Using the Help Facility from within the CLIPS dialog window.
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 [<path>])
where <path> 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.
<nil> 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 [<help-file-name>])
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.
The release notes help section contains information about new features
and where to get technical support.
Subtopics:
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, refer to appendix B of the Basic Programming Guide and appendix C of the Advanced Programming Guide.
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 Reply:, Reply to:, or From: 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.
This section gives a general overview of the available CLIPS constructs.
Subtopics:
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 <rule-name> [<comment>] [<declaration>] <conditional-element>* => <action>*)
DECLARATIONS
<declaration> ::= (declare <rule-property>+) <rule-property> ::= (salience <integer-expression>) | (auto-focus <boolean-symbol>)
CONDITIONAL ELEMENTS
<conditional-element> ::= <pattern-CE> | <assigned-pattern-CE> | <not-CE> | <and-CE> | <or-CE> | <logical-CE> | <test-CE> | <exists-CE> | <forall-CE> <test-CE> ::= (test <function-call>) <not-CE> ::= (not <conditional-element>) <and-CE> ::= (and <conditional-element>+) <or-CE> ::= (or <conditional-element>+) <exists-CE> ::= (exists <conditional-element>+) <forall-CE> ::= (forall <conditional-element> <conditional-element>+) <logical-CE> ::= (logical <conditional-element>+)
PATTERN CONDITIONAL ELEMENT
<assigned-pattern-CE>::= ?<variable-symbol> <- <pattern-CE> <pattern-CE> ::= <ordered-pattern-CE> | <template-pattern-CE> | <object-pattern-CE> <ordered-pattern-CE> ::= (<symbol> <constraint>*) <template-pattern-CE>::= (<deftemplate-name <LHS-slot>*) <object-pattern-CE> ::= (object <attribute-constraint>*) <attribute-constraint> ::= (is-a <constraint>) | (name <constraint>) | (<slot-name> <constraint>*) <LHS-slot> ::= <single-field-LHS-slot> | <multifield-LHS-slot> <LHS-slot> ::= <single-field-LHS-slot> | <multifield-LHS-slot> <single-field-LHS-slot> ::= (<slot-name> <constraint>) <multifield-LHS-slot> ::= (<slot-name> <constraint>*)
PATTERN CONSTRAINTS
<constraint> ::= ? | $? | <connected-constraint> <connected-constraint> ::= <single-constraint> | <single-constraint> & <connected-constraint> | <single-constraint> | <connected-constraint> <single-constraint> ::= <term> | ~<term> <term> ::= <constant> | <single-field-variable> | <multifield-variable> | :<function-call> | =<function-call>
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 <deffacts-name> [<comment>] <RHS-pattern>*)
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 <deftemplate-name> [<comment>] <slot-definition>*) <slot-definition> ::= <single-slot-definition> | <multislot-definition> <single-slot-definition> ::= (slot <slot-name> <template-attribute>*) <multislot-definition> ::= (multislot <slot-name> <template-attribute>*) <template-attribute> ::= <default-attribute> | <constraint-attribute> <default-attribute> ::= (default ?DERIVE | ?NONE | <expression>*) | (default-dynamic <expression>*)
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-construct> ::= (defglobal [<defmodule-name>] <global-assignment>*) <global-assignment> ::= <global-variable> = <expression> <global-variable> ::= ?*<symbol>*
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 <name> [<comment>] (<regular-parameter>* [<wildcard-parameter>]) <action>*) <regular-parameter> ::= <single-field-variable> <wildcard-parameter> ::= <multifield-variable>
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 <name> [<comment>]) (defmethod <name> [<index>] [<comment>] (<parameter-restriction>* [<wildcard-parameter>]) <action>*) <parameter-restriction> ::= <single-field-variable> | (<single-field-variable> <type>* [<query>]) <wildcard-parameter> ::= <multifield-variable> <type> ::= <class-name> <query> ::= <global-variable> | <function-call>
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 <name> [<comment>] (is-a <superclass-name>+) [<role>] [<pattern-match-role>] <slot>* <handler-documentation>*) <role> ::= (role concrete | abstract) <pattern-match-role> ::= (pattern-match reactive | non-reactive) <slot> ::= (slot <name> <facet>*) | (single-slot <name> <facet>*) | (multislot <name> <facet>*) <facet> ::= <default-facet> | <storage-facet> | <access-facet> | <propagation-facet> | <source-facet> | <pattern-match-facet> | <visibility-facet> | <create-accessor-facet> <override-message-facet> | <constraint-attributes> <default-facet> ::= (default ?DERIVE | ?NONE | <expression>*) | (default-dynamic <expression>*) <storage-facet> ::= (storage local | shared) <access-facet> ::= (access read-write | read-only | initialize-only) <propagation-facet> ::= (propagation inherit | no-inherit) <source-facet> ::= (source exclusive | composite) <pattern-match-facet> ::= (pattern-match reactive | non-reactive) <visibility-facet> ::= (visibility private | public) <create-accessor-facet> ::= (create-accessor ?NONE | read | write | read-write) <override-message-facet> ::= (override-message ?DEFAULT | <message-name>) <handler-documentation> ::= (message-handler <name> [<handler-type>]) <handler-type> ::= primary | around | before | after
