Re: [capnproto] Dynamically reading schema const property at runtime (c++)
Appreciate the reply Kenton, that got me to the solution I was looking for:
std::string type =
person_schema->getNested("type").asConst().as().cStr();
And will do on avoiding kj::_. Thanks again!
On Wednesday, June 8, 2022 at 11:13:56 AM UTC-7 ken...@cloudflare.com wrote:
> Hi Daniel,
>
> I think you can do:
>
> capnp::ConstSchema type =
> schema.getNested("Person").getNested("type").asConst();
>
> But it's been a long time since I touched this.
>
> By the way, please do not use stuff in kj::_ directly, that is a private
> namespace. To read a Maybe, use KJ_IF_MAYBE, KJ_ASSERT_NONNULL,
> KJ_UNWRAP_OR, etc.
>
> -Kenton
>
> On Wed, Jun 8, 2022 at 12:33 PM Daniel Koohmarey <
> daniel.k...@braincorp.com> wrote:
>
>> Given the following dummy schema test.capnp:
>> struct Person {
>>const type :Text = "person.type.example";
>>version @0 :UInt32;
>>name @1 :Text;
>> }
>>
>> At runtime, how can we read the default const value from a schema struct
>> (i.e the "person.type.example" above? (type is not considered a field
>> within the struct, but it does appear as a node in the proto):
>> std::string schema_filename = "test.capnp"; kj::ArrayPtr> kj::StringPtr> import_paths;
>> capnp::SchemaParser parser;
>> capnp::ParsedSchema schema = parser.parseDiskFile(
>> schema_filename.c_str(),
>>
>> schema_filename.c_str(), import_paths);
>> auto person_maybe = schema.findNested("Person");
>> auto* person_schema = kj::_::readMaybe(person_maybe);
>>
>> // how can I read "person.type.example" out of the Person struct?
>>
>> Any guidance on the matter is appreciated, thanks!
>>
>> --
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>> "Cap'n Proto" group.
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>>
>>
>> .
>>
>
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Re: [capnproto] Dynamically reading schema const property at runtime (c++)
Hi Daniel,
I think you can do:
capnp::ConstSchema type =
schema.getNested("Person").getNested("type").asConst();
But it's been a long time since I touched this.
By the way, please do not use stuff in kj::_ directly, that is a private
namespace. To read a Maybe, use KJ_IF_MAYBE, KJ_ASSERT_NONNULL,
KJ_UNWRAP_OR, etc.
-Kenton
On Wed, Jun 8, 2022 at 12:33 PM Daniel Koohmarey <
daniel.koohma...@braincorp.com> wrote:
> Given the following dummy schema test.capnp:
> struct Person {
>const type :Text = "person.type.example";
>version @0 :UInt32;
>name @1 :Text;
> }
>
> At runtime, how can we read the default const value from a schema struct
> (i.e the "person.type.example" above? (type is not considered a field
> within the struct, but it does appear as a node in the proto):
> std::string schema_filename = "test.capnp"; kj::ArrayPtr kj::StringPtr> import_paths;
> capnp::SchemaParser parser;
> capnp::ParsedSchema schema = parser.parseDiskFile(
> schema_filename.c_str(),
>
> schema_filename.c_str(), import_paths);
> auto person_maybe = schema.findNested("Person");
> auto* person_schema = kj::_::readMaybe(person_maybe);
>
> // how can I read "person.type.example" out of the Person struct?
>
> Any guidance on the matter is appreciated, thanks!
>
> --
> You received this message because you are subscribed to the Google Groups
> "Cap'n Proto" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to capnproto+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/capnproto/389bc2ea-3279-4ddc-b8cc-f554d636767fn%40googlegroups.com
>
> .
>
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[capnproto] Dynamically reading schema const property at runtime (c++)
Given the following dummy schema test.capnp:
struct Person {
const type :Text = "person.type.example";
version @0 :UInt32;
name @1 :Text;
}
At runtime, how can we read the default const value from a schema struct
(i.e the "person.type.example" above? (type is not considered a field
within the struct, but it does appear as a node in the proto):
std::string schema_filename = "test.capnp"; kj::ArrayPtr import_paths;
capnp::SchemaParser parser;
capnp::ParsedSchema schema = parser.parseDiskFile( schema_filename.c_str(),
schema_filename.c_str(), import_paths);
auto person_maybe = schema.findNested("Person");
auto* person_schema = kj::_::readMaybe(person_maybe);
// how can I read "person.type.example" out of the Person struct?
Any guidance on the matter is appreciated, thanks!
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