190 likes | 302 Views
Definitions. Given sets. Given sets : examples. To introduce declaration of a set of student ; [ student ] In a library management system, the type Book and Person can be introduced as given sets : [ Book, Person ]. Declaration of variables.
E N D
Given sets : examples • To introduce declaration of a set of student ; [ student ] • In a library management system, the type Book and Person can be introduced as given sets : [ Book, Person ]
Declaration of variables • A name is assigned a type when it is declared. Once a given set is declared, we can declare variables. • Example stud1 : Student --- declaring a student library1 : pBook --- declaring a set of books primes : p --- declaring primes to be a set of integers newestbook : Book --- what the book is and a number showing the copy library : p(Book ) --- declaring a library as a set of copies of books
Abbreviations • Syntactic equivalence • Example basic_ref == {math, intro_to_computers} • Is equivalent to the declaration basic_ref : p Book together with the predicate basic_ref = {math, intro_to_computers}
Enumerated types • Use data type definition to introduce a type with a small number of members • Name ::= list of elements separated by | • Example YesNo ::= yes | no
Axiomatic description • To introduce variables along with predicates giving further information