Re: Aliasing [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 11:00 PM, Steve D'Aprano wrote: > The critical distinction here is whether the names refer to each other: > >a <---> b > >or whether they merely refer to the same value: > >a ---> [ value ] <--- b > > >Python uses the second model. Var parameters

Re: Aliasing [was Re: [Tutor] beginning to code]

Op 27-09-17 om 09:38 schreef Steven D'Aprano: No, the model that C++ and Pascal use is not different in this aspect. > that Pascal var parameters and C++ reference variables operate the same > way as Python variable assignment, the *kindest* thing I can say is that > you are ignorant. The

Re: Aliasing [was Re: [Tutor] beginning to code]

Op 27-09-17 om 10:11 schreef Chris Angelico: > On Wed, Sep 27, 2017 at 5:38 PM, Steven D'Aprano > wrote: >> Twice you have claimed to be able to write such a swap procedure for >> lists. You can't. If you think you can, it is only because you have >>

Re: Aliasing [was Re: [Tutor] beginning to code]

On Wed, Sep 27, 2017 at 5:38 PM, Steven D'Aprano wrote: > Twice you have claimed to be able to write such a swap procedure for > lists. You can't. If you think you can, it is only because you have > misunderstood the problem and are writing something else

Re: Aliasing [was Re: [Tutor] beginning to code]

On Wed, 27 Sep 2017 08:56:03 +0200, Antoon Pardon wrote: >> But that's not enough for the variable b to be an alias for the >> variable a. > > Yes it is! Since you seem to be intent on inventing your own meanings for well established words, for the confusion and misinformation of all, I can

Re: Aliasing [was Re: [Tutor] beginning to code]

Op 27-09-17 om 04:58 schreef Steve D'Aprano: > A pedantic difference that makes no difference to my argument. > > I see that you ignored the later assignment: > > b = 2; > > which also assigned to a. *That** is the fundamental point: b is certainly an > alias for a, and assigning to b assigns to

Re: Aliasing [was Re: [Tutor] beginning to code]

Op 27-09-17 om 04:58 schreef Steve D'Aprano: > On Wed, 27 Sep 2017 02:03 am, Stefan Ram wrote: > >> Steve D'Aprano writes: >>> On Tue, 26 Sep 2017 03:26 am, Antoon Pardon wrote: at that moment, but it still needed correction. If the assignment is an alias

Re: Aliasing [was Re: [Tutor] beginning to code]

Steve D'Aprano wrote: On Wed, 27 Sep 2017 02:03 am, Stefan Ram wrote: Steve D'Aprano writes: On Tue, 26 Sep 2017 03:26 am, Antoon Pardon wrote: at that moment, but it still needed correction. If the assignment is an alias operator then after the statements

Re: Aliasing [was Re: [Tutor] beginning to code]

On Wed, 27 Sep 2017 02:03 am, Stefan Ram wrote: > Steve D'Aprano writes: >>On Tue, 26 Sep 2017 03:26 am, Antoon Pardon wrote: >>>at that moment, but it still needed correction. If the assignment is >>>an alias operator then after the statements >>Here's some C++ code

Re: Aliasing [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 12:00 PM, Steve D'Aprano wrote: > > a = 1 >> b = a >> b = 2 >> >> a is not 2. > < snip > int main () { > int a; > int& b = a; // reference variable or alias > > a = 1; > printf("a: %d, alias b: %d\n", a, b); > b = 2; > printf("a:

Re: Call by binding [was Re: [Tutor] beginning to code]

Rhodri James : > On 25/09/17 20:40, Marko Rauhamaa wrote: >> A pointer is something that points to a data object. > > In that case you are using "pointer" in such an informal sense that > making deductions from it is unlikely to be successful. Propose a name for the

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Wed, Sep 27, 2017 at 5:24 AM, Grant Edwards wrote: > On 2017-09-26, alister via Python-list wrote: >> On Tue, 26 Sep 2017 14:16:47 +, Grant Edwards wrote: >> >>> On 2017-09-26, Ned Batchelder wrote: On

