On Friday, 13 January 2017 11:26:29 UTC+2, hui zhang wrote:
>
> thank u very much. I know they all have work around. and I also write
> some util my own.
> I just wish go to make it more simpler, wish the code could be clean and
> short .
> Right now go let programer do repeat and Mechanical work
>
> the top 3 are bothering me most
> [1],[2] let me do many type cast all the time.
> [3] let me have to do initialize default for each struct.
> right now I am solving [3] like this.
> type F struct {x int32}
> var FDefault = F{x:1}
> type E struct {f F}
> var EDefault = E{f: FDefault}
> type D struct {e E}
> var DDefault = D{e: EDefault}
>
>
What is the actual code that you are working on? I doubt you have structs
named F, E, D.
It's very hard to suggest a better model for "something" without knowing
what that "something" is.
+ Egon
>
>
> 在 2017年1月13日星期五 UTC+8下午4:39:55，Egon写道：
>>
>> As Shawn mentioned, most of these were decided against for varying
>> reasons. I'll try to give as much info as I can remember.
>>
>> On Friday, 13 January 2017 09:44:10 UTC+2, hui zhang wrote:
>>>
>>> Disadvantage of Go
>>> 1 No Generic For Now
>>>
>> That make user coding repeat code many times, even for basic type such as
>>> int float bool
>>> It is not easy , even to make a generic min function.
>>>
>> using interface will always check type casting.
>>> and for []interface{} in generic function, u can't do cast
>>>
>>
>> You cannot cast []interface{} to []float64 because they have different
>> memory layouts.
>>
>>
>>>
>>> 2 Incomplete Type in Basic Lib
>>> Take math lib as an example, math.Max math.Min are only for float64 ,
>>> you have do stupid conversion for other type.
>>>
>>
>>> 3 No Default Value for struct.
>>> Consider multilayer struct. A {B {C {D {E {F} } } }
>>> to init A to a default value will be complicated.
>>> And how about A[] slice
>>> And what if D E F are from third party lib ?
>>> You have to dig into 3rd party code just for its default value.
>>> For It may have none zero default value.
>>>
>>
>> All structs are zero initialized.
>>
>> If you had default-values for structs the overhead of constructing
>> something becomes non-obvious.
>>
>>
>>>
>>> 4 Can not Cycle import.
>>> package A B can not import each other at the same time.
>>> While other language can.
>>> It seems not a big deal just put the the common thing in a new package
>>> But when the package and project grow bigger, it just easy to say.
>>> This change will affect all caller.
>>>
>>
>> Structures that have cyclic dependencies have longer compile times, init
>> order becomes more confusing and prone for errors, and a program having
>> cyclic imports is harder to understand than one without it (usually).
>>
>> Break cycles with DI.
>>
>>
>>> 5 Inconsistent type conversion
>>> bool type are normal type just like int and float ,
>>> but u can't do below. while other type can cast to others
>>> int(bool) bool(int)
>>>
>>>
>> https://github.com/golang/go/issues/9367#issuecomment-143128337
>>
>>
>>> 6 No multi casting expression
>>> func foo() (int16, int8)
>>> var i,j int32 = (int32,int32)(foo())
>>> Since go can't do this, why go provide multi return value.
>>>
>>
>> Why would you not return int32 immediately from `foo`?
>> Why would you write `foo` in the first place?
>>
>> 7 No Ternary Expression
>>> hardly find a language without it except go
>>>
>>
>>> 8 No Negative Index for slice
>>> all other script language support a[-1] as a[len(a)-1]
>>>
>>
>> In such situations, indexing that involves computation (e.g. `a[n-5]`)
>> can easily hide mistakes.
>>
>>
>>>
>>> When programing in go
>>> we have to do repeated type casting many times, due to the above.
>>> write long code for Ternary ,int(bool) a[-1] etc
>>>
>>
>> If you repeatedly need to use it, then:
>>
>> func ifthen(v bool, a, b int) { if v { return a; }; return b }
>> func asint(v bool) int { return ifthen(v, 1, 0) }
>>
>> x := ifthen(a < b, a, b)
>>
>> init big struct with default value.
>>> Which make Go not an Elegant and simple language.
>>> Once I thought go was a simple language,
>>> but in fact we write more code.
>>>
>>> All above are proposal for many times.
>>> And it is 6 years(or more).
>>> These basic functions are still not added. some of that should be add in
>>> version 1.0
>>> I belive most above could make go simpler,
>>> someone know a little programing could know how to use it.
>>> however someone still fear it make go complicate like c++
>>>
>>
>> But, it seems to me you are trying to use Go as a language that it is
>> not. Can you show the code where you are having problems with some/all of
>> these points, then we can discuss how to avoid these situations in the
>> first place.
>>
>> If you try to use any language in a way that it was meant to, you will
>> have problems.
>>
>> + Egon
>>
>
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