Ada Programming/Attributes/'Range
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[edit] Description
X'Range is an Ada attribute that may be used in three ways.
If X is a discrete type, the X'Range represents the range of valid values for that type.
If X is an array type, then the attribute may be used with or without an input parameter Y. Y represents an index into the array type. The attribute represents the range of valid values for an index of X.
In all three cases, the X'Range is equivalent to X'First .. X'Last -- but X is only evaluated once.
[edit] Example
If you declare:
type My_Enum is (Enum1, Enum2, Enum3); type My_Array is array (MyEnum, Integer) of Boolean;
then
My_Enum'Range = Enum1 .. Enum3 My_Array'Range(1) = Enum1 .. Enum3 My_Array'Range(2) = Integer'First .. Integer'Last My_Array'Range = My_Array'Range(1)
