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. Here we only provide enough information, hopefully, to demystify NodeBrain modules for those installing or using an existing module. A NodeBrain Library manual describing the API has been started, but needs a lot work.

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.

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 Guide

[3] NodeBrain Tutorial

[4] NodeBrain Language

[5] NodeBrain Library