0MBEGIN-ENTRY-MAIN HELP_USAGE FUNCTION_SUMMARY RELEASE_NOTES COMMAND_SUMMARY CONSTRUCT_SUMMARY INTEGRATED_EDITOR END-ENTRY 1IBEGIN-ENTRY-HELP_USAGE HELP_USAGE H.2 Using the Help Facility The help facility displays menus of topics and prompts the user for a choice. It then references the help file for that information. The help facility can be called with or without a command-line topic. Syntax: (help []) where is the full path leading to a topic in the help tree. For example, for information on defrule syntax, the user would type: (help construct_summary defrule). The help function has no return value. Each element or field in the path is delimited by white space, and the help facility is not case sensitive. In addition, the entire name of a field does not need to be specified. Only enough characters to distinguish the field from other choices in the menu are necessary (if there is a conflict, the help facility will pick the first one in the list). For instance, (help con def) would be sufficient for the above example. A few special fields can be used while in the help facility. ^ Branch up one level. ? When specified at the end of a path, this forces a display of the current menu, even on branch-ups. Giving no topic field will branch up one level. A branch-up from the MAIN topic root node implies an exit from help. By default, the help facility comes up in the MAIN topic root menu and the user may make a choice as described above. The prompt line always displays the name of the current menu. The help facility will branch through the help- tree until instructed to exit by a branch-up from the top level. The level always is reset to the MAIN topic upon exit from the help facility. The first call to the help facility will take longer than successive calls while the system loads help information into an internal lookup table. All other calls to the help facility are very fast. The help facility reads help information from a file during execution. Users may wish to change the location of the help file to meet the configuration of their system. The help-path function was provided to allow this. Syntax: (help-path []) If no argument is specified, the function displays the name of the current help file. If an argument is specified, the help facility will use the new file name for future help references during this CLIPS session. To change the location of the help file permanently, a change must be made in the setup.h file, then CLIPS must be recompiled. The help-path function has no return value. END-ENTRY 1MBEGIN-ENTRY-RELEASE_NOTES RELEASE_NOTES The release notes help section contains information about new features and where to get technical support. Subtopics: NEW_FEATURES SUPPORT_INFORMATION END-ENTRY 2IBEGIN-ENTRY-NEW_FEATURES RELEASE_NOTES NEW_FEATURES Version 6.2 of CLIPS contains two major enhancements. First, CLIPS now provides a mechanism which allows an embedded application to create multiple environments into which programs can be loaded. Second, an improved Windows 95/98/NT CLIPS interface is now available and the Macintosh CLIPS interface has been enhanced to support MacOS X. For a detailed listing of differences between the 6.x releases of CLIPS, refer to appendix B of the Basic Programming Guide and appendix C of the Advanced Programming Guide. END-ENTRY 2IBEGIN-ENTRY-SUPPORT_INFORMATION RELEASE_NOTES SUPPORT_INFORMATION CLIPS executables, documentation, and source code are available for download from http://www.ghg.net/clips/download/. Questions regarding CLIPS can be sent via electronic mail to clips@ghg.net. An electronic conferencing facility, sponsored by Distributed Computing Systems (http://www.discomsys.com), is also available to CLIPS users. Subscribers to this facility may send questions, observations, answers, editorials, etc., in the form of electronic mail to the conference. All subscribers will have a copy of these messages reflected back to them at their respective electronic mail addresses. To subscribe, send a single line message to clips-request@discomsys.com containing the word "subscribe". The subject field is ignored but the address found in the ÔReply:Ő, ÔReply to:Ő, or ÔFrom:Ő field will be entered in the distribution list. Upon subscription you will receive a mail message instructing you how to participate in the conference from that point forward. Save this mail message. You may need the instructions later if you wish to unsubscribe from the list server. To send your own messages to members of the conference you need simply address your mail to clips@discomsys.com. Your message will be reflected to all other members of the conference. If you wish to remove yourself from the conference and discontinue receiving mail simply send a message to clips-request@discomsys.com with "unsubscribe" as the message text. If you want to unsubscribe using another email account than the one you subscribed with, then append the original subscribing email account to the text of the message. For example: "unsubscribe john.doe@account.net". Do not send unsubscribe messages to clips@discomsys.com! This sends a mail message to every member of the list. If you need to get in contact with the list administrator (for trouble unsubscribing or other questions about the list), send email to clips-owner @discomsys.com. Intelligent Software Professionals has made available the CLIPS-LIST archive, a WWW-based full text searchable archive containing over two years of question and answers directed to the CLIPS List Server. It can be accessed at the URL http://www.isphouston.com/swish-web.html. A CLIPS World Wide Web page can be accessed using the URL http://www.ghg.net/clips/CLIPS.html. Usenet users can also find information and post questions about CLIPS to the comp.ai.shells news group. The CLIPS Developers' Forum, a thread-based message board, is available at http://www.cpbinc.com/clips. This board exists to provide a site for discussion of research, development, and implementation of the CLIPS expert systems and related technologies. The hosting services for this web page are provided by CPB, Inc. Questions pertaining to this forum can be sent to jerry.gamble@cpbinc.com. END-ENTRY 1MBEGIN-ENTRY-CONSTRUCT_SUMMARY CONSTRUCT_SUMMARY This section gives a general overview of the available CLIPS constructs. Subtopics: DEFRULE DEFCLASS DEFFACTS DEFINSTANCES DEFTEMPLATE DEFMESSAGE-HANDLER DEFGLOBAL DEFMODULE DEFFUNCTION CONSTRAINT_ATTRIBUTES DEFGENERIC/DEFMETHOD END-ENTRY 2IBEGIN-ENTRY-DEFRULE CONSTRUCT_SUMMARY DEFRULE One of the primary methods of representing knowledge in CLIPS is a rule. A rule is a collection of conditions and the actions to be taken if the conditions are met. The developer of an expert system defines the rules which describe how to solve a problem. Rules execute (or fire) based on the existence or non-existence of facts. CLIPS provides the mechanism (the inference engine) which attempts to match the rules to the current state of the system (as represented by the fact-list) and applies the actions. (defrule [] [] * => *) DECLARATIONS ------------------------------------------------------------------ ::= (declare +) ::= (salience ) | (auto-focus ) CONDITIONAL ELEMENTS ------------------------------------------------------------------ ::= | | | | | | | |