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-construct> ::= (definstances <definstances-name> [<comment>] <instance-template>*) <instance-template> ::= (<instance-definition>) <instance-definition> ::= <instance-name-expression> of <class-name-expression> <slot-override>* <slot-override> ::= (<slot-name-expression> <expression>*)
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 <class-name> <message-name> [<handlertype>] [<comment>] (<parameter>* [<wildcard-parameter>]) <action>*) <handler-type> ::= around | before | primary | after <parameter> ::= <single-field-variable> <wildcard-parameter> ::= <multifield-variable>
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-construct> ::= (defmodule <module-name> [<comment>] <port-spec>*) <port-specification> ::= (export <port-item>) | (import <module-name> <port-item>) <port-item> ::= ?ALL | ?NONE | <port-construct> ?ALL | <port-construct> ?NONE | <port-construct> <construct-name>+ <port-construct> ::= deftemplate | defclass | defglobal | deffunction | defgeneric
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:
<constraint-attribute> ::= <type-attribute> | <allowed-constant-attribute> | <range-attribute> | <cardinality-attribute> <default-attribute> <type-attribute> ::= (type <type-specification>) <type-specification> ::= <allowed-type>+ | ?VARIABLE <allowed-type> ::= SYMBOL | STRING | LEXEME | INTEGER | FLOAT | NUMBER | INSTANCE-NAME | INSTANCE-ADDRESS | INSTANCE | EXTERNAL-ADDRESS | FACT-ADDRESS <allowed-constant-attribute> ::= (allowedsymbols <symbol-list>) | (allowedstrings <string-list>) | (allowed-lexemes <lexeme-list> | (allowedintegers <integer-list>) | (allowedfloats <float-list>) | (allowednumbers <number-list>) | (allowed-instance-names <instance-list>) | (allowedvalues <value-list>) | <symbol-list> ::= <symbol>+ | ?VARIABLE <string-list> ::= <string>+ | ?VARIABLE <lexeme-list> ::= <lexeme>+ | ?VARIABLE <integer-list> ::= <integer>+ | ?VARIABLE <float-list> ::= <float>+ | ?VARIABLE <number-list> ::= <number>+ | ?VARIABLE <instance-name-list> ::= <instance-name>+ | ?VARIABLE <value-list> ::= <constant>+ | ?VARIABLE <range-attribute> ::= (range <range-specification> <range-specification>) <range-specification> ::= <number> | ?VARIABLE <cardinality-attribute> ::= (cardinality <cardinality-specification> <cardinality-specification>) <cardinality-specification> ::= <integer> | ?VARIABLE
This section gives a general overview of the available CLIPS functions.
Subtopics:
The following functions perform predicate tests and return either TRUE or FALSE.
FLOATPFLOATP
Returns TRUE for integers and floats.
(numberp <expression>)
Returns TRUE for floats.
(floatp <expression>)
Returns TRUE for integers.
(integerp <expression>)
Returns TRUE for symbols and strings.
(numberp <expression>)
Returns TRUE for strings.
(stringp <expression>)
Returns TRUE for symbols.
(symbolp <expression>)
Returns TRUE for even numbers.
(evenp <expression>)
Returns TRUE for odd numbers.
(oddp <expression>)
Returns TRUE for multifield values.
(multifieldp <expression>)
Returns TRUE for external addresses.
(pointerp <expression>)
Returns TRUE if the 1st argument is equal in type and value to all subsequent arguments.
(eq <expression> <expression>+)
Returns TRUE if the 1st argument is not equal in type and value to all subsequent arguments.
(neq <expression> <expression>+)
Returns TRUE if the 1st argument is equal in value to all subsequent arguments.
(= <numeric-expression> <numeric-expression>+)
Returns TRUE if the 1st argument is not equal in value to all subsequent arguments.
(<> <numeric-expression> <numeric-expression>+)
Returns TRUE if each argument is greater in value than the argument following it.
(> <numeric-expression> <numeric-expression>+)
Returns TRUE if each argument is greater than or equal to in value than the argument following it.
(>= <numeric-expression> <numeric-expression>+)
Returns TRUE if each argument is less in value than the argument following it.
(> <numeric-expression> <numeric-expression>+)
Returns TRUE if each argument is less than or equal to in value than the argument following it.
(<= <numeric-expression> <numeric-expression>+)
Returns TRUE if all arguments evaluate to a non-FALSE value.
(and <expression>+)
Returns TRUE if any argument evaluates to a non-FALSE value.
