[Harrison Pratt]

It is straightforward to refer to other predicates in predicate and fact declarations.

Is there a way to similarly directly refer to a database fact?

Code: Select all

class facts - menuDB
    menuAction : (string ActionName, predicate Action).
    namedProperty : (string PropertyName, fact Property). % <== can VP do something like this ?
 
clauses
    menuAction("Open database", dbOpen).
    menuAction("Export database", dbExport).

[Thomas Linder Puls]

The short answer is no. facts are very different from each other (different number of arguments of different types).

But if we are for example considering fact variables of type string, then you can assert getter and the setter predicates.

Code: Select all

class facts
    namedProperty : (string Name, function{string} Get, predicate{string} Set).
 
clauses
    namedProperty("aaa", {  = aaa }, { (S) :- aaa := S }).
    namedProperty("bbb", {  = bbb }, { (S) :- bbb := S }).

But there is no simple syntax for this.

(You will most likely not need a fact for this, because it is not likely that you are going to invent additional facts, getters and setters while during program run).

[Harrison Pratt]

Very clear answer -- thank you!