::= (test ) ::= (not ) ::= (and +) ::= (or +) ::= (exists +) ::= (forall

+) ::= (logical +) PATTERN CONDITIONAL ELEMENT ------------------------------------------------------------------ ::= ? <-

::= | |

::= ( *) ::= (*) ::= (object *) ::= (is-a ) | (name ) | ( *) ::= |

::= |

::= ( ) ::= ( *) PATTERN CONSTRAINTS ------------------------------------------------------------------ ::= ? | $? |

::= | & | |

::= | ~ ::= | | | : | = END-ENTRY 2IBEGIN-ENTRY-DEFFACTS CONSTRUCT_SUMMARY DEFFACTS With the deffacts construct, a list of facts can be defined which are automatically asserted whenever the reset command is performed. Facts asserted through deffacts may be retracted or pattern matched like any other fact. The initial fact-list, including any defined deffacts, is always reconstructed after a reset command. The syntax of the deffacts construct is: (deffacts [] *) END-ENTRY 2IBEGIN-ENTRY-DEFTEMPLATE CONSTRUCT_SUMMARY DEFTEMPLATE Ordered facts encode information positionally. To access that information, a user must know not only what data is stored in a fact but which field contains the data. Non-ordered (or deftemplate) facts provide the user with the ability to abstract the structure of a fact by assigning names to each field found within the fact. The deftemplate construct is used to create a template which can then be used by non-ordered facts to access fields of the fact by name. The deftemplate construct is analogous to a record or structure definition in programming languages such as Pascal and C. The syntax of the deftemplate construct is: (deftemplate [] *) ::= |

