Intelligent Problem Solvers in Education: Design Method and Applications - Intelligent Systems - page 130

- A set of characters: letter, number, special letter.

-

Vocabulary: keywords, names.

- Data types: basic types and structured types.

- Expressions and sentences.

- Statements.

- Syntax for specifying the components of COKB model.

The followings are some structures of definitions for expressions, Com-Objects, relations,
facts, and functions.

Definitions of expressions:

expr ::= expr | rel-expr | logic-expr

expr ::= expr add-operator term | term

term ::= term mul-operator factor | factor

factor ::= - factor | element ^ factor | element

element ::= ( expr ) | name | number | function-call

rel-expr ::= expr rel-operator expr

logic-expr ::= logic-expr OR logic-term | logic-expr IMPLIES logic-term |

NOT logic-term |logic-term

logic-term ::= logic-term AND logic-primary |logic-primary

logic-primary ::= expr | rel-expr |function-call | quantify-expr | TRUE | FALSE

quantify-expr ::= FORALL( name <, name>* ), logic-expr | EXISTS( name ), logic-

expr

Definitions of Com-object type:

cobject-type ::= COBJECT name;

[isa]

[hasa]

[constructs]

[attributes]

[constraints]

[crelations]

[facts]

[rules]

ENDCOBJECT;

Definitions of computational relations:

crelations ::= CRELATION:

crelation-def+

ENDCRELATION;

crelation-def ::= CR name;

MF : name <, name>*;

MFEXP : equation;

ENDCR;

equation ::= expr = expr