Entity

To recall the concepts defined in the Concepts definition, you have to use the ENTITY element.

ENTITY is defined as:

ENTITY -> NAME LABEL? ATTRIBUTES?

where NAME is a string, LABEL is a temporary name which, inside a statement, can be used to refer to that entity, and ATTRIBUTES is a comma-separated list of ATTRIBUTE. ATTRIBUTE is defined as follows:

ATTRIBUTE -> "with" ATTRIBUTE_NAME VALUE? ATTRIBUTE_COMPARISON? ("," ATTRIBUTE)?

the “with” keyword is used to access the attributes of the entity, ATTRIBUTE_NAME is a string that should recall an attribute defined for that entity, and VALUE, optional, is an uppercase string or a math operation with the meaning of giving a value to that attribute. ATTRIBUTE_COMPARISON allows you to compare the attribute with other attributes values or constants and it is defined as follows:

ATTRIBUTE_COMPARISON -> COMPARISON_OPERATOR (MATH_EXPRESSION | STRING)
COMPARISON_OPERATOR -> "the same as" | "different from" | "equal to" | "more than" | "greater than" | "less than" | "greater than or equal to" | "less than or equal to" | "at least" | "at most" | "not after" | "between"

therefore, an ATTRIBUTE_COMPARISON is made of an operator (one of the listed above) and a STRING, i.e. a string value or a constant, or a MATH_EXPRESSION.

Examples:

(1) a movie M
(2) a movie with id MOVIEID
(3) a movie with id MOVIEID, with duration 100
(4) a movie with id MOVIEID+1
(5) a movie with id MOVIEID greater than X
(6) a movie with id MOVIEID greater than mycostant

Corresponding ASP:

Considering the following definition:

A movie is identified by an id, and has a duration.

The previous sentences are translated into:

(1) movie(M,_)
(2) movie(MOVIEID,_)
(3) movie(MOVIEID,100)
(4) movie(MOVIEID+1,_)
(5) movie(MOVIDEID,_), MOVIDEID > X
(6) movie(MOVIDEID,_), MOVIDEID > mycostant

In the first sentence, M is defined as the label of the entity movie. However, in case the entity has just one key or is defined by just one attribute, the tool sets that key (or the single attribute) equal to the value of the label.