GetPluginVariable".


-----

RULES FOR NAMES

Names of triggers, aliases, timers and variables must follow these rules:

a. Start with a letter (A-Z)
b. Be followed by letters (A-Z), numbers (0-9) or the underscore character (_)


-----

SAVING AND LOADING

Please note that the following characters will not be handled correctly:

* The byte value hex 00 (otherwise known as 0x00 or null). This is used as a string terminator in MUSHclient, and attempts to imbed 0x00 values into variables will result in the variable being terminated at the 0x00 position.


* Carriage-return (hex 0D or 0x0D) and line-feeds (hex 0A or 0x0A). You can use these internally however you like, however when they are read from a plugin state file, or a MUSHclient world file, carriage returns are dropped, and line-feeds are converted to the sequence 0x0D 0x0A (carriage-return followed by linefeed). This is not normally a problem - because line breaks are usually stored as carriage-return/linefeed, and the reading process effectively will read them back in as that. However individual carriage-returns or linefeeds will not be read back in correctly.


If you are planning to use variables to store "binary" data - that is, data that can have all 256 possible character values, you are advised to convert them to base-64 encoded strings (using Base64Encode) when saving them, and conver them back (using Base64Decode) when loading them. Also be aware that only the Lua version of the base 64 encoding (utils.base64encode and utils.base64decode) will correctly handle the 0x00 value.

-----

RETRIEVING NUMBERS

Variables are stored as strings, so GetVariable returns a string, not a number. If the variable is supposed to be storing a numeric quantity (a count of mobs, hit points, or experience, for example) then you will probably need to convert it back to a number if it is going to be correctly processed inside a script. For example:

Lua: x = tonumber (GetVariable ("x"))
JScript: x = parseInt (GetVariable ("x"))
Python: x = int (GetVariable ("x"))
VBscript: x = CInt (GetVariable ("x"))

These examples retrieve the variable "x" and use the "convert to number" function of the script language to convert it back into a script numeric variable.

VBscript example

dim MyName

MyName = world.GetVariable ("MyName")

if isempty (MyName) then
  world.note "My name is not defined"
end if

if isnull (MyName) then
  world.note "Invalid variable name"
end if

world.note MyName


Jscript example

var MyName;

MyName = world.GetVariable("MyName");

if (MyName == null)
  world.note("MyName is not defined");
else
  world.note(MyName);


PerlScript example

$MyName = $world->GetVariable("MyName");

if (!defined ($MyName)) 
  {
  $world->note ("MyName is not defined");
  }
else 
  {
  $world->note ($MyName);
  }


Python example

MyName = world.GetVariable("MyName")

if not MyName:
  world.note("MyName is not defined")
else:
  world.note(MyName)


Lua example

local MyName

MyName = GetVariable("MyName")

if MyName == nil then
  Note ("MyName is not defined")
else
  Note (MyName)
end


Lua notes

Lua returns nil where applicable instead of an "empty variant" or "null variant".


Return value

The contents of the specified variable.
An EMPTY variant, if the variable does not exist.
A NULL variant if the variable name is invalid.



See Also ...

Topics

DOC_Arrays Arrays
DOC_plugins Plugins
DOC_scripting Scripting
DOC_variables Variables

Functions

FNC_DeleteVariable DeleteVariable (Deletes a variable)
FNC_GetEntity GetEntity (Retrieves the value of an MXP server-defined entity)
FNC_GetPluginVariable GetPluginVariable (Gets the contents of a variable belonging to a plugin)
FNC_GetPluginVariableList GetPluginVariableList (Gets the list of variables in a specified plugin)
FNC_GetVariableList GetVariableList (Gets the list of variables)
FNC_SetVariable SetVariable (Sets the value of a variable)

(Help topic: function=GetVariable)

DOC_contents Documentation contents page