Re: [go-nuts] How to fix an awful marshal reflection hack

[burak serdar]

On Thu, Dec 1, 2022 at 6:39 AM 'Mark' via golang-nuts <
golang-nuts@googlegroups.com> wrote:

> The reason there's no nullable in the real code is that it isn't needed
> there: if the field is to a pointer variable (e.g., *string), then I call
> hack() and that adds the '?' to the string so no need for a nullable bool;
> otherwise for non-pointers it falls through to the normal processing. So
> the complete -- and working -- code is in the repo and go test works. But
> replacing the call to hack() with kind = field.Type().Elem().Kind() breaks
> the tests.
>


Your original code set the nullable to true in the if-block. Do you still
have that piece?


>
> On Thursday, December 1, 2022 at 1:09:50 PM UTC Marvin Renich wrote:
>
>> * 'Mark' via golang-nuts  [221201 05:17]:
>> > I tried that and it works in the playground, and I added more types and
>> it
>> > still works in the playground .
>> > But in my program it still doesn't work:-(
>> > The actual code is here tdb-go <
>> https://github.com/mark-summerfield/tdb-go>
>> > in the file marshal.go from line 133 function marshalTableMetaData().
>> > If you run: go test it all works; but if you replace the call to hack()
>> and
>> > use nullable as you did in the playground, some of the tests fail.
>>
>> You don't show the code that doesn't work (i.e. with nullable). Did you
>> make a typo like you did in your code below?
>>
>> > On Thursday, December 1, 2022 at 9:45:48 AM UTC kortschak wrote:
>> >
>> > > On Thu, 2022-12-01 at 00:33 -0800, 'Mark' via golang-nuts wrote:
>> > > > Thanks. I've now tried that as follows:
>> > > >
>> > > > fmt.Printf("@@: %T %v\n", field, field)
>> > > > kind = field.Type().Elem().Kind()
>> > > > fmt.Printf("##: %T %v\n", field, field)
>>
>> Note that in both Printf statements, you are using field rather than
>> kind. If the two Printf's gave different results, I would consider it a
>> compiler bug (a really egregious one!).
>>
>> > > > In every case the output for kind before and after was identical.
>> > > > (Naturally, I tried without the print statements too.) And, of
>> course
>> > > > the tests fail. So I'm _still_ using the awful hack!
>> > > >
>> > >
>> > > Doesn't this do what you want?
>> > >
>> > > https://go.dev/play/p/7jUw_iW8B_8
>>
>> ...Marvin
>>
>> --
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Re: [go-nuts] How to fix an awful marshal reflection hack

['Mark' via golang-nuts]

The reason there's no nullable in the real code is that it isn't needed 
there: if the field is to a pointer variable (e.g., *string), then I call 
hack() and that adds the '?' to the string so no need for a nullable bool; 
otherwise for non-pointers it falls through to the normal processing. So 
the complete -- and working -- code is in the repo and go test works. But 
replacing the call to hack() with kind = field.Type().Elem().Kind() breaks 
the tests.

On Thursday, December 1, 2022 at 1:09:50 PM UTC Marvin Renich wrote:

> * 'Mark' via golang-nuts  [221201 05:17]:
> > I tried that and it works in the playground, and I added more types and 
> it 
> > still works in the playground .
> > But in my program it still doesn't work:-( 
> > The actual code is here tdb-go <
> https://github.com/mark-summerfield/tdb-go> 
> > in the file marshal.go from line 133 function marshalTableMetaData().
> > If you run: go test it all works; but if you replace the call to hack() 
> and 
> > use nullable as you did in the playground, some of the tests fail.
>
> You don't show the code that doesn't work (i.e. with nullable). Did you
> make a typo like you did in your code below?
>
> > On Thursday, December 1, 2022 at 9:45:48 AM UTC kortschak wrote:
> > 
> > > On Thu, 2022-12-01 at 00:33 -0800, 'Mark' via golang-nuts wrote:
> > > > Thanks. I've now tried that as follows:
> > > >
> > > > fmt.Printf("@@: %T %v\n", field, field)
> > > > kind = field.Type().Elem().Kind()
> > > > fmt.Printf("##: %T %v\n", field, field)
>
> Note that in both Printf statements, you are using field rather than
> kind. If the two Printf's gave different results, I would consider it a
> compiler bug (a really egregious one!).
>
> > > > In every case the output for kind before and after was identical.
> > > > (Naturally, I tried without the print statements too.) And, of course
> > > > the tests fail. So I'm _still_ using the awful hack!
> > > >
> > >
> > > Doesn't this do what you want?
> > >
> > > https://go.dev/play/p/7jUw_iW8B_8
>
> ...Marvin
>
>