(or <expression>+)
Returns TRUE if its only argument evaluates to FALSE.
(not <expression>)
The following functions operate on multifield values.
Appends its arguments together to create a multifield value.
(create$ <expression>*)
Returns the specified field of a multifield value.
(nth$ <integer-expression> <multifield-expression>)
Returns the position of a single-field value within a multifield value.
(member$ <single-field-expression> <multifield-expression>)
Returns TRUE if the first argument is a subset of the second argument.
(subsetp <multifield-expression> <multifield-expression>)
Deletes the specified range from a multifield value.
(delete$ <multifield-expression> <begin-integer-expression> <end-integer-expression>)
Deletes specific values contained within a multifield value and returns the modified multifield value.
(delete-member$ <multifield-expression> <expression>+)
Creates a multifield value from a string.
(explode$ <string-expression>)
Creates a string from a multifield value.
(implode$ <multifield-expression>)
Extracts the specified range from a multifield value.
(subseq$ <multifield-expression> <begin-integer-expression> <end-integer-expression>)
Replaces the specified range of a multifield value with a set of values.
(replace$ <multifield-expression> <begin-integer-expression> <end-integer-expression> <single-or-multifield-expression>+)
Replaces specific values contained within a multifield value and returns the modified multifield value.
(replace-member$ <multifield-expression> <substitute-expression> <search-expression>+)
Inserts one or more values in a multifield.
(insert$ <multifield-expression> <integer-expression> <single-or-multifield-expression>+)
Returns the first field of a multifield.
(first$ <multifield-expression>)
Returns all but the first field of a multifield.
(rest$ <multifield-expression>)
Returns the number of fields in a multifield value.
(length$ <multifield-expression>)
The following functions perform operations that are related to strings.
Concatenates its arguments to form a single string.
(str-cat <expression>*)
Concatenates its arguments to form a single symbol.
(sym-cat <expression>*)
Retrieves a subportion from a string.
(sub-string <integer-expression> <integer-expression> <string-expression>)
Returns the position of the first argument within the second argument.
(str-index <lexeme-expression> <lexeme-expression>)
Evaluates a string as though it were entered at the command prompt. Only allows functions to be evaluated.
(eval <lexeme-expression>)
Evaluates a string as though it were entered at the command prompt.
Only allows constructs to be evaluated.
(build <lexeme-expression>)
Converts lowercase characters in a string or symbol to uppercase.
(upcase <lexeme-expression>)
Converts uppercase characters in a string or symbol to lowercase.
(lowcase <lexeme-expression>)
Lexigraphically compares two strings.
(str-compare <lexeme-expression> <lexeme-expression>)
Returns the length of a string.
(str-length <lexeme-expression>)
Allows the text representation of a construct or function call to be checked for syntax and semantic errors.
(check-syntax <construct-or-function-string>)
Parses a string and converts its contents to a primitive data type.
(string-to-field <string-or-symbol-expression>)
The following functions perform I/O operations.
Opens a file.
(open <file-name> <logical-name> [<mode>]) <mode> ::= "r" | "w" | "r+" | "a" | "wb"
Closes a file.
(close [<logical-name>])
Sends unformated output to the specified logical name.
(printout <logical-name> <expresion>*)
Reads a single-field value from the specified logical name.
(read [<logical-name>])
Reads an entire line as a string from the specified logical name.
(readline [<logical-name>])
Sends formated output to the specified logical name.
(format <logical-name> <string-expression> <expression>*)
Changes the name of a file.
(rename <old-file-name> <new-file-name>)
Deletes a file.
(remove <file-name>)
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:
The following functions perform basic mathematical operations.
Returns the sum of its arguments.
(+ <numeric-expression> <numeric-expression>+)
Returns the first argument minus all subsequent arguments.
(- <numeric-expression> <numeric-expression>+)
Returns the product of its arguments.
(* <numeric-expression> <numeric-expression>+)
Returns the first argument divided by all subsequent arguments.
(/ <numeric-expression> <numeric-expression>+)
Returns the first argument divided by all subsequent arguments using integer division.
(div <numeric-expression> <numeric-expression>+)
Returns the value of its largest numeric argument.
(max <numeric-expression>+)
Returns the value of its smallest numeric argument.
(min <numeric-expression>+)
Returns the absolute value of its only argument.
(abs <numeric-expression>)
Converts its only argument to a float.
(float <numeric-expression>)
Converts its only argument to an integer.
(integer <numeric-expression>)
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.
FUNCTIONRETURNS
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
The following functions perform extended mathematical operations and are included as part of the extended math package.
Converts its only argument from degrees to gradients.
(deg-grad <numeric-expression>)
Converts its only argument from degrees to radians.
(deg-rad <numeric-expression>)
Converts its only argument from gradients to degrees.
(grad-deg <numeric-expression>)
Converts its only argument from radians to degrees.