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 2017-09-26, alister via Python-list wrote: > On Tue, 26 Sep 2017 14:16:47 +, Grant Edwards wrote: > >> On 2017-09-26, Ned Batchelder wrote: >>> On 9/25/17 10:20 PM, Steve D'Aprano wrote: On Tue, 26 Sep 2017 02:54 am, Ned Batchelder

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 2017-09-26 18:25, alister via Python-list wrote: >>> We've been asked nicely by the list mod to stop :) >> >> Perhaps we could agree on a subject line tag to be used in all >> threas arguing about what to call the Python argument passing >> scheme? That way the other 99% of us could

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Wed, Sep 27, 2017 at 4:25 AM, alister via Python-list wrote: > On Tue, 26 Sep 2017 14:16:47 +, Grant Edwards wrote: > >> On 2017-09-26, Ned Batchelder wrote: >>> On 9/25/17 10:20 PM, Steve D'Aprano wrote: On Tue, 26 Sep 2017 02:54 am,

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Tue, 26 Sep 2017 14:16:47 +, Grant Edwards wrote: > On 2017-09-26, Ned Batchelder wrote: >> On 9/25/17 10:20 PM, Steve D'Aprano wrote: >>> On Tue, 26 Sep 2017 02:54 am, Ned Batchelder wrote: >>> [...] >>> >>> >>> >> We've been asked nicely by the list mod to stop

Re: Aliasing [was Re: [Tutor] beginning to code]

On 26-09-17 14:28, Steve D'Aprano wrote: > On Tue, 26 Sep 2017 03:26 am, Antoon Pardon wrote: > >> Sorry, what he wrote contradicts that. Maybe he was just really confused >> at that moment, but it still needed correction. If the assignment is >> an alias operator then after the statements >> >>

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 26/09/2017 15:16, Grant Edwards wrote: On 2017-09-26, Ned Batchelder wrote: On 9/25/17 10:20 PM, Steve D'Aprano wrote: On Tue, 26 Sep 2017 02:54 am, Ned Batchelder wrote: [...] We've been asked nicely by the list mod to stop :) Perhaps we could agree on a

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 2017-09-26, Ned Batchelder wrote: > On 9/25/17 10:20 PM, Steve D'Aprano wrote: >> On Tue, 26 Sep 2017 02:54 am, Ned Batchelder wrote: >> [...] >> >> > > We've been asked nicely by the list mod to stop :) Perhaps we could agree on a subject line tag to be used in all

Aliasing [was Re: [Tutor] beginning to code]

On Tue, 26 Sep 2017 03:26 am, Antoon Pardon wrote: >>> I'm not sure that Steve knows how it works. When he denies that the >>> assignment is an alias operation in Python that casts an important doubt. >> >> I can assure you that Steve knows how it works. Again, the disagreement is >> almost

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25/09/17 21:00, Tim Golden wrote: (Slight sigh). Can I step in as a list owner and ask the people who are so very fond of debating this topic again and again: please let it drop. But, but... someone on the internet is wrong!

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25/09/17 20:40, Marko Rauhamaa wrote: Rhodri James : On 25/09/17 15:26, Marko Rauhamaa wrote: That's not what I said. I said all expressions *evaluate to* pointers. This may well be true in particular implementations, but it is an implementation detail so Chris'

Re: Call by binding [was Re: [Tutor] beginning to code]

Chris Angelico : > I've explained Python's (or JavaScript's, since they're the same) > object model to a number of novice programmers without any > difficulties, without talking about pointers or invisible values or > any of that junk. There are just two things to explain: the

Re: [Tutor] beginning to code

Op 25-09-17 om 21:44 schreef Ned Batchelder: > > Wikipedia has the right definition of call by reference > (https://en.wikipedia.org/wiki/Evaluation_strategy#Call_by_reference): > >    /Call by reference/ (also referred to as /pass by reference/) is an >    evaluation strategy where a function

Re: [Tutor] beginning to code

Antoon Pardon wrote: It also says: This typically means that the function can modify the variable used as argument, something Python can do that. No, it can't. It can modify the *object* bound to the variable, but *not* the variable itself. If you think it can, then you're misunderstanding

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 4:25 PM, Gregory Ewing wrote: > Neil Cerutti wrote: >> >> The quest to find a succinct way to categorize Python's argument >> passing for non-Python programmers strikes me as a sincere effort >> to to simplify something that just isn't simple.

