[fpc-pascal] Documentation, syntax diagrams

[Sven Barth]

On 08.01.2014 19:40, Howard Page-Clark wrote:
> On 08/01/2014 18:16, Jürgen Hestermann wrote:
>>
>> Today I found this type definition in some FreePascal sources:
>>
>> TypeReal =type Double;
>>
>> I wondered what the second “type” keyword means here (I have never seen
>> this before).
>
> You are being rather obtuse.
> Ignore the diagrams in the docs if they don't help you.
>
> The double use of type here simply means that the "Real" type is being
> defined as an alias for double. The two type identifiers now mean
> exactly the same thing as the "=" indicates.

No, an alias would be

=== code begin ===

type
   Real = Double;

=== code end ===

Using the "type" behind the "=" tells the compiler to declare a new type 
based on the right side. So a "Double" and a "Real" are not assignment 
compatible and can have different sets of operator overloads.

Regards,
Sven