On Sat, Jun 3, 2023 at 1:40 PM peterGo <go.peter...@gmail.com> wrote:
>
> Kamil Ziemian,
>
> // list of prime numbers
> primes := []int{2, 3, 5, 7, 9, 2147483647}
>
> The variable prime is a list of some prime numbers starting with the
> lowest and ending with the highest prime numbers that can safely be
> represented an int. An int may either 32 or 64 bits.
>
> Please explain the joke.
>
Could it be that 9 is not prime?
>
>
> Note: “Explaining a joke is like dissecting a frog. You understand it
> better but the frog dies in the process.”
> ― E.B. White
>
> peter
> On Saturday, June 3, 2023 at 3:13:28 PM UTC-4 Kamil Ziemian wrote:
>
>> Is this example found in the "Composite literals" section of Go Spec a
>> joke?
>> // list of prime numbers
>> primes := []int{2, 3, 5, 7, 9, 2147483647 <(214)%20748-3647>}
>>
>> I checked on the internet and 2147483647 <(214)%20748-3647> is a prime
>> number (https://en.wikipedia.org/wiki/2,147,483,647), so this element is
>> fine.
>>
>> Best regards
>> Kamil
>>
>> czwartek, 4 maja 2023 o 16:38:50 UTC+2 Kamil Ziemian napisał(a):
>>
>>> You convince me to your point Axel Wagner. At the same time if we look
>>> at examples in Go Spec, I think their can be improved.
>>> "A0, A1, and []string
>>> A2 and struct{ a, b int }
>>> A3 and int A4, func(int, float64) *[]string, and A5
>>>
>>> B0 and C0
>>> D0[int, string] and E0
>>> []int and []int
>>> struct{ a, b *B5 } and struct{ a, b *B5 }
>>> func(x int, y float64) *[]string, func(int, float64) (result *[]string),
>>> and A5"
>>> I mean, first we need to check that A0, A1 and []string are the same
>>> type and after few examples like D0[int, string] is the same as E0, we have
>>> stated []int and []int are the same type. If you convince yourself that A0
>>> is the same as A1 and both are the same as []string, checking that []int
>>> has the same type as []int is quite trivial. I would prefer that examples
>>> would start from basic cases like []int is []int and []A3 is []int (if this
>>> one is true) and progress to more convoluted like D0[int, string] is E0.
>>>
>>> Best regards,
>>> Kamil
>>>
>>> czwartek, 4 maja 2023 o 14:12:25 UTC+2 Axel Wagner napisał(a):
>>>
>>>> Personally, I'd rather add more examples of "self-evidently equal
>>>> types". In my opinion, all the type aliases in that block confuse matters
>>>> quite a bit.
>>>>
>>>> "[]int and []int are identical" is not actually self-evident at all. It
>>>> is self-evident that any sensible definition of type identity *should* make
>>>> them identical. But it's not self-evident that the given definition *does*.
>>>> Spelling that out in the example, means you are nudged to look at the
>>>> definition and see how their identity follows (by finding "Two slice types
>>>> are identical if they have identical element types").
>>>>
>>>> In fact, whenever you define an equivalence relation, proving that it
>>>> is reflexive is the very first step. And it's not always trivial. For
>>>> example, `==` on `float64` is *not* reflexive. It seems obvious that NaN ==
>>>> NaN *should* hold from how it's spelled - but it doesn't.
>>>>
>>>> So, I disagree that the examples should limit themselves to cases where
>>>> it's non-obvious that the two types should be identical.
>>>>
>>>> On Thu, May 4, 2023 at 12:35 PM Kamil Ziemian <kziem...@gmail.com>
>>>> wrote:
>>>>
>>>>> There is a second such example just below "[]int and []int", but to
>>>>> understand it we need some more type declarations, I listed them below.
>>>>> `type (
>>>>> A0 = []string
>>>>> A1 = A0
>>>>> A2 = struct{ a, b int }
>>>>> A3 = int
>>>>> A4 = func(A3, float64) *A0
>>>>> A5 = func(x int, _ float64) *[]string
>>>>>
>>>>> B0 A0
>>>>> B1 []string
>>>>> B2 struct{ a, b int }
>>>>> B3 struct{ a, c int }
>>>>> B4 func(int, float64) *B0
>>>>> B5 func(x int, y float64) *A1
>>>>>
>>>>> // Unimportant part.
>>>>> )`
>>>>> The line in question is
>>>>> "struct{ a, b *B5 } and struct{ a, b *B5 }"
>>>>> which is true, but again feel out of place. I only start grasping
>>>>> rules of types identity, but I make guess that it should be something like
>>>>> "struct{ a, b *A5 } and struct{ a, b *B5 }"
>>>>>
>>>>> Of course it my just be that I'm just stupid. Feel free to inform me
>>>>> that indeed I have no idea what is going on in the Go Spec.
>>>>>
>>>>> Best regards,
>>>>> Kamil
>>>>> czwartek, 4 maja 2023 o 12:20:35 UTC+2 Kamil Ziemian napisał(a):
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> In the section "Type identity" of Go Spec we read a list of type
>>>>>> declarations
>>>>>> `type (
>>>>>> A0 = []string
>>>>>> A1 = A0
>>>>>> A2 = struct{ a, b int }
>>>>>> A3 = int
>>>>>> A4 = func(A3, float64) *A0
>>>>>> A5 = func(x int, _ float64) *[]string
>>>>>>
>>>>>> // Part unimportant for my point.
>>>>>> )`
>>>>>> and then we have list of types that are identical. Among them we can
>>>>>> find text
>>>>>> "[]int and []int"
>>>>>> It is obviously true, but feel out of place. I make a humble guess
>>>>>> that authors intended something along the lines
>>>>>> "[]A3 and []int"
>>>>>> Can someone look at this part of Go Spec? I feel that someone make a
>>>>>> mistake, but at the same time humble me saying that there is any mistake
>>>>>> in
>>>>>> the Go Spec is something that I shouldn't do.
>>>>>>
>>>>>> Best regards,
>>>>>> Kamil
>>>>>> poniedziałek, 8 listopada 2021 o 10:59:23 UTC+1 Kamil Ziemian
>>>>>> napisał(a):
>>>>>>
>>>>>>> Thank you Jan Mercl, now I start to understand this rule.
>>>>>>>
>>>>>>> Best
>>>>>>> Kamil
>>>>>>>
>>>>>>> niedziela, 7 listopada 2021 o 19:34:41 UTC+1 Jan Mercl napisał(a):
>>>>>>>
>>>>>>>> On Sun, Nov 7, 2021 at 7:23 PM Kamil Ziemian <kziem...@gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>> > Can anyone give me explicit example when semicolon is omitted in
>>>>>>>> accordance to the second rule and explanation where it should be? I
>>>>>>>> probably see such situations dozens of times, I just not know that they
>>>>>>>> would needed semicolon in some places.
>>>>>>>>
>>>>>>>> I think this is a simple example:
>>>>>>>> https://play.golang.org/p/ZfKxTos6GjY
>>>>>>>>
>>>>>>>> Click "Run" to see the code is valid, then "Format" to watch one
>>>>>>>> semicolon disappear and then "Run" again to see it's still valid
>>>>>>>> code.
>>>>>>>>
>>>>>>> --
>>>>>
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>>>>> .
>>>>>
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