[protobuf] Re: Enum values are siblings of their type, not children of it.
https://github.com/google/protobuf/issues/1079
在 2010年8月21日星期六 UTC+8上午2:12:30，alopecoid写道：
>
> Hi,
>
> This post is about the fact that protobuf enum values use C++ scoping
> rules, meaning that, unlike in Java, enum values are siblings of their
> type, not children of it.
>
> Say I have the following contrived message:
>
> message MyMessage {
> enum Foo {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Foo foo = 1;
>
> enum Bar {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Bar bar = 2;
> }
>
> This wouldn't compile because the protobuf compiler recognizes the
> fact that for C++, the generated enum values for Foo and Bar would
> conflict with each other.
>
> However, for Java, this wouldn't be a problem. I would like to propose
> that instead of "punishing" the generated Java code because of C++'s
> strange enum behavior (by forcing developers to rename their enum
> values even though they don't collide), that instead, the generated C+
> + enum declarations are wrapped in their own nested namespaces? For
> example, something like:
>
> namespace Foo {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> namespace Bar {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> At this point, the enum values would be accessed like Foo::FIRST,
> Bar::FIRST, etc, which would eliminate the enum value collision
> problem altogether, and at the same time make them appear to behave
> more like Java's enum scoping rules (which arguably make more sense).
>
> Thoughts?
>
> Thank you.
--
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[protobuf] Re: Enum values are siblings of their type, not children of it.
Agree. It's a bad design to use old C++ scoping rules for enum values. Even
C++ itself has introduced enum class in C++11.
在 2015年11月10日星期二 UTC+8上午3:15:35，Teddy Zhang写道：
>
> Sorry to dig this old thread.
> I now one of the solution right now is to put the enum to different proto
> file and put them into different package. But that doesn't really work if
> the enums are under the same message.
>
> I would suggest add an option for c/c++, like below:
> enum Foo {
> option c_enum_prefix = "eFoo";
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
>
> And it will generate enum like below in c/c++:
> enum Foo {
> eFooFIRST = 0,
> eFooSECOND = 1,
> eFooBOTH = 2
> };
>
> This won't affect enum generation in managed language like java/c#, and it
> won't break backward compatibility (if the option is not specified,
> fallback to old behavior).
>
> Any comments?
>
> On Friday, August 20, 2010 at 11:12:30 AM UTC-7, alopecoid wrote:
>
>> Hi,
>>
>> This post is about the fact that protobuf enum values use C++ scoping
>> rules, meaning that, unlike in Java, enum values are siblings of their
>> type, not children of it.
>>
>> Say I have the following contrived message:
>>
>> message MyMessage {
>> enum Foo {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> required Foo foo = 1;
>>
>> enum Bar {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> required Bar bar = 2;
>> }
>>
>> This wouldn't compile because the protobuf compiler recognizes the
>> fact that for C++, the generated enum values for Foo and Bar would
>> conflict with each other.
>>
>> However, for Java, this wouldn't be a problem. I would like to propose
>> that instead of "punishing" the generated Java code because of C++'s
>> strange enum behavior (by forcing developers to rename their enum
>> values even though they don't collide), that instead, the generated C+
>> + enum declarations are wrapped in their own nested namespaces? For
>> example, something like:
>>
>> namespace Foo {
>> enum Enum {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> }
>>
>> namespace Bar {
>> enum Enum {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> }
>>
>> At this point, the enum values would be accessed like Foo::FIRST,
>> Bar::FIRST, etc, which would eliminate the enum value collision
>> problem altogether, and at the same time make them appear to behave
>> more like Java's enum scoping rules (which arguably make more sense).
>>
>> Thoughts?
>>
>> Thank you.
>
>
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[protobuf] Re: Enum values are siblings of their type, not children of it.
Sorry to dig this old thread.
I now one of the solution right now is to put the enum to different proto
file and put them into different package. But that doesn't really work if
the enums are under the same message.
I would suggest add an option for c/c++, like below:
enum Foo {
option c_enum_prefix = "eFoo";
FIRST = 0;
SECOND = 1;
BOTH = 2;
}
And it will generate enum like below in c/c++:
enum Foo {
eFooFIRST = 0,
eFooSECOND = 1,
eFooBOTH = 2
};
This won't affect enum generation in managed language like java/c#, and it
won't break backward compatibility (if the option is not specified,
fallback to old behavior).
Any comments?