::= (slot

*) ::= (multislot

*) ::= |

::= (default ?DERIVE | ?NONE | *) | (default-dynamic *) END-ENTRY 2IBEGIN-ENTRY-DEFGLOBAL CONSTRUCT_SUMMARY DEFGLOBAL With the defglobal construct, global variables can be defined, set, and accessed within the CLIPS environment. Global variables can be accessed as part of the pattern matching process, but changing them does not invoke the pattern matching process. The bind function is used to set the value of global variables. The syntax of the defglobal construct is: ::= (defglobal [] *) ::= =

::= ?** END-ENTRY 2IBEGIN-ENTRY-DEFFUNCTION CONSTRUCT_SUMMARY DEFFUNCTION With the deffunction construct, new functions may be defined directly in CLIPS. Deffunctions are equivalent in use to other functions in CLIPS. The only differences between user-defined external functions and deffunctions are that deffunctions are written in CLIPS and executed by CLIPS interpretively and user-defined external functions are written in an external language, such as C, and executed by CLIPS directly. Also, deffunctions allow the addition of new functions without having to recompile and relink CLIPS. The syntax of the deffunction construct is: (deffunction [] (* []) *) ::=

::= END-ENTRY 2IBEGIN-ENTRY-DEFGENERIC/DEFMETHOD CONSTRUCT_SUMMARY DEFGENERIC/DEFMETHOD With the defgeneric/defmethod constructs, new generic functions may be written directly in CLIPS. Generic functions are similar to deffunctions because they can be used to define new procedural code directly in CLIPS, and they can be called like any other function. However, generic functions are much more powerful because they can do different things depending on the types (or classes) and number of their arguments. For example, a '+' operator could be defined which performs concatenation for strings but still performs arithmetic addition for numbers. Generic functions are comprised of multiple components called methods, where each method handles different cases of arguments for the generic function. A generic function which has more than one method is said to be overloaded. A generic function is comprised of a header (similar to a forward declaration) and zero or more methods. A generic function header can either be explicitly declared by the user or implicitly declared by the definition of at least one method. The defgeneric construct is used to specify the generic function header, and the defmethod construct is used for each of the generic function's methods. The syntax of the defgeneric/defmethod constructs is: (defgeneric []) (defmethod [] [] (* []) *) ::= | ( * []) ::= ::= ::= | END-ENTRY 2IBEGIN-ENTRY-DEFCLASS CONSTRUCT_SUMMARY DEFCLASS A defclass is a construct for specifying the properties (slots) of a class of objects. A defclass consists of four elements: 1) a name, 2) a list of superclasses from which the new class inherits slots and message-handlers, 3) a specifier saying whether or not the creation of direct instances of the new class is allowed and 4) a list of slots specific to the new class. All user-defined classes must inherit from at least one class, and to this end COOL provides predefined system classes for use as a base in the derivation of new classes. Any slots explicitly given in the defclass override those gotten from inheritance. COOL applies rules to the list of superclasses to generate a class precedence list for the new class. Facets further describe slots. Some examples of facets include: default value, cardinality, and types of access allowed. The syntax of the defclass construct is: (defclass [] (is-a +) [] [] * *) ::= (role concrete | abstract) ::= (pattern-match reactive | non-reactive) ::= (slot *) | (single-slot *) | (multislot *) ::= | | | | | | |

::= (default ?DERIVE | ?NONE | *) | (default-dynamic *) ::= (storage local | shared) ::= (access read-write | read-only | initialize-only) ::= (propagation inherit | no-inherit) ::= (source exclusive | composite) ::= (pattern-match reactive | non-reactive) ::= (visibility private | public) ::= (create-accessor ?NONE | read | write | read-write) ::= (override-message ?DEFAULT | ) ::= (message-handler []) ::= primary | around | before | after END-ENTRY 2IBEGIN-ENTRY-DEFINSTANCES CONSTRUCT_SUMMARY DEFINSTANCES Similar to deffacts, the definstances construct allows the specification of instances which will be created every time the reset command is executed. On every reset all current instances receive a delete message, and the equivalent of a make-instance function call is made for every instance specified in definstances constructs. The syntax of the definstances construct is: ::= (definstances [] *) ::= () ::= of