Re: Call by binding [was Re: [Tutor] beginning to code]

Neil Cerutti wrote: The quest to find a succinct way to categorize Python's argument passing for non-Python programmers strikes me as a sincere effort to to simplify something that just isn't simple. I don't see how it's useful to do that in the first place. Under what circumstances would you

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 9/25/17 10:20 PM, Steve D'Aprano wrote: On Tue, 26 Sep 2017 02:54 am, Ned Batchelder wrote: [...] We've been asked nicely by the list mod to stop :) --Ned. -- https://mail.python.org/mailman/listinfo/python-list

Re: Call by binding [was Re: [Tutor] beginning to code]

Tim Golden wrote: On 25/09/2017 20:40, Marko Rauhamaa wrote: Rhodri James : On 25/09/17 15:26, Marko Rauhamaa wrote: That's not what I said. I said all expressions *evaluate to* pointers. This may well be true in particular implementations, but it is an implementation

Re: Call by binding [was Re: [Tutor] beginning to code]

Chris Angelico wrote: On Tue, Sep 26, 2017 at 5:35 AM, Marko Rauhamaa wrote: Chris Angelico : On Tue, Sep 26, 2017 at 12:26 AM, Marko Rauhamaa wrote: Sorry, that was my bad in the terminology. But where do you get that all Python

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Tue, 26 Sep 2017 02:54 am, Ned Batchelder wrote: [...] Heh, its hard to avoid getting sucked into the sinkhole of definitional debates, isn't it? :-) [...] > But in this line: > > x = 2 + 2 > > You can say, > > the value of x is 4 If we're talking about the highest level abstraction

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 25-09-17 18:29, Steve D'Aprano wrote: > > Regardless of whether I'm using Python, Swift, Java, C, Pascal or Scheme, if I > write something like: > > x = Parrot(name="Polly") > > (using Python syntax for simplicity) and somebody tries to tell me that the > value of x is anything but a Parrot

Re: [Tutor] beginning to code

On 25-09-17 21:44, Ned Batchelder wrote: > On 9/25/17 5:32 AM, Antoon Pardon wrote: >> Can you explain, what you mean by "Pass-By-Reference" as far a I understand, >> pass by reference means that the parameter of the function becomes an alias >> of the argument, so that if the entity is mutated

Re: Call by binding [was Re: [Tutor] beginning to code]

Chris Angelico : > On Tue, Sep 26, 2017 at 5:36 AM, Marko Rauhamaa wrote: >> Chris Angelico : >>> You need *some* support for your assertion that there are pointers, >> >> What would convince you? > > Evidence, or a statement from the

Re: [Tutor] beginning to code

On Tue, Sep 26, 2017 at 5:51 AM, Stefan Ram wrote: > Ned Batchelder writes: >>Wikipedia has the right definition of call by reference > > Assertions can be right or wrong. > > Definitions cannot be right or wrong. You have made two

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 5:36 AM, Marko Rauhamaa wrote: > Chris Angelico : >> You need *some* support for your assertion that there are pointers, > > What would convince you? Evidence, or a statement from the documentation. ChrisA --

Re: Call by binding [was Re: [Tutor] beginning to code]

Rhodri James : > On 25/09/17 15:26, Marko Rauhamaa wrote: >> That's not what I said. I said all expressions *evaluate to* pointers. > > This may well be true in particular implementations, but it is an > implementation detail so Chris' point still stands. Another >

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 5:35 AM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Tue, Sep 26, 2017 at 12:26 AM, Marko Rauhamaa wrote: >> Sorry, that was my bad in the terminology. But where do you get that >> all Python expressions evaluate

Re: Call by binding [was Re: [Tutor] beginning to code]

