Variable

Description

A general-purpose variable, used to store experiment parameters, collect results, and mediate the transfer of data between components

Signature

variable

Alias

var (MWEL only)

Required Parameters

default_value

Example

0

Initial value assigned to the variable when the experiment is loaded

Optional Parameters

scope

Options
global
local
Default

global

Controls the visibility of changes made to the variable’s value.

If a variable has local scope, then changes to its value are visible only within the paradigm component in which the assignment was made. These local changes persist between executions of the paradigm component.

If a variable has global scope, changes to its value are visible everywhere.

logging

Options
never
when_changed
Default

when_changed

Determines when the variable’s value is written to the event stream (and thereby the data file)

persistant

Default

NO

If YES, then the variable’s value is included in saved variable sets created via MWClient

exclude_from_data_file

Default

NO

If YES, then the variable’s value is not written to the data file. Other event stream listeners (e.g. MWClient, client- and server-side conduits) continue to receive its value.

groups

Comma-separated list containing the names of groups to which the variable belongs. Variable groups are displayed as expandable sections in MWClient’s variables window.

Deprecated Parameters

type

Options
any
boolean
integer
float
string
list
Default

any

Controls how the content of default_value is interpreted. When set to any (recommended), the default value is parsed like a normal expression, and the parser infers its type.

Placement

Allowed at top level:

Yes

Allowed parent:

Folder

Allowed children:

Action