Re: Ada Quality and Style book discussion ("_Type" suffix)

["Jeffrey R. Carter" <spam@spam.com>]

Anonymous Coward wrote:
> Suffixes are *very* useful, as I will illustrate.  It's no coincidence
> that well named, direct, concise type names very often match
> (verbatim) good names for objects (including enums), in the absense of
> a type suffix.

GOOD suffixes are very useful. _Type is a bad suffix. As AC himself says 
elsewhere, "If you're repeating information from your declaration in your 
identifiers, then you've created a maintenance problem by introducing too much 
noise". "type X_Type" clearly repeats information from the declaration in the 
identifier.

Prefixes are very bad. The 1st few characters of an identifier are the most 
important in determining what it is. If lots of identifiers start with the same 
sequence of characters, it makes reading harder.

My personal preferences are

>       type Day is (Monday, Tuesday,  Wednesday, Thursday,

Day_ID

>       type Meters is new Float;

Meter_Value

>       type Feet is new Float;

Foot_Value

>       type Length is (Feet, Meters, Miles);

Length_ID

>       Speed : Speed;

Global variables are extremely bad. But consider

procedure P (Speed : in Speed_Value);

In well designed systems, packages tend to contain a type and operations on that 
type; objects of the type are generally declared elsewhere, and in any case 
represent specific things, not the general concept of the type, so the issue 
rarely comes up.

That said, I've worked on projects where _Type was mandated, and it works 
reasonably well. I got irritated every time I typed _Type, but the resulting 
code was readable.

-- 
Jeff Carter
"I'm a kike, a yid, a heebie, a hook nose! I'm Kosher,
Mum! I'm a Red Sea pedestrian, and proud of it!"
Monty Python's Life of Brian
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