Chris Angelico : > On Tue, Sep 26, 2017 at 12:26 AM, Marko Rauhamaa wrote: > Sorry, that was my bad in the terminology. But where do you get that > all Python expressions evaluate to pointers? What do they evaluate to if not pointers? Anton's "identities"

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 4:30 AM, Antoon Pardon wrote: > On 25-09-17 20:01, Chris Angelico wrote: >> On Tue, Sep 26, 2017 at 3:54 AM, Antoon Pardon >> wrote: >>> On 25-09-17 19:31, Chris Angelico wrote: If by "identity" you mean the

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25-09-17 20:01, Chris Angelico wrote: > On Tue, Sep 26, 2017 at 3:54 AM, Antoon Pardon > wrote: >> On 25-09-17 19:31, Chris Angelico wrote: >>> If by "identity" you mean the integer values returned by id(), then >>> nope, you're still wrong - there is no mapping

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25/09/17 15:26, Marko Rauhamaa wrote: Chris Angelico : On Mon, Sep 25, 2017 at 7:41 PM, Marko Rauhamaa wrote: In Python, all expressions evaluate pointers. And that's an assertion that isn't backed by anything in the Python specification. Where do you

Re: Call by binding [was re: [Tutor] beginning to code]

I would claim that these two paragraphs do not agree. What is stored in the variable in Pascal? In declared variables and value parameters, the value itself. Let's just temporarily stipulate that for reference parameters and pointer variables actually store a pointer to the object. Where is it

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25-09-17 19:31, Chris Angelico wrote: > On Tue, Sep 26, 2017 at 3:04 AM, Antoon Pardon > wrote: >> On 25-09-17 16:29, Marko Rauhamaa wrote: >>> Antoon Pardon : >>> Op 25-09-17 om 15:16 schreef Marko Rauhamaa: > No, I'm not. I'm

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 12:26 AM, Marko Rauhamaa wrote: > Chris Angelico : > >> On Mon, Sep 25, 2017 at 7:41 PM, Marko Rauhamaa wrote: >>> In Python, all expressions evaluate pointers. >> >> And that's an assertion that isn't backed by

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 2:52 AM, Tim Chase wrote: > On 2017-09-26 02:29, Steve D'Aprano wrote: >> x = Parrot(name="Polly") >> >> (using Python syntax for simplicity) and somebody tries to tell me >> that the value of x is anything but a Parrot instance named

Re: Call by binding [was Re: [Tutor] beginning to code]

On Tue, Sep 26, 2017 at 3:04 AM, Antoon Pardon wrote: > On 25-09-17 16:29, Marko Rauhamaa wrote: >> Antoon Pardon : >> >>> Op 25-09-17 om 15:16 schreef Marko Rauhamaa: No, I'm not. I'm talking about pointers in the abstract sense, both in

Re: [Tutor] beginning to code

On 25-09-17 15:37, Ned Batchelder wrote: > On 9/25/17 9:15 AM, Antoon Pardon wrote: >> Op 25-09-17 om 14:53 schreef Ned Batchelder: >>> On 9/25/17 8:24 AM, Steve D'Aprano wrote: On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: > Pass by reference doesn't imply being able to >

Re: Call by binding [was Re: [Tutor] beginning to code]

On 25-09-17 16:29, Marko Rauhamaa wrote: > Antoon Pardon : > >> Op 25-09-17 om 15:16 schreef Marko Rauhamaa: >>> No, I'm not. I'm talking about pointers in the abstract sense, both in >>> case of Python and Pascal. Neither language gives any hint as to the >>> physical

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 2017-09-26 02:29, Steve D'Aprano wrote: > x = Parrot(name="Polly") > > (using Python syntax for simplicity) and somebody tries to tell me > that the value of x is anything but a Parrot instance named "Polly", So this is a Polly-morphic constructor? -tkc --

calling __del__ [was Re: [Tutor] beginning to code]

On Sun, 24 Sep 2017 09:13 am, Bill wrote: [context snipped for brevity] > I agree (I was a bit hasty in my choice of words); but if they didn't > "have" these references, it would be difficult, though not impossible, > to refer to them. Also keep in mind that the garbage collector keeps >

