int skillAssert (nbCELL context , void * skillHandle , void * knowledgeHandle , nbCELL arglist );

nbCELL skillEvaluate (nbCELL context , void * skillHandle , void * knowledgeHandle , nbCELL arglist );

void * skillBind (nbCELL context ,nbCELL skill ,nbCELL arglist ,char * text ){

nbSkillSetMethod( context , skill ,NB_EXPERT_ASSERT, skillAssert ); nbSkillSetMethod( context , skill ,NB_EXPERT_EVALUATE, skillEvaluate ); ... create skillHandle here using arglist and text ... return( skillHandle ); }

declare module module path/nb_mod_package.(so|dylib|dll);

declare module module [ {"path"} ] [ package [ (args) ] [ ; | :text ]

declare skill skill [ module. ] skill [ (args) ] [ ; | :text ]

define term node [ skill [ (args) ] ] [ ; | :text ]

You will not find enough information here to learn how to write a node module. For that, you will need to study the NodeBrain API Reference. Here we only provide enough information, hopefully, to demystify NodeBrain modules for those installing or using an existing module.

See http://www.nodebrain.org for more information.

/usr/local/include/nb/nb.h	NodeBrain API header file.
/usr/local/lib/nb/x.x/nb_module.suffix	NodeBrain modules may be located anywhere, provided you direct nb to them using the NB_MODULE_PATH environment variable or a path in a module declaration command. If no path is specified and a module is not found using the native search path, NodeBrain checks in /usr/local/lib/nb/x.x as show above, where suffix is determined by the platform.
nb_mod_module.so	[Solaris and Linux]
nb_mod_module.sl	[HP-UX]
nb_mod_module.dylib	[Mac OS x]
nb_mod_module.dll	[Windows]

# declare module - unnecessary if the module is in the standard directory

declare tree module {"."}tree;

# declare skill - unnecessary if no special parameters are specified

declare tree skill tree:trace;

# table of critical devices

define criticalDevice node tree;

# table of problem devices

define problemDevice node tree;

# rules that respond when a device has a new problem

define event node;

event. define r1 if(type="problem" and ?problemDevice(device)) problemDevice(device):actionA

event. define r2 if(type="problem" and ?problemDevice(device) and criticalDevice(device)):actionB

event. define r3 if(type="restored") ?problemDevice(device);

# sample initialization of the critical device table

assert criticalDevice("abc");

assert criticalDevice("def");

# sample events from a monitoring application

event. alert type="problem",device="abc";

event. alert type="restored",device="abc";

NB_MODULE_PATH

The NB_MODULE_PATH environment variable provides a platform independent way of specifying a path for locating node modules. This path overrides the native system search paths by qualifying module names so that a search is avoided. The following example illustrates a setting that directs NodeBrain to search the current directory first and then the parent directory when loading modules (plug-ins). NB_MODULE_PATH="./:../" nb myscript.nb

yyyy/mm/dd hh:mm:ss NB000E Unable to load file

When a module is successfully loaded but the symbol referenced in a skill declaration is not found, a message is displayed.

yyyy/mm/dd hh:mm:ss NB000E Symbol symbol not found

NodeBrain does not attempt to load a module when it is declared. Instead, it waits until a module is referenced by a DEFINE command for a node to avoid loading modules unnecessarily. For this reason, either of the messages above will follow a node definition when there is an error.

Linux, Solaris, HP-UX, OS X, and Windows

For a complete and current list of bugs, you should refer to the project web site.

Please report bugs by linking to the project page from the home page, http://www.nodebrain.org, or send email to <bugs@nodebrain.org>.

[1] NodeBrain Home Page

[2] NodeBrain Tutorial

[3] NodeBrain User Guide

[4] NodeBrain Language Reference

[5] NodeBrain Module Reference

[6] NodeBrain API Reference