The ALLCOT language: a first overview

Strictly speaking, the ALDOR language is not an object oriented language. Indeed, its notion of a domain is richer than a class (like a JAVA class). However, the ALLCOT language, because of its restrictions w.r.t. ALDOR, will essentially be a simple object oriented language.

In the above example OddNumbers and Word are classes in the sense that

• the values of these types are encoded by means of attributes that are not visible outside of the class,
• each function of these types is morally either a method (that is, a function whose first argument is of the type where the function is defined) or a creator (that is, a function which returns a value of the type where the function is defined).

In the above example, Monoid, WordMonoid and MonoidOfZ are interfaces in the sense that each of them is a list of function declarations. Note that both WordMonoid and MonoidOfZ inherit from Monoid. Observe also that

• on the contrary of JAVA, creators like one, convert or word are allowed in a category,
• the syntax of an ALLCOT function declaration is rather that of PASCAL than that of C or JAVA.

Observe also the role of the symbol %.

• In one of the categories Monoid, WordMonoid or MonoidOfZ, this symbol means an element of a domain implementing this category.
• In one of the domains OddNumbers and Word, this symbol means an element of this domain.

Finally, observe the different kinds of equality-like symbols.

==

is used for a category definition, a domain definition or a function definition. In fact, in aldor it is used for a constant definition, that is for the definition of some variable whose value cannot change.

:=

is used for a variable definition (whose value can change).

=

is used for the equality test.