numeric base types

numeric base types

[Bryan]

 

>>Are all numeric base types anonymous? 

All the following must be true:

	Short_Integer'First = Short_Integer'Base'First
	Short_Integer'Last  = Short_Integer'Base'Last
	Integer'First       = Integer'Base'First
	Integer'Last        = Integer'Base'Last
	Long_Integer'First  = Long_Integer'Base'First
	Long_Integer'Last   = Long_Integer'Base'Last

	RM 3.5.4(7), 3.5.7(8)

All base type are either predefined or anonymous.  The same is true
for the predefined fixed point types.  The base type of the predefined integer
and fixed point types is the type itself.

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>>Concerning safe numbers, consider:
>>	type F is digits 4;
>>May it be true that F'Safe_Small < F'Small?  May safe numbers exist within
>>a model interval? 
>>Must it be true that

For any floating point type F:

	F'Safe_Small      <= F'Small
	F'Base'Safe_Small  = F'Safe_Small
	F'Base'Digits     >= F'Digits

	RM  3.5.8(18).

The safe numbers of a fixed point type are the model numbers of its base
type (RM 3.5.9/11).  As far as I can tell, Duration need not be its own
base type.

doug
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