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Re: [go-nuts] How to fix an awful marshal reflection hack

[Marvin Renich]

* 'Mark' via golang-nuts  [221201 05:17]:
> I tried that and it works in the playground, and I added more types and it 
> still works in the playground .
> But in my program it still doesn't work:-( 
> The actual code is here tdb-go  
> in the file marshal.go from line 133 function marshalTableMetaData().
> If you run: go test it all works; but if you replace the call to hack() and 
> use nullable as you did in the playground, some of the tests fail.

You don't show the code that doesn't work (i.e. with nullable).  Did you
make a typo like you did in your code below?

> On Thursday, December 1, 2022 at 9:45:48 AM UTC kortschak wrote:
> 
> > On Thu, 2022-12-01 at 00:33 -0800, 'Mark' via golang-nuts wrote:
> > > Thanks. I've now tried that as follows:
> > >
> > > fmt.Printf("@@: %T %v\n", field, field)
> > > kind = field.Type().Elem().Kind()
> > > fmt.Printf("##: %T %v\n", field, field)

Note that in both Printf statements, you are using field rather than
kind.  If the two Printf's gave different results, I would consider it a
compiler bug (a really egregious one!).

> > > In every case the output for kind before and after was identical.
> > > (Naturally, I tried without the print statements too.) And, of course
> > > the tests fail. So I'm _still_ using the awful hack!
> > >
> >
> > Doesn't this do what you want?
> >
> > https://go.dev/play/p/7jUw_iW8B_8

...Marvin

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Re: [go-nuts] How to fix an awful marshal reflection hack

['Mark' via golang-nuts]

I tried that and it works in the playground, and I added more types and it 
still works in the playground .
But in my program it still doesn't work:-( 
The actual code is here tdb-go  
in the file marshal.go from line 133 function marshalTableMetaData().
If you run: go test it all works; but if you replace the call to hack() and 
use nullable as you did in the playground, some of the tests fail.

On Thursday, December 1, 2022 at 9:45:48 AM UTC kortschak wrote:

> On Thu, 2022-12-01 at 00:33 -0800, 'Mark' via golang-nuts wrote:
> > Thanks. I've now tried that as follows:
> >
> > fmt.Printf("@@: %T %v\n", field, field)
> > kind = field.Type().Elem().Kind()
> > fmt.Printf("##: %T %v\n", field, field)
> >
> > In every case the output for kind before and after was identical.
> > (Naturally, I tried without the print statements too.) And, of course
> > the tests fail. So I'm _still_ using the awful hack!
> >
>
> Doesn't this do what you want?
>
> https://go.dev/play/p/7jUw_iW8B_8
>
>

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Re: [go-nuts] How to fix an awful marshal reflection hack

['Dan Kortschak' via golang-nuts]

On Thu, 2022-12-01 at 00:33 -0800, 'Mark' via golang-nuts wrote:
> Thanks. I've now tried that as follows:
>
>         fmt.Printf("@@: %T %v\n", field, field)
>         kind = field.Type().Elem().Kind()
>         fmt.Printf("##: %T %v\n", field, field)
>
> In every case the output for kind before and after was identical.
> (Naturally, I tried without the print statements too.) And, of course
> the tests fail. So I'm _still_ using the awful hack!
>

Doesn't this do what you want?

https://go.dev/play/p/7jUw_iW8B_8

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Re: [go-nuts] How to fix an awful marshal reflection hack

['Mark' via golang-nuts]

Thanks. I've now tried that as follows:

fmt.Printf("@@: %T %v\n", field, field)
kind = field.Type().Elem().Kind()
fmt.Printf("##: %T %v\n", field, field)

In every case the output for kind before and after was identical. 
(Naturally, I tried without the print statements too.) And, of course the 
tests fail. So I'm _still_ using the awful hack!