(rad-deg <numeric-expression>)
Returns the value of pi.
(pi)
Returns the square root of its only argument.
(sqrt <numeric-expression>)
Raises its first argument to the power of its second argument.
(** <numeric-expression> <numeric-expression>)
Raises the value e to the power of its only argument.
(exp <numeric-expression>)
Returns the logarithm base e of its only argument.
(log <numeric-expression>)
Returns the logarithm base 10 of its only argument.
(log10 <numeric-expression>)
Rounds its argument toward the closest integer or negative infinity if exactly between two integers.
(round <numeric-expression>)
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 <numeric-expression> <numeric-expression>)
The following are functions which provide procedural programming capabilities as found in languages such as Pascal, C, and Ada.
Binds a variable to a new value.
(bind <variable> <expression>*)
Allows conditional execution of a group of actions.
(if <expression> then <action>* [else <action>*])
Allows conditional looping.
(while <expression> [do] <action>*)
Allows simple iterative looping.
(loop-for-count <range-spec> [do] <action>*) <range-spec> ::= <end-index> | (<loop-variable> [<start-index> <end-index>]) <start-index> ::= <integer-expression> <end-index> ::= <integer-expression>
Evaluates all arguments and returns the value of the last argument evaluated.
(progn <expression>*)
Performs a set of actions for each field of a multifield value.
(progn$ <list-spec> <expression>*) <list-spec> ::= <multifield-expression> | (<list-variable> <multifield-expression>)
Immediately terminates the currently executing deffunction, generic function method, message-handler, defrule RHS, or certain instance set query functions and if a value is specified, returns this value as the result of the executing construct.
(return [<expression>])
Immediately terminates the currently iterating while loop, progn execution, or certain instance set query functions.
(break)
Allows a particular group of actions to be performed based on a specified value.
(switch <test-expression> <case-statement>* [<default-statement>]) <case-statement> ::= (case <comparison-expression> then <action>*) <default-statement> ::= (default <action>*)
The following are additional functions for use within CLIPS.
Returns a special sequenced symbol.
(gensym)
Returns a special unique sequenced symbol.
(gensym*)
Sets the starting number used by gensym and gensym*.
(setgen <integer-expression>)
Returns a “random” integer value.
(random [<start-integer-expression> <end-integer-expression>])
Seeds the random number generator used by random.
(seed <integer-expression>)
Returns a float representing the elapsed seconds since the system reference time.
(time)
Returns an integer for the number of fields in a multifield value or the length in characters of a string or symbol.
(length <lexeme-or-multifield-expression>)
Returns the restriction string associated with a CLIPS or user defined function.
(get-function-restrictions <function-name>)
Allows a list of values to be sorted based on a user specified comparison function.
(sort <comparison-function-name> <expression>*)
Constructs a function call from its arguments and then evaluates the function call.
(funcall (function-name> <expression>*)
Returns the number of seconds elapsed evaluating a series of expressions.
(timer <expression>*)
The following functions provide ancillary capabilities for the deftemplate construct.
Returns the list of all deftemplates in the specified module (or the current module if unspecified).
(get-deftemplate-list [<module-name>])
Returns the module in which the specified deftemplate is defined.
(deftemplate-module <deftemplate-name>)
The following actions are used for assert, retracting, and modifying facts.
Adds a fact to the fact-list.
(assert <RHS pattern>+)
Removes a fact from the fact-list.
(retract <retract-specifier>+ | *) <retract-specifier> ::= <fact-specifier> | <integer-expression>
Modifies a deftemplate fact in the fact-list.
(modify <fact-specifier> <RHS-slot>*)
Duplicates a deftemplate fact in the fact-list.
(duplicate <fact-specifier> <RHS-slot>*)
Converts a string into a fact and asserts it.
(assert-string <string-expression>)
Returns the fact index of a fact address.
(fact-index <fact-address>)
Returns TRUE if the fact specified by its fact-index or fact-address argument exists, otherwise FALSE.
(fact-existp <fact-address-or-index>)
Returns the deftemplate (relation) name associated the fact.
(fact-relation <fact-address-or-index>)
Returns the slot names associated with the fact.
(fact-slot-names <fact-address-or-index>)
Returns the value of the specified slot from the specified fact.
(fact-slot-value <fact-address-or-index> <slot-name>)
Returns a multifield containing the list of visible facts.
(get-fact-list [<module-name>])
The following functions provide ancillary capabilities for the deffacts construct.
Returns the list of all deffacts in the specified module (or the current module if unspecified).
(get-deffacts-list [<module-name>])
Returns the module in which the specified deffacts is defined.
(deffacts-module <deffacts-name>)
The following functions provide ancillary capabilities for the defrule construct.
Returns the list of all defrules in the specified module (or the current module if unspecified).
(get-defrule-list [<module-name>])
Returns the module in which the specified defrule is defined.
