In the GRT Modules are libraries containing a list of functions that are exported for use by code in other modules, scripts, or Workbench itself. Modules can be written in C++ or Python, but the data types used for arguments and the return value must be GRT types.
GRT modules are similar to Python modules, but are imported from
grt module, instead of directly
from an external file. The list of modules loaded into the
grt module is obtained from
grt.modules. Modules can be imported in Python
using statements such as
from grt.modules import
To export functions as a module from Python code, you must carry out the following steps:
The source file must be located in the user modules folder. This path is displayed in the Workbench Scripting Shell with the label Looking for user plugins in.... It is also possible to install the file using the main menu item Scripting, Install Plugin/Module File.
The source file name must have the extension
_grt.py; for example,
Some module metadata must be defined. This can be done using
DefineModule function from the wb
from wb import * ModuleInfo = DefineModule(name='MyModule', author='Your Name', version='1.0')
Functions to be exported require their signature to be declared. This is achieved using the export decorator in the previously created ModuleInfo object:
@ModuleInfo.export(grt.INT, grt.STRING) def checkString(s): ...
export statement, the return type
is listed first, followed by the input parameter types,
specified as GRT typenames. The following typenames can be
grt.INT: An integer value. Also used
for boolean values.
grt.DOUBLE: A floating-point numeric
grt.STRING: UTF-8 or ASCII string data.
grt.DICT: A key/value dictionary item.
Keys must be strings.
grt.LIST: A list of other values. It is
possible to specify the type of the contents as a tuple in
<type-or-class>). For example, (grt.LIST,
grt.STRING) for a list of strings. For a list of table
objects, the following would be specified:
grt.OBJECT: An instance of a GRT object
or a GRT class object, from
These types are defined in the
module, which must be imported before they are available for
The following code snippet illustrates declaring a module that exports a single function:
from wb import * import grt ModuleInfo = DefineModule(name='MyModule', author="your name", version='1.0') @ModuleInfo.export(grt.DOUBLE, grt.STRING, (grt.LIST, grt.DOUBLE)) def printListSum(message, doubleList): sum = 0 for d in doubleList: sum = sum + d print message, sum return sum