On Wednesday, November 30, 2022 at 5:30:24 PM UTC bse...@computer.org wrote:

> On Wed, Nov 30, 2022 at 10:17 AM 'Mark' via golang-nuts <
> golan...@googlegroups.com> wrote:
>
>> Yes, I'd already tried that (that's what I started with) and 
>> unfortunately it doesn't work.
>>
>
> It fails if field.Elem() is nil. Try this:
>
>   kind = field.Type().Elem().Kind()
>  
>
>>
>> On Wednesday, November 30, 2022 at 3:37:47 PM UTC bse...@computer.org 
>> wrote:
>>
>>> On Wed, Nov 30, 2022 at 5:29 AM 'Mark' via golang-nuts <
>>> golan...@googlegroups.com> wrote:
>>>
 I have this code which works but has a horrible hack:
 ...
 nullable := false
 kind := field.Kind() // field's type is reflect.Value
 if kind == reflect.Ptr {

>>>
>>> This should work:
>>>
>>> kind = field.Elem().Kind()
>>>
>>>
>>>  
>>>
 // FIXME How can I improve upon this truly awful hack?
 switch field.Type().String() {
 case "*int", "*int8", "*uint8", "*int16", "*uint16", "*int32", 
 "*uint32", "*int64", "*uint64":
 kind = reflect.Int
 case "*float32", "*float64":
 kind = reflect.Float64
 }
 nullable = true
 }
 switch kind {
 case reflect.Bool:
 out.WriteString("bool")
 case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, 
 reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, 
 reflect.Uint32, 
 reflect.Uint64:
 out.WriteString("int")
 case reflect.Float32, reflect.Float64:
 out.WriteString("real")
 ...
 if nullable {
 out.WriteByte('?')
 }
 What is the correct way to achieve what I'm aiming for?

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 .

>>> -- 
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>>  
>> 
>> .
>>
>

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Re: [go-nuts] How to fix an awful marshal reflection hack

[burak serdar]

On Wed, Nov 30, 2022 at 10:17 AM 'Mark' via golang-nuts <
golang-nuts@googlegroups.com> wrote:

> Yes, I'd already tried that (that's what I started with) and unfortunately
> it doesn't work.
>

It fails if field.Elem() is nil. Try this:

  kind = field.Type().Elem().Kind()


>
> On Wednesday, November 30, 2022 at 3:37:47 PM UTC bse...@computer.org
> wrote:
>
>> On Wed, Nov 30, 2022 at 5:29 AM 'Mark' via golang-nuts <
>> golan...@googlegroups.com> wrote:
>>
>>> I have this code which works but has a horrible hack:
>>> ...
>>> nullable := false
>>> kind := field.Kind() // field's type is reflect.Value
>>> if kind == reflect.Ptr {
>>>
>>
>> This should work:
>>
>> kind = field.Elem().Kind()
>>
>>
>>
>>
>>> // FIXME How can I improve upon this truly awful hack?
>>> switch field.Type().String() {
>>> case "*int", "*int8", "*uint8", "*int16", "*uint16", "*int32",
>>> "*uint32", "*int64", "*uint64":
>>> kind = reflect.Int
>>> case "*float32", "*float64":
>>> kind = reflect.Float64
>>> }
>>> nullable = true
>>> }
>>> switch kind {
>>> case reflect.Bool:
>>> out.WriteString("bool")
>>> case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
>>> reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
>>> reflect.Uint64:
>>> out.WriteString("int")
>>> case reflect.Float32, reflect.Float64:
>>> out.WriteString("real")
>>> ...
>>> if nullable {
>>> out.WriteByte('?')
>>> }
>>> What is the correct way to achieve what I'm aiming for?
>>>
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "golang-nuts" group.
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>>> an email to golang-nuts...@googlegroups.com.
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>>> 
>>> .
>>>
>> --
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Re: [go-nuts] How to fix an awful marshal reflection hack

['Mark' via golang-nuts]

Yes, I'd already tried that (that's what I started with) and unfortunately 
it doesn't work.