* ::= ( *) END-ENTRY 2IBEGIN-ENTRY-DEFMESSAGE-HANDLER CONSTRUCT_SUMMARY DEFMESSAGE-HANDLER Objects are manipulated by sending them messages via the function send. The result of a message is a useful return-value or side-effect. A defmessage-handler is a construct for specifying the behavior of a class of objects in response to a particular message. The implementation of a message is made up of pieces of procedural code called message-handlers (or handlers for short). Each class in the class precedence list of an object's class can have handlers for a message. In this way, the object's class and all its superclasses share the labor of handling the message. Each class's handlers handle the part of the message which is appropriate to that class. Within a class, the handlers for a particular message can be further subdivided into four types or categories: primary, before, after and around. A defmessage-handler is comprised of seven elements: 1) a class name to which to attach the handler (the class must have been previously defined), 2) a message name to which the handler will respond, 3) an optional type (the default is primary), 4) an optional comment, 5) a list of parameters that will be passed to the handler during execution, 6) an optional wildcard parameter and 7) a series of expressions which are executed in order when the handler is called. The return-value of a message-handler is the evaluation of the last expression in the body. The syntax of the defmessage-handler construct is: (defmessage-handler

[] [] (* []) *) ::= around | before | primary | after ::=

::= END-ENTRY 2IBEGIN-ENTRY-DEFMODULE CONSTRUCT_SUMMARY DEFMODULE CLIPS provides support for the modular development and execution of knowledge bases with the defmodule construct. CLIPS modules allow a set of constructs to be grouped together such that explicit control can be maintained over restricting the access of the constructs by other modules. This type of control is similar to global and local scoping used in languages such as C or Ada. By restricting access to deftemplate and defclass constructs, modules can function as blackboards, permitting only certain facts and instances to be seen by other modules. Modules are also used by rules to provide execution control. The syntax of the defmodule construct is: ::= (defmodule [] *) ::= (export ) | (import

) ::= ?ALL | ?NONE | ?ALL | ?NONE |

+ ::= deftemplate | defclass | defglobal | deffunction | defgeneric END-ENTRY 2IBEGIN-ENTRY-CONSTRAINT_ATTRIBUTES CONSTRUCT_SUMMARY CONSTRAINT_ATTRIBUTES Constraint attributes can be associated with deftemplate and defclass slots so that type checking can be performed on slot values when template facts and instances are created. The constraint information is also analyzed for the patterns on the LHS of a rule to determine if the specified constraints prevent the rule from ever firing. The syntax for constraint attributes is: ::= Ę| | |

) ::= | ?VARIABLE ::= (cardinality

) ::= | ?VARIABLE END-ENTRY 1MBEGIN-ENTRY-FUNCTION_SUMMARY FUNCTION_SUMMARY This section gives a general overview of the available CLIPS functions. Subtopics: PREDICATE_FUNCTIONS DEFRULE_FUNCTIONS MULTIFIELD_FUNCTIONS AGENDA_FUNCTIONS STRING_FUNCTIONS DEFGLOBAL_FUNCTIONS IO_FUNCTIONS DEFFUNCTION_FUNCTIONS MATH_FUNCTIONS GENERIC_FUNCTION_FUNCTIONS PROCEDURAL_FUNCTIONS COOL_FUNCTIONS MISCELLANEOUS_FUNCTIONS DEFMODULE_FUNCTIONS DEFTEMPLATE_FUNCTIONS SEQUENCE_EXPANSION_FUNCTIONS FACT_FUNCTIONS END-ENTRY 2IBEGIN-ENTRY-PREDICATE_FUNCTIONS FUNCTION_SUMMARY PREDICATE_FUNCTIONS The following functions perform predicate tests and return either TRUE or FALSE. NUMBERP: Returns TRUE for integers and floats. (numberp ) FLOATP: Returns TRUE for floats. (floatp ) INTEGERP: Returns TRUE for integers. (integerp ) LEXEMEP: Returns TRUE for symbols and strings. (numberp ) STRINGP: Returns TRUE for strings. (stringp ) SYMBOLP: Returns TRUE for symbols. (symbolp ) EVENP: Returns TRUE for even numbers. (evenp ) ODDP: Returns TRUE for odd numbers. (oddp ) MULTIFIELDP: Returns TRUE for multifield values. (multifieldp ) POINTERP: Returns TRUE for external addresses. (pointerp ) EQ: Returns TRUE if the 1st argument is equal in type and value to all subsequent arguments. (eq +) NEQ: Returns TRUE if the 1st argument is not equal in type and value to all subsequent arguments. (neq +) =: Returns TRUE if the 1st argument is equal in value to all subsequent arguments. (=