(defrule-module <defrule-name>)
The following functions provide ancillary capabilities for manipulating the agenda.
Returns the module name of the current focus.
(get-focus)
Returns all of the module names in the focus stack as a multifield value.
(get-focus-stack)
Removes the current focus from the focus stack and returns the module name of the current focus.
(pop-focus)
The following functions provide ancillary capabilities for the defglobal construct.
Returns the list of all defglobals in the specified module (or the current module if unspecified).
(get-defglobal-list [<module-name>])
Returns the module in which the specified defglobal is defined.
(defglobal-module <defglobal-name>)
The following functions provide ancillary capabilities for the deffunction construct.
Returns the list of all deffunctions in the specified module (or the current module if unspecified).
(get-deffunction-list [<module-name>])
Returns the module in which the specified deffunction is defined.
(deffunction-module <deffunction-name>)
The following functions provide ancillary capabilities for generic function methods.
Returns the list of all defgenerics in the specified module (or the current module if unspecified).
(get-defgeneric-list [<module-name>])
Returns the module in which the specified defgeneric is defined.
(defgeneric-module <defgeneric-name>)
Returns the list of all defmethods in the current module (or just the methods associated with the specified defgeneric).
(get-defmethod-list [<defgeneric-name>])
Returns a symbol which is the name of the type (or class) of its of argument.
(type <expression>)
If called from a method for a generic function, the function next-methodp will return the symbol TRUE if there is another method shadowed by the current one. Otherwise, the function will return the symbol FALSE.
(next-methodp)
Calls the next shadowed method.
(call-next-method)
Calls the next shadowed method allowing new arguments to be provided.
(override-next-method <expression>*)
Calls a particular method of a generic function without regards to method precedence.
(call-specific-method <generic-function> <method-index> <expression>*)
Returns a multifield value containing information about the restrictions for the specified method.
(get-method-restrictions <generic-function-name> <method-index>)
The functions manipulating the CLIPS Object-Oriented Language (COOL) are divided into five categories.
Subtopics:
The following functions are used with classes.
Returns the list of all defclasses in the specified module (or the current module if unspecified).
(get-defclass-list [<module-name>])
Returns the module in which the specified defclass is defined.
(defclass-module <defclass-name>)
Returns TRUE if the specified class is defined, FALSE otherwise.
(class-existp <class-name>)
Returns TRUE if the first class is a superclass of the second class, FALSE otherwise.
(superclassp <class1-name> <class2-name>)
Returns TRUE if the first class is a subclass of the second class, FALSE otherwise.
(subclassp <class1-name> <class2-name>)
Returns TRUE if the specified slot is present in the class, FALSE otherwise. If the inherit keyword is specified, then the slot may be inherited.
(slot-existp <class-name> <slot-name> [inherit])
Returns TRUE if the specified slot is writable, otherwise FALSE.
(slot-writablep <class-name> <slot-name>)
Returns TRUE if the specified slot is initializable, otherwise FALSE.
(slot-initablep <class-name> <slot-name>)
Returns TRUE if the specified slot is public, otherwise FALSE.
(slot-initablep <class-name> <slot-name>)
Returns TRUE if the specified slot can be accessed directly, otherwise FALSE.
(slot-direct-accessp <class-name> <slot-name>)
Returns TRUE if the specified message-handler is defined (directly, not by inheritance) for the class, FALSE otherwise.
(message-handler-existp <class-name> <handler-name> [<handler-type>]) <handler-type> ::= around | before | primary | after
Returns TRUE if the specified class is abstract, FALSE otherwise.
(class-abstractp <class-name>)
Returns TRUE if the specified class is reactive, FALSE otherwise.
(class-reactivep <class-name>)
Returns the names of the direct superclasses of a class in a multifield variable. If the optional “inherit” argument is given, indirect superclasses are also included.
(class-superclasses <class-name> [inherit])
Returns the names of the direct subclasses of a class in a multifield variable. If the optional “inherit” argument is given, indirect subclasses are also included.
(class-subclasses <class-name> [inherit])
Returns the names of the explicitly defined slots of a class in a multifield variable. If the optional inherit keyword is given, inherited slots are also included.
(class-slots <class-name> [inherit])
Returns the class names, message names, and message types of the message-handlers directly attached to a class in a multifield variable. If the optional inherit keyword is given, inherited message-handlers are also included.
(get-defmessage-handler-list <class-name> [inherit])
Returns the facet values for the specified slot of a class in a multifield value.
(slot-facets <class-name> <slot-name>)
Returns the names of the classes which provide facets for a slot of a class in a multifield variable.
(slot-sources <class-name> <slot-name>)
Returns the names of the primitive types allowed for a slot in a multifield variable.
(slot-types <class-name> <slot-name>)
Returns the minimum and maximum number of fields allowed for a multislot in a multifield variable.
(slot-cardinality <class-name> <slot-name>)
Returns the allowed values for a slot in a multifield value.
