Nothing In Particular

Subjects that don't have their own home
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#14971 Re: Nothing In Particular

Post by andrew Ivimey »

No manhole covers on Hadrian's Wall!

Guess where I am...the wind is hugely 'compelling'.

What did the Romans ever do for us!?
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
jack
Thermionic Monk Status
Posts: 5493
Joined: Wed Dec 29, 2010 8:58 pm
Location: ɐılɐɹʇsnɐ oʇ ƃuıʌoɯ ƃuıɹǝpısuoɔ
Contact:

#14972 Re: Nothing In Particular

Post by jack »

Nick wrote: Fri Nov 11, 2022 2:08 pm
Really? If you just define a class, it hasn't been instantiated, so doesn't exist other than as a concept - there is no tangible reality at that point.
But what if you create a pointer to that class, but leave it set to NULL. Does the class exist then?
No. All you have is a NULL pointer.
It's like you define what a "cup" is, say, in a dictionary. At that point no cup exists... however as soon as you use that description to make a cup, one exists...
But what if you use the description to make a cupholder? what then?
It's simply a matter of inheritance - the cupholder is a derived class of cup, presumably using several private class members, i.e. dimensions etc. which would have to be specified in the class constructor... Simple OO design.

So, to make the cupholder, you would implicitly instantiate a cup as a subclass of cupholder...
Vivitur ingenio, caetera mortis erunt
User avatar
Nick
Site Admin
Posts: 15710
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#14973 Re: Nothing In Particular

Post by Nick »

jack wrote: Fri Nov 11, 2022 4:49 pm
Nick wrote: Fri Nov 11, 2022 2:08 pm
Really? If you just define a class, it hasn't been instantiated, so doesn't exist other than as a concept - there is no tangible reality at that point.
But what if you create a pointer to that class, but leave it set to NULL. Does the class exist then?
No. All you have is a NULL pointer.
But you don't, you have a NULL pointer to a cup, if you try and make it point to a fork, it the compiler will object. Even though there are no cups in existence, it can have a "real" effect.
Jack wrote:
Nick wrote:
Jack wrote: It's like you define what a "cup" is, say, in a dictionary. At that point no cup exists... however as soon as you use that description to make a cup, one exists...
But what if you use the description to make a cupholder? what then?
It's simply a matter of inheritance - the cupholder is a derived class of cup, presumably using several private class members, i.e. dimensions etc. which would have to be specified in the class constructor... Simple OO design.

So, to make the cupholder, you would implicitly instantiate a cup as a subclass of cupholder...
Ah, but here I was using your description of a cup in the real world, not a OO one. If you use the description of a cup to create a object that occupies the space a cup doesn't then while no cup exists, its non existence is then manifold in reality. Its like the lovely description I saw ones of a luthier taking a piece of wood and removing everything that wasn't part of a guitar.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
jack
Thermionic Monk Status
Posts: 5493
Joined: Wed Dec 29, 2010 8:58 pm
Location: ɐılɐɹʇsnɐ oʇ ƃuıʌoɯ ƃuıɹǝpısuoɔ
Contact:

#14974 Re: Nothing In Particular

Post by jack »

Nick wrote: Fri Nov 11, 2022 5:06 pm
jack wrote: Fri Nov 11, 2022 4:49 pm
Nick wrote: Fri Nov 11, 2022 2:08 pm

But what if you create a pointer to that class, but leave it set to NULL. Does the class exist then?
No. All you have is a NULL pointer.
But you don't, you have a NULL pointer to a cup, if you try and make it point to a fork, it the compiler will object. Even though there are no cups in existence, it can have a "real" effect.
Nope, you have pointer that could one day maybe point to a cup, but importantly, at the moment there is no cup to point to. Just because you have a finger on your hand that could potentially point to a cup, that doesn't imply, even implicitly, that cups exist. Using reducto ad absurdum, my finger could point to anything I could imagine, so does that mean that everything that I could image exists? No.

Trying to leverage strong typing as proof of existence is a non sequitur - as you are well aware, a typedef is a description of what an object would be, if it's ever instantiated. In this case, just because you have a description of a cup and specified that a pointer is only allowed to point to a cup (or nothing), does not in itself imply, let alone prove, that any cups actually are extant.
Jack wrote:
Nick wrote: But what if you use the description to make a cupholder? what then?
It's simply a matter of inheritance - the cupholder is a derived class of cup, presumably using several private class members, i.e. dimensions etc. which would have to be specified in the class constructor... Simple OO design.