Re: Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On 9/25/17 12:29 PM, Steve D'Aprano wrote: Regardless of whether I'm using Python, Swift, Java, C, Pascal or Scheme, if I write something like: x = Parrot(name="Polly") (using Python syntax for simplicity) and somebody tries to tell me that the value of x is anything but a Parrot instance

Grumpy-pants spoil-sport [was Re: [Tutor] beginning to code]

On Mon, 25 Sep 2017 10:53 pm, Ned Batchelder wrote: > Would we be able to end these interminable debates if we just agree that > we all know how it works, If only that were true. Not everyone understands Python semantics (or for that matter, Java/Swift/language of your choice) and I still come

Re: [Tutor] beginning to code

On 9/25/17 9:15 AM, Antoon Pardon wrote: Op 25-09-17 om 14:53 schreef Ned Batchelder: On 9/25/17 8:24 AM, Steve D'Aprano wrote: On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: Pass by reference doesn't imply being able to write a swap function. Really. Do you have a counter-example? A

Re: Call by binding [was Re: [Tutor] beginning to code]

Chris Angelico : > On Mon, Sep 25, 2017 at 7:41 PM, Marko Rauhamaa wrote: >> In Python, all expressions evaluate pointers. > > And that's an assertion that isn't backed by anything in the Python > specification. Where do you get that all Python expressions are

Re: Call by binding [was Re: [Tutor] beginning to code]

Antoon Pardon : > Op 25-09-17 om 15:16 schreef Marko Rauhamaa: >> No, I'm not. I'm talking about pointers in the abstract sense, both in >> case of Python and Pascal. Neither language gives any hint as to the >> physical nature of the pointer. > > Yes you are. Python doesn't

Re: Call by binding [was Re: [Tutor] beginning to code]

On Mon, Sep 25, 2017 at 7:41 PM, Marko Rauhamaa wrote: > Antoon Pardon : > >> the semantics of an assignment depends on the language > > I've only seen one kind of assignment in the general-purpose programming > languages I know, maybe with the exception of

Re: Call by binding [was Re: [Tutor] beginning to code]

Op 25-09-17 om 15:16 schreef Marko Rauhamaa: > Antoon Pardon : > >> Op 25-09-17 om 14:16 schreef Marko Rauhamaa: >>> Python only operates with pointers. You can operate with pointers in >>> Pascal as well. >> You are talking about implementation details. > No, I'm not. I'm

Re: Call by binding [was Re: [Tutor] beginning to code]

Antoon Pardon : > Op 25-09-17 om 14:16 schreef Marko Rauhamaa: >> Python only operates with pointers. You can operate with pointers in >> Pascal as well. > > You are talking about implementation details. No, I'm not. I'm talking about pointers in the abstract sense, both in

Re: [Tutor] beginning to code

Op 25-09-17 om 14:53 schreef Ned Batchelder: > On 9/25/17 8:24 AM, Steve D'Aprano wrote: >> On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: >> >>> Pass by reference doesn't imply being able to >>> write a swap function. >> Really. Do you have a counter-example? >> >> >>> A swap function as

Re: Call by binding [was Re: [Tutor] beginning to code]

Op 25-09-17 om 14:16 schreef Marko Rauhamaa: > Antoon Pardon : > >> Op 25-09-17 om 13:32 schreef Marko Rauhamaa: >>> In Python, assignment "mutates the target" as well. It's only that in >>> Python, the target is always a pointer. >> Fine if you want to word it like that, the

Re: [Tutor] beginning to code

On 9/25/17 8:24 AM, Steve D'Aprano wrote: On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: Pass by reference doesn't imply being able to write a swap function. Really. Do you have a counter-example? A swap function as possible in pascal requires two conditions. 1) Pass by reference 2)

Re: [Tutor] beginning to code

Op 25-09-17 om 14:24 schreef Steve D'Aprano: > On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: > >> Pass by reference doesn't imply being able to >> write a swap function. > Really. Do you have a counter-example? Python, smalltalk, scheme. > > >> A swap function as possible in pascal requires

