variablereference

#variableReference

##Syntax A variableReference is:

variableId { componentSelector }

##Description In a Turing program, a variable is declared and given a name (variableId) and then used. Each use is called a variable reference.

If the variable is an array, collection, record or union, its parts (components) can be selected using subscripts and field names (using componentSelectors). The form of a componentSelector is one of:\

(a) ( expn {, expn} ) (b) . fieldId

Form (a) is used for subscripting (indexing) arrays and collections. The number of array subscripts must be the same as in the array's declaration. A collection has exactly one subscript, which must be a pointer to the collection. Form (b) is used for selecting a field of a record or union.

##Example Following the declarations of k, a and r, each of k, a (k) and r.name are variable references.

    var k : int
    var a : array 1 .. 100 of real
    var r :
        record
            name : string ( 20 )
            phone : string ( 8 )
        end record
    �
    k := 5
    a ( k ) := 3.14159
    r . name := "Steve Cook"

##Details A variable reference can contain more than one component selector, for example, when the variable is an array of records. For an example, see the record type. See also constantReference and var declaration.