1. [phix] if 'number' then why not 'list' ?
- Posted by _tom (admin) Feb 21, 2021
- 1095 views
An atom is:
- number
- integer
A list is:
- sequence
- string
For generic tutorial descriptions emphasis on "only two distinct data-types" is a selling point. You just have to understand "atom" and "list". If you just have to use: number, integer, sequence, string
Writing a demo program that uses just number and list gets as simple as it gets. Everyone (like non-programmers) understand what a number is and a what list is--no thinking required.
be well
_tom
2. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 1066 views
list does carry a lisp-like connotation, and the implication that random access is expensive. Maybe.
Wikipedia (groan) states "Some languages may allow list types to be indexed or sliced like array types, in which case the data type is more accurately described as an array."
And array generally implies fixed length and homogenous element type.
3. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 1065 views
- 1 is a number
- 3.1415 is a number
- "Hello" is a string
What is {1} ? (a container containing one number)
What is {1,2,3.14} ? (a container containing a sequence of 3 numbers)
What is {"Hello",1,2} ? (a container containing 1 string and 2 numbers)
What is {"Hello",{1,2,3}} ? (a container containing 1 string and 1 sequence of 3 numbers)
Maybe the word container would make the concept easier to explain?
4. Re: [phix] if 'number' then why not 'list' ?
- Posted by _tom (admin) Feb 21, 2021
- 1069 views
- 1 is a number
- 3.1415 is a number
- "Hello" is a string
What is {1} ? (a container containing one number)
What is {1,2,3.14} ? (a container containing a sequence of 3 numbers)
What is {"Hello",1,2} ? (a container containing 1 string and 2 numbers)
What is {"Hello",{1,2,3}} ? (a container containing 1 string and 1 sequence of 3 numbers)
Maybe the word container would make the concept easier to explain?
I like this suggestion. It allows me to include struct and class under "container."
be well
_tom
5. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 1055 views
Maybe the word container would make the concept easier to explain?
I like this suggestion. It allows me to include struct and class under "container."
Uh oh, i like it too. Objects in sequences do not need to be sequential.
I figured out the bug tho: down the road all incoming newbies will replace the word sequence totally with container. Eu/OE/Phix will lose this verbal claim to fame.
Kat
6. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 1057 views
Maybe the word container would make the concept easier to explain?
I like this suggestion. It allows me to include struct and class under "container."
be well
_tom
Perhaps a struc is a container containing a specified number of [typed] objects, as opposed to the freestyle sequence, which can contain anything in any quantity.
And a class is a container containing numbers, strings, sequences and/or objects, plus methods, all associated with the specific class.
7. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 1096 views
What is {1,2,3.14} ? (a container containing a sequence of 3 numbers)
What is {"Hello",{1,2,3}} ? (a container containing 1 string and 1 sequence of 3 numbers)
Minor nit-pick: assuming that 'a' and '1' mean the same thing, only one of those can be correct, and I think it's the 2nd.
Minor nit-pick number two: does that mean we now have to describe container and sequence?
Minor nit-pick number three: the phrases "sequence contains" and "sequence containing" work for me, "container contains" and "container containing" not so much.
Minor nit-pick number four: I suspect you'd have to define "container" with just as much care as "sequence"
Now over 20 years ago, Rob Craig said:
"sequences make Euphoria very simple and very powerful"
"Sequences are it - there are no other data structures to learn."
More than anything else, those two phrases still resonate deeply with me, even after all this time.
If you try and use a word that someone likely has preconceptions about, such as list or array, that loses it's punch, and pretty much stops making any sense altogether.
8. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 1097 views
What is {1,2,3.14} ? (a container containing a sequence of 3 numbers)
What is {"Hello",{1,2,3}} ? (a container containing 1 string and 1 sequence of 3 numbers)
Minor nit-pick: assuming that 'a' and '1' mean the same thing, only one of those can be correct, and I think it's the 2nd.
Minor nit-pick number two: does that mean we now have to describe container and sequence?
Minor nit-pick number three: the phrases "sequence contains" and "sequence containing" work for me, "container contains" and "container containing" not so much.
Yes. Containing 1 sequence of 3 numbers is clearer.
Yes. Trying to explain that structs and classes are also types of sequences is just going to complicate things, since they aren't really treated like other sequences.
Agreed.
9. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 1017 views
Question about class, in Phix/OE, to simplify perhaps (or too simplified?)....
Can you express class as like an include file with everything in it scoped to that thing you just classed?
Kat
10. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 1036 views
Everything in a class is scoped to an instance of that class.
11. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 1005 views
Everything in a class is scoped to an instance of that class.
So class is not like an include file?
Kat
12. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 999 views
No, you cannot have an include statement inside a class definition.
13. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 1019 views
Still not what i said.
Is a class like a include file, with everything in the include file scoped to what you declared as a class?
The what's different about "include as"?
include cow.e as cow_1 include cow.e as cow_2
Now both cows have variables and procedures and functions (from cow.e) as most cows do. Are they treated same as a class?
