Ada Programming/Attributes/'Range

Attributes 'Range __TOC__ Description The meaning of the attribute depends on the meaning of the prefix X. If X is a scalar subtype, X'Range represents the range of valid values for that subtype, i.e. it is the same as the subtype itself. If X is a constrained array subtype or an array object, X'Range denotes the index range of X. In any case, X'Range is equivalent to X'First .. X'Last, but X is only evaluated once. If X is multidimensional, the attribute needs a static parameter N to identify the N-th index; 'Range (1) is the same as 'Range. X'Range (N) is equivalent to X'First(N) .. X'Last(N), but X is only evaluated once. Examples type T is range 1double_dot ..10; T'Range is equal to T type A is array (T) of S; these three A'Range is the same as T type A is array (T'Range) of S; declarations type A is array (T'First double_dot .. T'Last ) of S; are equivalent type B is array (T range box <>) of S; B'Range is illegal (B is unconstrained) subtype SB is B (2 double_dot .. 5); SB'Range is the same as 2 .. 5 type M is array (Boolean, T) of S; M'Range is equivalent to M'Range (1), which is Boolean M'Range (2) is the same as T OA: A; OA'Range is the same as T OB: B (2 double_dot .. 5); OB'Range is equal to 2 .. 5 See also Wikibook Ada Programming Ada Reference Manual 13 3 Operational and Representation Attributes K Language-Defined Attributes Range