On Wednesday, November 30, 2022 at 3:37:47 PM UTC bse...@computer.org wrote:

> On Wed, Nov 30, 2022 at 5:29 AM 'Mark' via golang-nuts <
> golan...@googlegroups.com> wrote:
>
>> I have this code which works but has a horrible hack:
>> ...
>> nullable := false
>> kind := field.Kind() // field's type is reflect.Value
>> if kind == reflect.Ptr {
>>
>
> This should work:
>
> kind = field.Elem().Kind()
>
>
>  
>
>> // FIXME How can I improve upon this truly awful hack?
>> switch field.Type().String() {
>> case "*int", "*int8", "*uint8", "*int16", "*uint16", "*int32", 
>> "*uint32", "*int64", "*uint64":
>> kind = reflect.Int
>> case "*float32", "*float64":
>> kind = reflect.Float64
>> }
>> nullable = true
>> }
>> switch kind {
>> case reflect.Bool:
>> out.WriteString("bool")
>> case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, 
>> reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, 
>> reflect.Uint64:
>> out.WriteString("int")
>> case reflect.Float32, reflect.Float64:
>> out.WriteString("real")
>> ...
>> if nullable {
>> out.WriteByte('?')
>> }
>> What is the correct way to achieve what I'm aiming for?
>>
>> -- 
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>> "golang-nuts" group.
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>>  
>> 
>> .
>>
>

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Re: [go-nuts] How to fix an awful marshal reflection hack

[burak serdar]

On Wed, Nov 30, 2022 at 5:29 AM 'Mark' via golang-nuts <
golang-nuts@googlegroups.com> wrote:

> I have this code which works but has a horrible hack:
> ...
> nullable := false
> kind := field.Kind() // field's type is reflect.Value
> if kind == reflect.Ptr {
>

This should work:

kind = field.Elem().Kind()




> // FIXME How can I improve upon this truly awful hack?
> switch field.Type().String() {
> case "*int", "*int8", "*uint8", "*int16", "*uint16", "*int32",
> "*uint32", "*int64", "*uint64":
> kind = reflect.Int
> case "*float32", "*float64":
> kind = reflect.Float64
> }
> nullable = true
> }
> switch kind {
> case reflect.Bool:
> out.WriteString("bool")
> case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
> reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
> reflect.Uint64:
> out.WriteString("int")
> case reflect.Float32, reflect.Float64:
> out.WriteString("real")
> ...
> if nullable {
> out.WriteByte('?')
> }
> What is the correct way to achieve what I'm aiming for?
>
> --
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> 
> .
>

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[go-nuts] How to fix an awful marshal reflection hack

['Mark' via golang-nuts]

I have this code which works but has a horrible hack:
...
nullable := false
kind := field.Kind() // field's type is reflect.Value
if kind == reflect.Ptr {
// FIXME How can I improve upon this truly awful hack?
switch field.Type().String() {
case "*int", "*int8", "*uint8", "*int16", "*uint16", "*int32", 
"*uint32", "*int64", "*uint64":
kind = reflect.Int
case "*float32", "*float64":
kind = reflect.Float64
}
nullable = true
}
switch kind {
case reflect.Bool:
out.WriteString("bool")
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, 
reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, 
reflect.Uint64:
out.WriteString("int")
case reflect.Float32, reflect.Float64:
out.WriteString("real")
...
if nullable {
out.WriteByte('?')
}
What is the correct way to achieve what I'm aiming for?

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