So, to make the cupholder, you would implicitly instantiate a cup as a subclass of cupholder...
Ah, but here I was using your description of a cup in the real world, not a OO one. If you use the description of a cup to create a object that occupies the space a cup doesn't then while no cup exists, its non existence is then manifold in reality. Its like the lovely description I saw ones of a luthier taking a piece of wood and removing everything that wasn't part of a guitar.
You can create a cupholder from a description of a cup - you don't need an instance of a cup to manifest that.
Vivitur ingenio, caetera mortis erunt
simon
Thermionic Monk Status
Posts: 5600
Joined: Thu May 24, 2007 11:22 am
Location: People's Republic of South Yorkshire

#14975 Re: Nothing In Particular

Post by simon »

Nick wrote: Fri Nov 11, 2022 1:15 pm
That's a bit niche Nick
On a thread that's wandered into collecting manhole covers I am not sure that there is any more niche it could be.
Fair point. OTOH pretty much everyone knows what a manhole is, but there won't be too many that understood the conversation that followed.
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#14976 Re: Nothing In Particular

Post by ed »

good 'ere innit

otoh Jack is trying very hard to convince us that he's lost his sense of humour.....

I'll see your Null pointer and raise you one Higgs boson 40 years ago.
There's nowhere you can be that isn't where you're meant to be
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#14977 Re: Nothing In Particular

Post by pre65 »

simon wrote: Fri Nov 11, 2022 5:38 pm
Nick wrote: Fri Nov 11, 2022 1:15 pm
That's a bit niche Nick
On a thread that's wandered into collecting manhole covers I am not sure that there is any more niche it could be.
Fair point. OTOH pretty much everyone knows what a manhole is, but there won't be too many that understood the conversation that followed.
Maybe not understood, but entertaining. :)
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
jack
Thermionic Monk Status
Posts: 5493
Joined: Wed Dec 29, 2010 8:58 pm
Location: ɐılɐɹʇsnɐ oʇ ƃuıʌoɯ ƃuıɹǝpısuoɔ
Contact:

#14978 Re: Nothing In Particular

Post by jack »

ed wrote: Fri Nov 11, 2022 6:18 pm good 'ere innit

otoh Jack is trying very hard to convince us that he's lost his sense of humour.....

I'll see your Null pointer and raise you one Higgs boson 40 years ago.
Nah. It's just t'other Nick playing Devil's Advocate... a process of attrition, seeing which of us gets bored first!

Blimey! This is page 999!!!! What a load of bollocks...
Vivitur ingenio, caetera mortis erunt
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#14979 Re: Nothing In Particular

Post by IslandPink »

I'll try to use my special knack for throwing pages to achieve some sort of small victory here ...

Update : D'oh !
"Once you find out ... the Circumstances ; then you can go out"
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#14980 Re: Nothing In Particular

Post by andrew Ivimey »

Bollocks - well yes even though I too hadn't a clue. And if no one wants to discuss anything as useless as the development of western thinking well we may as well think about manhole covers.
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
Dave the bass
Amstrad Tower of Power
Posts: 12273
Joined: Tue May 22, 2007 4:36 pm
Location: NW Kent, Darn Sarf innit.

#14981 Re: Nothing In Particular

Post by Dave the bass »

Question from the dim kid at the back of the class.

Whats the difference between Eastern and Western thinking Sir?
"The fat bourgeois and his doppelganger"
User avatar
shane
Social outcast
Posts: 3403
Joined: Sun Sep 16, 2007 12:09 pm
Location: Kept in a cool dry place.

#14982 Re: Nothing In Particular

Post by shane »

I have no idea what this is about.
The world looks so different after learning science. For example, trees are made of air, primarily. When they are burned, they go back to air, and in their flaming heat is released the flaming heat of the Sun which was bound in to convert air into tree.
User avatar
jack
Thermionic Monk Status
Posts: 5493
Joined: Wed Dec 29, 2010 8:58 pm
Location: ɐılɐɹʇsnɐ oʇ ƃuıʌoɯ ƃuıɹǝpısuoɔ
Contact:

#14983 Re: Nothing In Particular

Post by jack »

Dave the bass wrote: Fri Nov 11, 2022 8:27 pm Whats the difference between Eastern and Western thinking Sir?
Curry vs pizza innit?
Vivitur ingenio, caetera mortis erunt
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#14984 Re: Nothing In Particular

Post by IslandPink »

Ha !

Edit : damn, still no success !
"Once you find out ... the Circumstances ; then you can go out"
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#14985 Re: Nothing In Particular

Post by andrew Ivimey »

It happens Mark. Now was it worth it?
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
Post Reply