Re: [Tutor] beginning to code

On Mon, 25 Sep 2017 08:05 pm, Antoon Pardon wrote: > Pass by reference doesn't imply being able to > write a swap function. Really. Do you have a counter-example? > A swap function as possible in pascal requires two conditions. > > 1) Pass by reference > 2) Copy-over assignment. I don't know

Re: Call by binding [was Re: [Tutor] beginning to code]

Antoon Pardon : > Op 25-09-17 om 13:32 schreef Marko Rauhamaa: >> In Python, assignment "mutates the target" as well. It's only that in >> Python, the target is always a pointer. > > Fine if you want to word it like that, the assignments in Pascal and > Python are still

Re: Call by binding [was Re: [Tutor] beginning to code]

Op 25-09-17 om 13:32 schreef Marko Rauhamaa: > Antoon Pardon : > >> Op 25-09-17 om 11:41 schreef Marko Rauhamaa: >>> Antoon Pardon : >>> the semantics of an assignment depends on the language >>> I've only seen one kind of assignment in the

Re: Call by binding [was Re: [Tutor] beginning to code]

Antoon Pardon : > Op 25-09-17 om 11:41 schreef Marko Rauhamaa: >> Antoon Pardon : >> >>> the semantics of an assignment depends on the language >> I've only seen one kind of assignment in the general-purpose >> programming languages I know,

Re: Call by binding [was Re: [Tutor] beginning to code]

Op 25-09-17 om 11:41 schreef Marko Rauhamaa: > Antoon Pardon : > >> the semantics of an assignment depends on the language > I've only seen one kind of assignment in the general-purpose programming > languages I know, maybe with the exception of Prolog and Rust. I disagree.

Re: [Tutor] beginning to code

Op 22-09-17 om 15:30 schreef Steve D'Aprano: > On Fri, 22 Sep 2017 10:27 pm, Marko Rauhamaa wrote: > >> r...@zedat.fu-berlin.de (Stefan Ram): >> >>> Marko Rauhamaa writes: swap(slot_ref(locals(), "x"), slot_ref(locals(), "y")) >>> You need to be able to write the call as

Re: Call by binding [was Re: [Tutor] beginning to code]

Antoon Pardon : > the semantics of an assignment depends on the language I've only seen one kind of assignment in the general-purpose programming languages I know, maybe with the exception of Prolog and Rust. So the assignment is the same everywhere, only the evaluation

Re: [Tutor] beginning to code

Op 24-09-17 om 04:13 schreef Steve D'Aprano: >> and consider >> that something else has to happen as an alternative, and (2) understand >> that in Python, objects don't have names, they have references (which >> have names). The rest could be "implementation dependent" (no?) > No. > > There are

Re: Call by binding [was Re: [Tutor] beginning to code]

Op 25-09-17 om 00:39 schreef Gregory Ewing: > Dennis Lee Bieber wrote: >> "Binding" itself tends to be Python specific terminology -- in >> that it >> is the parameter /name/ that gets bound/attached to the argument >> /object/. >> It is the same method as used in any Python "assignment"

Re: Call by binding [was Re: [Tutor] beginning to code]

Steve D'Aprano wrote: I think that suffers from the same problem as "call by binding" -- assignment is too general a word. If you're learning a new language, you're almost certainly going to learn how assignment works in that language before you get as far as worrying about parameter passing.

Re: Call by binding [was Re: [Tutor] beginning to code]

Dennis Lee Bieber wrote: Though "assignment" differs so much between languages That's the point of the term -- it's the same as whatever assignment does in the language concerned. This is true of *every* language I know of that uses the term "call by value" in its official

Re: Call by binding [was Re: [Tutor] beginning to code]

On Mon, 25 Sep 2017 08:39 am, Gregory Ewing wrote: > Dennis Lee Bieber wrote: >> "Binding" itself tends to be Python specific terminology -- in that it "Binding" is certainly not Python-specific: https://en.wikipedia.org/wiki/Name_binding and here's an example of the term in use:

