Mailing lists / fpc-devel / 2015-08
Records nesting/inheritance?
5 messages · 3 people ·
- Чернов Дмитрий 3
- Michael Van Canneyt 1
- Sven Barth 1
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"Чернов Дмитрий" wroteSo, there's examples of addressing some fields with and without this
feature:
Show quoted text 8 lines
Friend.BaseUser.FirstName >> Friend.FirstName
Friend.UserInfo.Country.ID >> Friend.Country.ID
And let me clarify some details:
- fields can not be overridden;
- record can nest several records.
Of course, somebody will try to advise me to use objects. :)
Of course, but probably not the objects you think about ("class"), but their older cousins ("object"). ;)
But never mind that a) in procedural programming we don't use objects,
"object" types behave like records with inheritance if they don't have methods.
b) objects are more complex that needed
Not true for "object" types.
c) objects require additional routines for creating and destroying of
them.
Like records "object" types can be allocated on the stack.
So there is no need to burden "record" with another feature that's already supported by "object".
Note: Multiple inheritance is however supported by none of the three structured types ("record", "object", "class") and it wouldn't be added anyway, so there you need to find a solution with normal inheritance.
Regards,
Sven
Чернов Дмитрий wrote 12 lines
Good day everyone.
Recently I've tried to write some social network parsing code and faced with numerous nesting of structures (records).
When I completely tired to write things like Friend.BaseUser.City.ID ("real programmer will never get complerely tired", hah - yes, I know), I thought out that it might be cool to have such a
feature as structures inheritance.
I'm not very good in English, so, instead of describing everything I'll just try to write an example:
http://pastebin.com/Pm701Nh4
So, there's examples of addressing some fields with and without this feature:
Friend.BaseUser.FirstName >> Friend.FirstName
Friend.UserInfo.Country.ID >> Friend.Country.ID
You can do this already with extended records, just declare properties.
http://www.freepascal.org/docs-html/ref/refse51.html#x107-1170009.1
Michael.
05.08.2015, 16:20, "Michael Van Canneyt" :
Show quoted text 25 lines
On Wed, 5 Aug 2015, Чернов Дмитрий wrote:
> Good day everyone.
>
> Recently I've tried to write some social network parsing code and faced with numerous nesting of structures (records).
> When I completely tired to write things like Friend.BaseUser.City.ID ("real programmer will never get complerely tired", hah - yes, I know), I thought out that it might be cool to have such a
> feature as structures inheritance.
> I'm not very good in English, so, instead of describing everything I'll just try to write an example:
>
> http://pastebin.com/Pm701Nh4
>
> So, there's examples of addressing some fields with and without this feature:
> Friend.BaseUser.FirstName >> Friend.FirstName
> Friend.UserInfo.Country.ID >> Friend.Country.ID
You can do this already with extended records, just declare properties.
http://www.freepascal.org/docs-html/ref/refse51.html#x107-1170009.1
Michael.
,
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You can do this already with extended records, just declare properties.…