[fpc-pascal] Documentation, syntax diagrams

[Howard Page-Clark]

On 08/01/2014 20:01, Sven Barth wrote:
> 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.

Thanks for the clarification. That is a distinction worth drawing 
attention to in the documentation, and its relevance when writing 
overloaded routines.
Looks like the obtuseness is at this end, as well as at Jürgen's.

Howard