On Friday, August 20, 2010 at 11:12:30 AM UTC-7, alopecoid wrote:
> Hi,
>
> This post is about the fact that protobuf enum values use C++ scoping
> rules, meaning that, unlike in Java, enum values are siblings of their
> type, not children of it.
>
> Say I have the following contrived message:
>
> message MyMessage {
> enum Foo {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Foo foo = 1;
>
> enum Bar {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Bar bar = 2;
> }
>
> This wouldn't compile because the protobuf compiler recognizes the
> fact that for C++, the generated enum values for Foo and Bar would
> conflict with each other.
>
> However, for Java, this wouldn't be a problem. I would like to propose
> that instead of "punishing" the generated Java code because of C++'s
> strange enum behavior (by forcing developers to rename their enum
> values even though they don't collide), that instead, the generated C+
> + enum declarations are wrapped in their own nested namespaces? For
> example, something like:
>
> namespace Foo {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> namespace Bar {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> At this point, the enum values would be accessed like Foo::FIRST,
> Bar::FIRST, etc, which would eliminate the enum value collision
> problem altogether, and at the same time make them appear to behave
> more like Java's enum scoping rules (which arguably make more sense).
>
> Thoughts?
>
> Thank you.
--
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[protobuf] Re: Enum values are siblings of their type, not children of it.
I don't think it's added in 2.4.1+. I don't see any related changes in
changelog.
On Friday, November 1, 2013 12:45:03 PM UTC-7, greg.mal...@gmail.com wrote:
>
> The solution is available in the latest version??? Please elaborate. I'm
> using 2.5.0 and I don't see it.
>
> -Greg
>
> On Tuesday, May 28, 2013 11:12:46 PM UTC-4, Giri Guntipalli wrote:
>>
>> Hi enum values conflict for C++ is there any solution now solution
>> suggested below is available in latest version any workarounds to handle
>> this problem with 2.4.1 or latert versions.
>>
>> Giri
>> On Friday, 20 August 2010 23:42:30 UTC+5:30, alopecoid wrote:
>>
>>> Hi,
>>>
>>> This post is about the fact that protobuf enum values use C++ scoping
>>> rules, meaning that, unlike in Java, enum values are siblings of their
>>> type, not children of it.
>>>
>>> Say I have the following contrived message:
>>>
>>> message MyMessage {
>>> enum Foo {
>>> FIRST = 0;
>>> SECOND = 1;
>>> BOTH = 2;
>>> }
>>> required Foo foo = 1;
>>>
>>> enum Bar {
>>> FIRST = 0;
>>> SECOND = 1;
>>> BOTH = 2;
>>> }
>>> required Bar bar = 2;
>>> }
>>>
>>> This wouldn't compile because the protobuf compiler recognizes the
>>> fact that for C++, the generated enum values for Foo and Bar would
>>> conflict with each other.
>>>
>>> However, for Java, this wouldn't be a problem. I would like to propose
>>> that instead of "punishing" the generated Java code because of C++'s
>>> strange enum behavior (by forcing developers to rename their enum
>>> values even though they don't collide), that instead, the generated C+
>>> + enum declarations are wrapped in their own nested namespaces? For
>>> example, something like:
>>>
>>> namespace Foo {
>>> enum Enum {
>>> FIRST = 0;
>>> SECOND = 1;
>>> BOTH = 2;
>>> }
>>> }
>>>
>>> namespace Bar {
>>> enum Enum {
>>> FIRST = 0;
>>> SECOND = 1;
>>> BOTH = 2;
>>> }
>>> }
>>>
>>> At this point, the enum values would be accessed like Foo::FIRST,
>>> Bar::FIRST, etc, which would eliminate the enum value collision
>>> problem altogether, and at the same time make them appear to behave
>>> more like Java's enum scoping rules (which arguably make more sense).
>>>
>>> Thoughts?
>>>
>>> Thank you.
>>
>>
--
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[protobuf] Re: Enum values are siblings of their type, not children of it.
The solution is available in the latest version??? Please elaborate. I'm
using 2.5.0 and I don't see it.
-Greg
On Tuesday, May 28, 2013 11:12:46 PM UTC-4, Giri Guntipalli wrote:
>
> Hi enum values conflict for C++ is there any solution now solution
> suggested below is available in latest version any workarounds to handle
> this problem with 2.4.1 or latert versions.
>
> Giri
> On Friday, 20 August 2010 23:42:30 UTC+5:30, alopecoid wrote:
>
>> Hi,
>>
>> This post is about the fact that protobuf enum values use C++ scoping
>> rules, meaning that, unlike in Java, enum values are siblings of their
>> type, not children of it.