(slot-allowed-values <class-name> <slot-name>)
Returns the minimum and maximum numeric values allowed for a slot.
(slot-range <class-name> <slot-name>)
Returns the default value associated with a slot.
(slot-default-value <class-name> <slot-name>)
Returns the current defaults mode used when classes are defined.
(get-class-defaults-mode)
Sets the defaults mode used when classes are defined.
(set-class-defaults-mode <mode>) <mode> ::= convenience | conservation
The following functions are used with message-handlers.
Returns TRUE if there is another message-handler available for execution, FALSE otherwise.
(next-handlerp)
Calls the next shadowed handler.
(call-next-handler)
Calls the next shadowed handler and allows the arguments to be changed.
(override-next-handler <expression>*)
Returns the list of all definstances in the specified module (or the current module if unspecified).
(get-definstances-list [<module-name>])
Returns the module in which the specified definstance is defined.
(definstances-module <definstances-name>)
The following manipulation functions are used with instances.
Implements the init message-handler attached to the class USER. This function should never be called directly unless an init message-handler is being defined such that the one attached to USER will never be called.
(init-slots)
Deletes the specified instance by sending it the delete message.
(unmake-instance <instance-expression> | *)
Deletes the active instance when called from within the body of a message-handler.
(delete-instance)
Returns a symbol which is the name of the class of its argument.
(class <object-expression>)
Returns a symbol which is the name of its instance argument.
(instance-name <instance-expression>)
Returns the address of its instance argument.
(instance-address <instance-expression>)
Converts a symbol to an instance name.
(symbol-to-instance-name <symbol-expression>)
Converts an instance name to a symbol.
(instance-name-to-symbol <instance-name-expression>)
The following predicate functions are used with instances.
Returns TRUE if its argument is an instance name or instance address, FALSE otherwise.
(instancep <expression>)
Returns TRUE if its argument is an instance address, FALSE otherwise.
(instance-addressp <expression>)
Returns TRUE if its argument is an instance name, FALSE otherwise.
(instance-namep <expression>)
Returns TRUE if the specified instance exists, FALSE otherwise.
(instance-existp <instance-expression>)
The following functions are used to manipulate instance slots.
Returns the value of the specified slot of the active instance.
(dynamic-get <slot-name-expression>)
Sets the value of the specified slot of the active instance.
(put <slot-name-expression> <expression>*)
Allows the replacement of a range of fields in a multifield slot value.
(slot-replaceR <instance-expression> <mv-slot-name> <range-begin> <range-end> <expression>+)
Allows the replacement of a range of fields in a multifield slot value of the active instance from within a message-handler.
(direct-slot-replace$ <mv-slot-name> <range-begin> <range-end> <expression>+)
Allows the insertion of one or more values in a multifield slot value.
(slot-insert$ <instance-expression> <mv-slot-name> <index> <expression>+)
Allows the insertion of one or more values in a multifield slot value of the active instance from within a message-handler.
(direct-slot-insert$ <mv-slot-name> <index> <expression>+)
Allows the deletion of a range of fields in a multifield slot value.
(slot-delete$ <instance-expression> <mv-slot-name> <range-begin> <range-end>)
Allows the deletion of a range of fields in a multifield slot value of the active instance from within a message-handler.
(direct-slot-delete$ <mv-slot-name> <range-begin> <range-end>)
The following functions provide ancillary capabilities for the defmodule construct.
Returns the list of all defmodules.
(get-defmodule-list)
The following functions provide ancillary capabilities for the sequence expansion operator.
When used inside of a function call, expands its arguments as separate arguements to the function. The $ operator is merely a shorthand notation for the expand$ function call.
(expand$ <multifield-expression>)
Sets the sequence operator recognition behavior.
(setsequence-operator-recognition <boolean-expression>)
Returns the current value of the sequence operator recognition behavior.
(getsequence-operator-recognition)
This section gives a general overview of the available CLIPS commands.
Subtopics:
The following commands control the CLIPS environment.
BATCH*
GET-DYNAMIC-CONSTRAINT-CHECKING
GET-STATIC-CONSTRAINT-CHECKING
LOAD*
SET-DYNAMIC-CONSTRAINT-CHECKING
Loads constructs from a file.
(load <file-name>)
Loads constructs from a file without displaying messages.
(load* <file-name>)
Saves constructs to a file.
(save <file-name>)
Loads a binary image from a file.
(bload <file-name>)
Saves a binary image to a file.
(bsave <file-name>)
Clears the CLIPS environment.
(clear)
Exits the CLIPS environment.
(exit)
Resets the CLIPS environment.
(reset)
Executes commands from a file.
(batch <file-name>)
Executes commands from a file. Unlike the batch command, evaluates all of the commands in the specified file before returning rather than replacing standard input.
(batch* <file-name>)
Lists the settings of CLIPS compiler flags.
