Re: on package naming, should the word "_pkg" be part of it?

[Jeffrey Carter <jeffrey.carter@boeing.com>]

Stephen Leake wrote:
> 
> I use _Type. The reason is that types and objects share the same
> namespace, yet the most reasonable name for an object and a type is
> the same:
> 
> type Car is record ... end record;
> 
> Car : Car;
> 
> This is natural, but illegal. The easiest (for _me_, not for
> everyone!) way to resolve it is to add some "noise" to either the
> object or the type. Since the object name will appear more often than
> the type, I add noise to the type:

No, it's not natural. What might be natural is

VIN_ABC1234567JKLK67 : Car;

or

Car : Chevy_1957;

More realistically,

Current_Vehicle : Car;

Even this is incorrect. Current_Vehicle is not a car, it is a collection
of information about a car:

Current_Vehicle : Car_Info;

The developer thinks, "This type is a collection of information about
cars, so its name should be Collection_Of_Information_About_Cars, or
Car_Info for short." Or something like that.

Further, there is generally no problem with object names, since objects
of the type are generally not declared in the same scope:

Car : Car_Handler.Car;

It is parameter names defined in the same scope that are perceived as a
problem. In many cases, even parameter names are not a problem. When
inserting into a list, Into seems a better parameter name than List;
when iterating over a structure, Over seems better than List, Queue, or
Stack, and so on.

Maybe _Info is still noise, but it seems like more reasoned noise than
_Type. If the object is simply to put some noise on the end of type
names to distinguish them from parameter names, then _T seems as good as
any other noise.

Another "solution" I have seen is

package Types is
   type Bicycle is ...

   type Car is ...

   type Number is ...

   type Rainfall_Sensor_Reading is ...

   ...
end Types;

with Types;
package Functions is
   function Bicycle_Speed (Bicycle : Types.Bicycle) return Types.Number;

   function Car (Number : Types.Number) return Types.Car;

   function Car_Speed (Car : Types.Car) return Types.Number;

   ...
end Functions;

Never a name problem!

Even noise is better than this.

-- 
Jeffrey Carter