+) <>: Returns TRUE if the 1st argument is not equal in value to all subsequent arguments. (<>

+) >: Returns TRUE if each argument is greater in value than the argument following it. (>

+) >=: Returns TRUE if each argument is greater than or equal to in value than the argument following it. (>=

+) <: Returns TRUE if each argument is less in value than the argument following it. (>

+) <=: Returns TRUE if each argument is less than or equal to in value than the argument following it. (<=

+) AND: Returns TRUE if all arguments evaluate to a non-FALSE value. (and +) OR: Returns TRUE if any argument evaluates to a non-FALSE value. (or +) NOT: Returns TRUE if its only argument evaluates to FALSE. (not ) END-ENTRY 2IBEGIN-ENTRY-MULTIFIELD_FUNCTIONS FUNCTION_SUMMARY MULTIFIELD_FUNCTIONS The following functions operate on multifield values. CREATE$: Appends its arguments together to create a multifield value. (create$ *) NTH$: Returns the specified field of a multifield value. (nth$

) MEMBER$: Returns the position of a single-field value within a multifield value. (member$

) SUBSETP: Returns TRUE if the first argument is a subset of the second argument. (subsetp

) DELETE$: Deletes the specified range from a multifield value. (delete$

) EXPLODE$: Creates a multifield value from a string. (explode$ ) IMPLODE$: Creates a string from a multifield value. (implode$ ) SUBSEQ$: Extracts the specified range from a multifield value. (subseq$

) REPLACE$: Replaces the specified range of a multifield value with a set of values. (replace$

+) INSERT$: Inserts one or more values in a multifield. (insert$

+) FIRST$: Returns the first field of a multifield. (first$ ) REST$: Returns all but the first field of a multifield. (rest$ ) LENGTH$: Returns the number of fields in a multifield value. (length$ ) DELETE-MEMBER$: Deletes specific values contained within a multifield value and returns the modified multifield value. (delete-member$ +) REPLACE-MEMBER$: Replaces specific values contained within a multifield value and returns the modified multifield value. (replace-member$

+) END-ENTRY 2IBEGIN-ENTRY-STRING_FUNCTIONS FUNCTION_SUMMARY STRING_FUNCTIONS The following functions perform operations that are related to strings. STR-CAT: Concatenates its arguments to form a single string. (str-cat *) SYM-CAT: Concatenates its arguments to form a single symbol. (sym-cat *) SUB-STRING: Retrieves a subportion from a string. (sub-string

) STR-INDEX: Returns the position of the first argument within the second argument. (str-index

) EVAL: Evaluates a string as though it were entered at the command prompt. Only allows functions to be evaluated. (eval ) BUILD: Evaluates a string as though it were entered at the command prompt. Only allows constructs to be evaluated. (build ) UPCASE: Converts lowercase characters in a string or symbol to uppercase. (upcase ) LOWCASE: Converts uppercase characters in a string or symbol to lowercase. (lowcase ) STR-COMPARE: Lexigraphically compares two strings. (str-compare

) STR-LENGTH: Returns the length of a string. (str-length ) CHECK-SYNTAX: Allows the text representation of a construct or function call to be checked for syntax and semantic errors. (check-syntax ) STRING-TO-FIELD: Parses a string and converts its contents to a primitive data type. (string-to-field ) END-ENTRY 2IBEGIN-ENTRY-IO_FUNCTIONS FUNCTION_SUMMARY IO_FUNCTIONS The following functions perform I/O operations. OPEN: Opens a file. (open

[]) ::= "r" | "w" | "r+" | "a" | "wb" CLOSE: Closes a file. (close []) PRINTOUT: Sends unformated output to the specified logical name. (printout *) READ: Reads a single-field value from the specified logical name. (read []) READLINE: Reads an entire line as a string from the specified logical name. (readline []) FORMAT: Sends formated output to the specified logical name. (format