>>
>> Say I have the following contrived message:
>>
>> message MyMessage {
>> enum Foo {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> required Foo foo = 1;
>>
>> enum Bar {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> required Bar bar = 2;
>> }
>>
>> This wouldn't compile because the protobuf compiler recognizes the
>> fact that for C++, the generated enum values for Foo and Bar would
>> conflict with each other.
>>
>> However, for Java, this wouldn't be a problem. I would like to propose
>> that instead of "punishing" the generated Java code because of C++'s
>> strange enum behavior (by forcing developers to rename their enum
>> values even though they don't collide), that instead, the generated C+
>> + enum declarations are wrapped in their own nested namespaces? For
>> example, something like:
>>
>> namespace Foo {
>> enum Enum {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> }
>>
>> namespace Bar {
>> enum Enum {
>> FIRST = 0;
>> SECOND = 1;
>> BOTH = 2;
>> }
>> }
>>
>> At this point, the enum values would be accessed like Foo::FIRST,
>> Bar::FIRST, etc, which would eliminate the enum value collision
>> problem altogether, and at the same time make them appear to behave
>> more like Java's enum scoping rules (which arguably make more sense).
>>
>> Thoughts?
>>
>> Thank you.
>
>
--
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[protobuf] Re: Enum values are siblings of their type, not children of it.
Hi enum values conflict for C++ is there any solution now solution
suggested below is available in latest version any workarounds to handle
this problem with 2.4.1 or latert versions.
Giri
On Friday, 20 August 2010 23:42:30 UTC+5:30, alopecoid wrote:
> Hi,
>
> This post is about the fact that protobuf enum values use C++ scoping
> rules, meaning that, unlike in Java, enum values are siblings of their
> type, not children of it.
>
> Say I have the following contrived message:
>
> message MyMessage {
> enum Foo {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Foo foo = 1;
>
> enum Bar {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Bar bar = 2;
> }
>
> This wouldn't compile because the protobuf compiler recognizes the
> fact that for C++, the generated enum values for Foo and Bar would
> conflict with each other.
>
> However, for Java, this wouldn't be a problem. I would like to propose
> that instead of "punishing" the generated Java code because of C++'s
> strange enum behavior (by forcing developers to rename their enum
> values even though they don't collide), that instead, the generated C+
> + enum declarations are wrapped in their own nested namespaces? For
> example, something like:
>
> namespace Foo {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> namespace Bar {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> At this point, the enum values would be accessed like Foo::FIRST,
> Bar::FIRST, etc, which would eliminate the enum value collision
> problem altogether, and at the same time make them appear to behave
> more like Java's enum scoping rules (which arguably make more sense).
>
> Thoughts?
>
> Thank you.
--
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[protobuf] Re: Enum values are siblings of their type, not children of it.
Another option is to use C++11 scoped enum syntax:
enum class Foo {
FIRST = 0;
SECOND=1;
}
and then generate scoped enums, which would look exactly like the snippet
above.
On Friday, August 20, 2010 1:12:30 PM UTC-5, alopecoid wrote:
>
> Hi,
>
> This post is about the fact that protobuf enum values use C++ scoping
> rules, meaning that, unlike in Java, enum values are siblings of their
> type, not children of it.
>
> Say I have the following contrived message:
>
> message MyMessage {
> enum Foo {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Foo foo = 1;
>
> enum Bar {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> required Bar bar = 2;
> }
>
> This wouldn't compile because the protobuf compiler recognizes the
> fact that for C++, the generated enum values for Foo and Bar would
> conflict with each other.
>
> However, for Java, this wouldn't be a problem. I would like to propose
> that instead of "punishing" the generated Java code because of C++'s
> strange enum behavior (by forcing developers to rename their enum
> values even though they don't collide), that instead, the generated C+
> + enum declarations are wrapped in their own nested namespaces? For
> example, something like:
>
> namespace Foo {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> namespace Bar {
> enum Enum {
> FIRST = 0;
> SECOND = 1;
> BOTH = 2;
> }
> }
>
> At this point, the enum values would be accessed like Foo::FIRST,
> Bar::FIRST, etc, which would eliminate the enum value collision
> problem altogether, and at the same time make them appear to behave
> more like Java's enum scoping rules (which arguably make more sense).
>
> Thoughts?
>
> Thank you.
--
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