Re: [Tutor] beginning to code

On Sun, 24 Sep 2017 12:37 pm, Bill wrote: >> For example, if I made "Pass-By-Reference Python" where all argument passing >> was done by reference, my language would differ from real Python: >> >> >> function(x, y) # allowed >> function(namespace.x, module.y) # allowed >> function(x + 1, 2) #

Re: Call by binding [was Re: [Tutor] beginning to code]

On Mon, 25 Sep 2017 01:56 am, bartc wrote: >> The point I am making is that we could describe just about any and all >> languages with functions "call by binding", whether they are call by value >> like C, call by reference like Fortran, call by need like Haskell, or call by >> sharing like

Re: Call by binding [was Re: [Tutor] beginning to code]

Dennis Lee Bieber wrote: "Binding" itself tends to be Python specific terminology -- in that it is the parameter /name/ that gets bound/attached to the argument /object/. It is the same method as used in any Python "assignment" statement, Which is why I think "call by assignment" would

Re: Call by binding [was Re: [Tutor] beginning to code]

On 24/09/2017 15:49, Steve D'Aprano wrote: On Mon, 25 Sep 2017 12:35 am, Stefan Ram wrote: WRT to assertions about Python, I try to base them on the "The Python Language Reference, Release 3.6.0" (PRL). So, WRT to parameter passing, I would use this part of the PRL: »The

Call by binding [was Re: [Tutor] beginning to code]

On Mon, 25 Sep 2017 12:35 am, Stefan Ram wrote: > WRT to assertions about Python, I try to base them on the > "The Python Language Reference, Release 3.6.0" (PRL). > > So, WRT to parameter passing, I would use this part of the PRL: > > »The following constructs bind names: formal

Re: [Tutor] beginning to code

Steve D'Aprano wrote: On Sun, 24 Sep 2017 08:18 am, Bill wrote: All one has to do, I think, is consider (1) that passing objects by "making copies" of them, would be prohibitively expensive Swift passes certain values (but not others!) by value and makes a copy. That includes many

Re: [Tutor] beginning to code

On Sun, 24 Sep 2017 08:18 am, Bill wrote: > All one has to do, I think, is consider (1) that passing objects by > "making copies" of them, would be prohibitively expensive Swift passes certain values (but not others!) by value and makes a copy. That includes many potentially large data types

Re: [Tutor] beginning to code

On Sun, 24 Sep 2017 07:03 am, ROGER GRAYDON CHRISTMAN wrote: > I usually do not encourage people to optimize correctness out of their code. +1 quote of the week :-) -- Steve “Cheer up,” they said, “things could be worse.” So I cheered up, and sure enough, things got worse. --

Re: [Tutor] beginning to code

Chris Angelico wrote: On Sun, Sep 24, 2017 at 8:18 AM, Bill wrote: Stephan Houben wrote: Op 2017-09-23, Rick Johnson schreef : These pissing contests over how values are passed in Python are totally irrelevant. What does it matter?

Re: [Tutor] beginning to code

Stephan Houben wrote: Op 2017-09-23, Rick Johnson schreef : These pissing contests over how values are passed in Python are totally irrelevant. What does it matter? Nothing will be gained or lost by arguing over which is true, or not. Unless the distinction is

Re: [Tutor] beginning to code

On Fri, Sep 22, 2017 12:03 PM, Dennis Lee Bier wrote:> On Fri, 22 Sep 2017 23:30:34 +1000, Steve D'Aprano > declaimed the following: > >The exercise is to demonstrate pass by reference semantics. That requires > >demonstrating the same

Re: [Tutor] beginning to code

Op 2017-09-23, Rick Johnson schreef : > These pissing contests over how values are passed in Python > are totally irrelevant. What does it matter? Nothing will be > gained or lost by arguing over which is true, or not. Unless > the distinction is preventing you from

Re: [Tutor] beginning to code

Mark Lawrence wrote: > [...] > I have no interest it what the C++ does, looks like or > anything else. All I'm bothered about is that two highly > respected members of the Python community have stated quite > clearly that Python is call by object. Many other people > have stated the same in this