(options)
Appends its arguments together to form a command which is then sent to the operating system.
(system <lexeme-expression>*)
Sets the auto-float dividend behaviour.
(set-auto-float-dividend <boolean-expression>)
Returns the current value of the auto-float dividend behaviour.
(get-auto-float-dividend)
Sets the dynamic constraint checking behaviour.
(set-dynamic-constraint-checking <boolean-expression>)
Returns the current value of the dynamic constraint checking behaviour.
(get-dynamic-constraint-checking)
Sets the static constraint checking behaviour.
(set-static-constraint-checking <boolean-expression>)
Returns the current value of the static constraint checking behaviour.
(get-static-constraint-checking)
Displays all symbols currently defined in CLIPS which contain a specified substring.
(apropos <lexeme>)
The following commands control the CLIPS debugging features.
Sends trace information to the specified file.
(dribble-on <file-name>)
Closes the trace file.
(dribble-off)
Enables trace information for the specified item.
(watch <watch-item>) <watch-item> ::= all | compilations | statistics | focus | messages | deffunctions <deffunction-name>* | globals <global-name>* | rules <rule-name>* | activations <rule-name>* | facts <deftemplate-name>* | instances <class-name>* | slots <class-name>* | message-handlers <handler-spec-1>* [<handler-spec-2>]) | generic-functions <generic-name>* | methods <method-spec-1>* [<method-spec-2>] <handler-spec-1> ::= <class-name> <handler-name> <handler-type> <handler-spec-2> ::= <class-name> [<handler-name> [<handler-type>]] <method-spec-1> ::= <generic-name> <method-index> <method-spec-2> ::= <generic-name> [<method-index>]
Disables trace information for the specified item.
(unwatch <watch-item>)
Displays the current state of watch items.
(list-watch-items [<watch-item>])
Displays the text of a given deftemplate.
(ppdeftemplate <deftemplate-name>)
Displays the list of all deftemplates in the specified module (or the current module if none specified).
(list-deftemplates [<module-name>])
Deletes a deftemplate.
(undeftemplate <deftemplate-name>)
The following commands display information about facts.
Display the facts in the fact-list.
(facts [<module-name>] [<start-integer-expression> [<end-integer-expression> [<max-integer-expression>]]])
Asserts facts loaded from a file.
(load-facts <file-name>)
Saves facts to a file.
(save-facts <file-name> [<save-scope> <deftemplate-names>*]) <save-scope> ::= visible | local
Lists the partial matches from which a fact or instance receives logical support.
(dependencies <fact-or-instance-specifier>)
Lists all facts or instances which receive logical support from a fact or instance.
(dependents <fact-or-instance-specifier>)
Sets the fact duplication behavior.
(set-fact-duplication <boolean-expression>)
Returns the fact duplication behavior.
(get-fact-duplication)
Displays the text of a given deffacts.
(ppdeffacts <deffacts-name>)
Displays the list of all deffacts in the specified module (or the current module if none specified).
(list-deffacts [<module-name>])
Deletes a deffacts.
(undeffacts <deffacts-name>)
The following commands manipulate defrules.
Displays the text of a given rule.
(ppdefrule <rule-name>)
Displays the list of all defrules in the specified module (or the current module if none specified).
(list-defrules [<module-name>])
Deletes a defrule.
(undefrule <rule-name>)
Displays the facts which match the patterns of a rule.
(matches <rule-name>)
Sets a breakpoint on a rule.
(set-break <rule-name>)
Removes a breakpoint on a rule.
(remove-break [<rule-name>])
Displays all rules having breakpoints.
(show-breaks [<module-name>])
Places all current activations of a rule on the agenda.
(refresh <rule-name>)
Sets the incremental reset behavior.
(set-incremental-reset <boolean-expression>)
Returns the incremental reset behavior.
(get-incremental-reset)
The following commands manipulate the agenda.
Displays all activations on the agenda of the specified module.
(agenda [<module-name>])
Starts execution of rules. Rules fire until agenda is empty or the number of rule firings limit specified by the first argument is reached (infinity if unspecified).
(run [<integer-expression>])
Pushes one or more modules onto the focus stack.
(focus <module-name>+)
Stops rule execution.
(halt)
Sets the current conflict resolution strategy.
(set-strategy <strategy>) <strategy> ::= depth | breadth | simplicity | complexity | lex | mea | random
Returns the current conflict resolution strategy.
(get-strategy)
Lists all module names on the focus stack.
(list-focus-stack)
Removes all modules from the focus stack.
(clear-focus-stack)
Sets the salience evaluation behavior.
(set-salience-evaluation <behavior>) <behavior> ::= when-defined | when-activated | every-cycle
Returns the salience evaluation behavior.
(get-salience-evaluation)
Forces reevaluation of salience of rules on the agenda of the specified module.
(refresh-agenda [<module-name>])
The following commands manipulate defglobals.