*) RENAME: Changes the name of a file. (rename

) REMOVE: Deletes a file. (remove ) END-ENTRY 2MBEGIN-ENTRY-MATH_FUNCTIONS FUNCTION_SUMMARY MATH_FUNCTIONS The math functions have been divided into three broad categories. The basic math functions are always provided with CLIPS. The trigonometric and extended math functions are included as part of the extended math package. Subtopics: BASIC_MATH_FUNCTIONS EXTENDED_MATH_FUNCTIONS TRIGONOMETRIC_FUNCTIONS END-ENTRY 3IBEGIN-ENTRY-BASIC_MATH_FUNCTIONS FUNCTION_SUMMARY MATH_FUNCTIONS BASIC_MATH_FUNCTIONS The following functions perform basic mathematical operations. +: Returns the sum of its arguments. (+

+) -: Returns the first argument minus all subsequent arguments. (-

+) *: Returns the product of its arguments. (*

+) /: Returns the first argument divided by all subsequent arguments. (/

+) DIV: Returns the first argument divided by all subsequent arguments using integer division. (div

+) MAX: Returns the value of its largest numeric argument. (max +) MIN: Returns the value of its smallest numeric argument. (min +) ABS: Returns the absolute value of its only argument. (abs ) FLOAT: Converts its only argument to a float. (float ) INTEGER: Converts its only argument to an integer. (integer ) END-ENTRY 3IBEGIN-ENTRY-TRIGONOMETRIC_FUNCTIONS FUNCTION_SUMMARY MATH_FUNCTIONS TRIGONOMETRIC_FUNCTIONS The following trigonometric functions take one numeric argument and return a float. The argument is expected to be in radians. These functions are part of the extended math package. FUNCTION RETURNS ---------------------------------------- acos arccosine acosh hyperbolic arccosine acot arccotangent acoth hyperbolic arccotangent acsc arccosecant acsch hyperbolic arccosecant asec arcsecant asech hyperbolic arcsecant asin arcsine asinh hyperbolic arcsine atan arctangent atanh hyperbolic arctangent cos cosine cosh hyperbolic cosine cot cotangent coth hyperbolic tangent csc cosecant csch hyperbolic cosecant sec secant sech hyperbolic secant sin sine sinh hyperbolic sine tan tangent tanh hyperbolic tangent END-ENTRY 3IBEGIN-ENTRY-EXTENDED_MATH_FUNCTIONS FUNCTION_SUMMARY MATH_FUNCTIONS EXTENDED_MATH_FUNCTIONS The following functions perform extended mathematical operations and are included as part of the extended math package. DEG-GRAD: Converts its only argument from degrees to gradients. (deg-grad ) DEG-RAD: Converts its only argument from degrees to radians. (deg-rad ) GRAD-DEG: Converts its only argument from gradients to degrees. (grad-deg ) RAD-DEG: Converts its only argument from radians to degrees. (rad-deg ) PI: Returns the value of pi. (pi) SQRT: Returns the square root of its only argument. (sqrt ) **: Raises its first argument to the power of its second argument. (**

) EXP: Raises the value e to the power of its only argument. (exp ) LOG: Returns the logarithm base e of its only argument. (log ) LOG10: Returns the logarithm base 10 of its only argument. (log10 ) ROUND: Rounds its argument toward the closest integer or negative infinity if exactly between two integers. (round ) MOD: Returns the remainder of the result of dividing its first argument by its second argument (assuming that the result of division must be an integer). (mod

) END-ENTRY 2IBEGIN-ENTRY-PROCEDURAL_FUNCTIONS FUNCTION_SUMMARY PROCEDURAL_FUNCTIONS The following are functions which provide procedural programming capabilities as found in languages such as Pascal, C, and Ada. BIND: Binds a variable to a new value. (bind *) IF: Allows conditional execution of a group of actions. (if then * [else *]) WHILE: Allows conditional looping. (while [do] *) LOOP-FOR-COUNT: Allows simple iterative looping. (loop-for-count [do] *)