Re: [Tutor] beginning to code

On 23/09/2017 04:06, Bill wrote: Mark Lawrence wrote: On 22/09/2017 08:01, Bill wrote: Steve D'Aprano wrote: On Fri, 22 Sep 2017 02:57 pm, Bill wrote: I find Python to be more more like Java, with regard to "passing objects by reference". Which is not a surprise, since both Python and Java

Re: [Tutor] beginning to code

Bill wrote: Mark Lawrence wrote: On 22/09/2017 08:01, Bill wrote: Steve D'Aprano wrote: On Fri, 22 Sep 2017 02:57 pm, Bill wrote: I find Python to be more more like Java, with regard to "passing objects by reference". Which is not a surprise, since both Python and Java use the same value

Re: [Tutor] beginning to code

Mark Lawrence wrote: On 22/09/2017 08:01, Bill wrote: Steve D'Aprano wrote: On Fri, 22 Sep 2017 02:57 pm, Bill wrote: I find Python to be more more like Java, with regard to "passing objects by reference". Which is not a surprise, since both Python and Java use the same value passing

Re: [Tutor] beginning to code

Chris Angelico : > On Fri, Sep 22, 2017 at 10:26 PM, Marko Rauhamaa wrote: >> Chris Angelico : >>> (Side point: Your slot_ref function is rather bizarre. It's a closure >>> AND a class, just in case one of them isn't sufficient. >> >> I don't

Re: [Tutor] beginning to code

On Fri, Sep 22, 2017 at 10:26 PM, Marko Rauhamaa wrote: > Chris Angelico : >> (Side point: Your slot_ref function is rather bizarre. It's a closure >> AND a class, just in case one of them isn't sufficient. > > I don't see anything bizarre in it at all. I use

Re: [Tutor] beginning to code

On Fri, 22 Sep 2017 10:27 pm, Marko Rauhamaa wrote: > r...@zedat.fu-berlin.de (Stefan Ram): > >> Marko Rauhamaa writes: >>>swap(slot_ref(locals(), "x"), slot_ref(locals(), "y")) >> >> You need to be able to write the call as >> >> swap( x, y ) > > Why? Because that's the

Re: [Tutor] beginning to code

On 22/09/2017 13:34, Steve D'Aprano wrote: On Fri, 22 Sep 2017 09:24 pm, Marko Rauhamaa wrote: Yes, following my recipe: def swap(ref_a, ref_b): a, b = ref_a.get(), ref_b.get() ref_a.set(b) ref_b.set(a) x = 10 y = "Z" swap(slot_ref(locals(), "x"),

Re: [Tutor] beginning to code

r...@zedat.fu-berlin.de (Stefan Ram): > Marko Rauhamaa writes: >>r...@zedat.fu-berlin.de (Stefan Ram): >>>Marko Rauhamaa writes: swap(slot_ref(locals(), "x"), slot_ref(locals(), "y")) >>>You need to be able to write the call as >>>swap( x, y ) >>Why? > >

Re: [Tutor] beginning to code

On Fri, 22 Sep 2017 09:24 pm, Marko Rauhamaa wrote: > bartc : > >> On 22/09/2017 10:23, Marko Rauhamaa wrote: >>> However, Python doesn't need any language changes to implement memory >>> slots. A memory slot could be defined as any object that implements >>> "get()" and

Re: [Tutor] beginning to code

r...@zedat.fu-berlin.de (Stefan Ram): > Marko Rauhamaa writes: >>swap(slot_ref(locals(), "x"), slot_ref(locals(), "y")) > > You need to be able to write the call as > > swap( x, y ) Why? Marko -- https://mail.python.org/mailman/listinfo/python-list

Re: [Tutor] beginning to code

Chris Angelico : > Sure, let me just put that into a function. CPython 3.7, although I'm > pretty sure most CPython versions will do the same, as will several of > the other Pythons. > [demonstration that it didn't work] Ok. The reason is this: Note: The contents of this

Re: [Tutor] beginning to code

On 22/09/2017 10:53, Bill wrote: I just wanted to mention that my comment was made in the context that Python is implemented by an interpreter written in C.   I realize that this may not always be the case.  However, I haven't heard anyone mention a Python interpreter written in Python yet.

  1   2   >