Displays the text required to define a given global variable.
(ppdefglobal <global-variable-name>)
Displays the list of all defglobals in the specified module (or the current module if none specified).
(list-defglobals [<module-name>])
Deletes a global variable.
(undefglobal <global-variable-name>)
Displays the name and current value of all defglobals n the specified module (or the current module if none specified).
(show-defglobals [<module-name>])
Sets the reset global variables behavior.
(set-reset-globals <boolean-expression>)
Returns the reset global variables behavior.
(get-reset-globals)
Displays the text of a given deffunction.
(ppdeffunction <deffunction-name>)
Displays the list of all deffunctions in the specified module (or the current module if none specified).
(list-deffunctions [<deffunction-name>])
Deletes a deffunction.
(undeffunction <deffunction-name>)
The following commands manipulate generic functions.
Displays the text of a given generic function header.
(ppdefgeneric <generic-function-name>)
Displays the text of a given method.
(ppdefmethod <generic-function-name> <index>)
Displays the names of all generic functions in the specified module (or the current module if none specified).
(list-defgenerics [<module-name>])
Displays a list of generic function methods.
(list-defmethods [<generic-function-name>])
Deletes a generic function.
(undefgeneric <generic-function-name>)
Deletes a generic function method.
(undefmethod <generic-function-name> <index>)
Lists all applicable methods for a particular generic function call in order of decreasing precedence.
(preview-generic <generic-function-name> <expression>*)
The commands manipulating the CLIPS Object-Oriented Language (COOL)
are divided into four categories.
Subtopics:
The following commands manipulate defclasses.
Displays the text of a given defclass.
(ppdefclass <class-name>)
Displays the list of all defclasses in the specified module (or the current module if none specified).
(list-defclasses [<module-name>])
Deletes a defclass, all its subclasses, and all associated instances.
(undefclass <class-name>)
Provides a verbose description of a class.
(describe-class <class-name>)
Provides a rudimentary display of the inheritance relationships between a class and all its subclasses.
(browse-classes [<class-name>])
The following commands manipulate defmessage-handlers.
Displays the text of a given defmessage-handler.
(ppdefmessage-handler <class-name> <handler-name> [<handler-type>])
Displays a list of all (or some) defmessage-handlers.
(list-defmessage-handlers [<class-name> [<handler-name> [<handler-type>]]])
Deletes a defmessage-handler.
(undefmessage-handler <class-name> <handler-name> [<handler-type>])
Displays a list of all the applicable message-handlers for a message sent to an instance of a particular class.
(preview-send <class-name> <message-name>)
<handler-type> ::= around | before | primary | after
Displays the text of a given definstances.
(ppdefinstances <definstances-name>)
Displays the list of all definstances in the specified module (or the current module if none specified).
(list-definstances [<module-name>])
Deletes a definstances
(undefinstances <definstances-name>)
The following commands manipulate instances of user-defined classes.
Displays a list of instances.
(instances [<module-name> [<class-name> [inherit]]])
Prints the slots of the active instance when called from within the body of a message-handler.
(ppinstance)
Saves all instances to the specified file.
(save-instances <file-name>)
Loads instances from the specified file.
(load-instances <file-name>)
Loads instances from the specified file.
(restore-instances <file-name>)
The following commands manipulate defmodules.
Displays the text of a given defmodule.
(ppdefmodule <defmodule-name>)
Displays the list of all defmodules.
(list-defmodules)
Sets the current module.
(set-current-module <module-name>)
Returns the current module.
(get-current-module)
The following commands display CLIPS memory status information.
Returns number of bytes of memory CLIPS is using.
(mem-used)
Returns the number of times CLIPS has requested memory from the operating system.
(mem-requests)
Releases all free memory held internally by CLIPS to the operating system. Returns the amount of memory freed.
(release-mem)
Turns on or off the storage of information used for the save and pretty-print commands.
(conserve-mem <status>) <status> ::= on | off
The following commands can be used by users to maintain their own information system similar to the help facility.
Loads the named file into the internal lookup table.
(fetch <file-name>)
Looks up the specified entry in a particular file which has been previously loaded into the lookup table and prints the contents of that entry to the specified logical name.
(print-region <logical-name> <lookup-file> <topic-field>*)
Unloads the named file from the internal lookup table.
(toss <file-name>)
The following commands provide the ability to profile CLIPS programs
for performance..
Returns the current value of the profile percent threshold.
(get-profile-percent-threshold)
Enables/disables profiling of constructs and user functions.
(profile constructs | user-functions | off)
Displays profiling information currently collected for constructs or user functions.
(profile-info)
Resets all profiling information currently collected for constructs and user functions.
(profile-reset)
Sets the minimum percentage of time that must be spent executing a construct or user function for it to be displayed by the profile-info command.
(set-profile-percent-threshold <number in the range 0 to 100>)