Kat
14. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 1008 views
Not the same. Here is a comparison:
-- contents of cow.e---- public integer horns = 0 ------------------------ include cow.e as cow1 include cow.e as cow2 cow1:horns = 2 cow2:horns = 1 ? cow1:horns ? cow2:horns
1 1
As you can see, there is only one variable to store the # of horns, even if you use different "namespaces".
On the other hand, classes provide a "horns" variable for each instance of cow, so we change cow.e so that it declares a class:
export class Cow public integer horns = 0; end class
include cow.e Cow cow1 = new() Cow cow2 = new() cow1.horns = 2 cow2.horns = 1 ? cow1.horns ? cow2.horns
2 1
More often than not, I will declare methods which are called when the number of horns on any cow is accessed, so the cow class would look more like this:
export class Cow private integer horns; procedure set_horns(integer n) this.horns = n end procedure function get_horns() return this.horns end function end class
Within those methods, you can do other stuff that might be needed, like popping up a warning if someone tries to give Bessie 3 horns...etc.
15. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 985 views
Still not what i said.
Still no idea what the question is.
Is a class like a include file, with everything in the include file scoped to what you declared as a class?
What part of "Everything in a class is scoped to an instance of that class." does not answer that question?
Now both cows have variables and procedures and functions
They most certainly do not (as irv just posted while I was typing). There is one cow that can be referenced via two namespaces.
An include statement includes a file.
A class statement defines a class.
There are some minor similarities and many more vast differences.
A new class instance can be created using new(). An include instance just is.
An include can contain global and non-global definitions, which are and are not visible.
A class can have public and private fields, but they don't exist except via an instance, and only then does externally visible or internal only apply.
"Yes they are similar" and "No they are completely different" are both true at the same time.
If you had bothered to read even the first line of the manual you would know that classes are much closer to types than include statements.
16. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 993 views
Hmm, ok. Thanks, Irv.
I hate to ask, it seems like an old question, but if i have a mammal class, can a cow class inheret from the mammal class? (speaking about Phix and OE implementations)
Kat
17. Re: [phix] if 'number' then why not 'list' ?
- Posted by petelomax Feb 21, 2021
- 968 views
Phix:Yes OE:???
However, as the Gang of Four said nearly thirty years ago, favour composition over inheritance.
18. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 986 views
- Last edited Feb 22, 2021
Hmm, ok. Thanks, Irv.
I hate to ask, it seems like an old question, but if i have a mammal class, can a cow class inheret from the mammal class? (speaking about Phix and OE implementations)
Kat
Phix, yes. OE, no.
That's exactly where classes are useful. e.g:
export class Mammal public string gender; end class export class Whale extends Mammal end class export class Cow extends Mammal public integer horns; end class
include Cow.e Cow Bossie = new() Cow Ferdinand = new() Bossie.gender = "female" Ferdinand.horns = 2 Whale Nemo = new() Nemo.gender = "male" Nemo.horns = 2 -- no such field (horns) is the error message;
You'll note that it isn't necessary for your program to specifically include a file declaring the Mammal class. The Cattle file will include that, and look for the "gender" variable in that class (or classes, as the case may be - multiple inheritance is easy to do, the planning part is difficult.)
19. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 21, 2021
- 956 views
If you had bothered to read even the first line of the manual you would know that classes are much closer to types than include statements.
I don't know where my reply to that went, but it's been 5 minutes or so...
Since i was working around the type system to make shared variables possible, i first considered type. But type as implemented in OE, doesn't let the programmer know the variable name being type-checked. I had to jump hoops to get that data. And the code written (procedures and functions) aren't exclusively naturally available to the variable the type check was written for. And finally, the resulting code block would/could look like an include file. Which is how i got to asking about "class" vs "include as".
Kat
20. Re: [phix] if 'number' then why not 'list' ?
- Posted by irv Feb 21, 2021
- 981 views
Since i was working around the type system to make shared variables possible, i first considered type. But type as implemented in OE, doesn't let the programmer know the variable name being type-checked. I had to jump hoops to get that data. And the code written (procedures and functions) aren't exclusively naturally available to the variable the type check was written for. And finally, the resulting code block would/could look like an include file. Which is how i got to asking about "class" vs "include as".
Kat
Yep. When Rob first implemented the "include as", it was possible to do multiple includes under different namespaces, and have separate instances of a variable. That didn't last long, he quickly "fixed" it - presumably due to side effects (he didn't share). If it had been combined with an improved type() implementation, as you point out, Euphoria would have had OOP decades ago - but probably not with inheritance. Phix does that nicely.
21. Re: [phix] if 'number' then why not 'list' ?
- Posted by katsmeow Feb 22, 2021
- 913 views
Yep. When Rob first implemented the "include as", it was possible to do multiple includes under different namespaces, and have separate instances of a variable. That didn't last long, he quickly "fixed" it - presumably due to side effects (he didn't share).
Thank you Irv, it's been enlightening.
With a slight change to the shared variables preprocessor, i can include cow.e as something file many times, once for each umm, situation, being it's understood every variable and code block has a different name, based on the something in the include declaration, accessed approximately like class naming does. It's only a way to get around the "fix" Rob did to the original "bug", and it's going to grow the load time and memory use accordingly.
Kat
