RFC: 204 - Go language bindings #206
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| would need to generate an interface in addition to a concrete struct for each JSII class. | ||
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| The JSII [ClassType](https://github.com/aws/jsii/blob/master/packages/%40jsii/spec/lib/assembly.ts#L803) provides information on whether a | ||
| class is abstract, whether it extends another class, and whether it implements other interfaces. We will discuss each case in turn. |
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I'd like to see an example involving model protected members, and also polymorphic calls. Combining them into one example, how about:
class Animal {
public speak() {
console.log(this.voice());
}
protected voice() {
return '...';
}
}
class Poodle extends Animal {
protected voice() {
return 'arf';
}
}
// Expecting to see 'arf'
new Poodle().speak();There was a problem hiding this comment.
Does the example below showing how move() is overridden not fit the bill?
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Go may need to require "protected" members to be exported as public
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I think in jsii visibility is already required to be unchanged between inheriting classes (and hopefully releases, TO BE CHECKED), so we could do something like prepend a _ for protected members.
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Does the example below showing how
move()is overridden not fit the bill?
I don't think so. What I'm looking for is a polymorphic self call.
In all other forms of delegation you've shown, a child class is upcalling to its superclass--but that is fine, it knows the type of that superclass.
What if a superclass calls into a virtual method on itself, that may be implemented and overridden by a subclass? You'd need a reference to the current object's interface type, not its struct type.
I mean, I guess there's probably syntax for it, I just don't know what it is.
Previously, the CDK to generate the cloudformation templates lived elsewhere. Now they are inlined. In future, the aim is that Go itself can be used for these: aws/aws-cdk-rfcs#206 That's the hope, anyway!
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| ### Case 4: Abstract Classes | ||
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| These should be able to be handled much in the same way as regular classes, by generating an interface and a struct. The struct generation is still |
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Is there a way to prevent direct instantiation of these structs to mimic the "abstract" part? Maybe a default New that throws an error?
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Hm, perhaps but that wouldn't necessarily stop anyone from trying to declare the generated struct literal, right?
text/204-golang-bindings.md
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| export interface HealthCheck { | ||
| readonly command: string[]; | ||
| readonly interval?: cdk.Duration; | ||
| readonly retries?: number; | ||
| readonly startPeriod?: cdk.Duration; | ||
| readonly timeout?: cdk.Duration; | ||
| } | ||
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| function renderHealthCheck(hc: HealthCheck): cfntaskdefinition.HealthCheckProperty { | ||
| return { | ||
| command: getHealthCheckCommand(hc), | ||
| interval: hc.interval != null ? hc.interval.toSeconds() : 30, | ||
| retries: hc.retries !== undefined ? hc.retries : 3, | ||
| startPeriod: hc.startPeriod && hc.startPeriod.toSeconds(), | ||
| timeout: hc.timeout !== undefined ? hc.timeout.toSeconds() : 5, | ||
| }; | ||
| } | ||
| ``` | ||
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| Go translation (Run example in the [Go playground](https://play.golang.org/p/o84uoUGORYH): | ||
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| ```go | ||
| package ecs | ||
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| type IHealthCheck interface{ | ||
| GetCommand() []string | ||
| GetInterval() cdk.Duration; | ||
| GetRetries() int | ||
| GetStartPeriod() cdk.Duration; | ||
| GetTimeout() cdk.Duration; | ||
| } |
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This example is missing using pointer for the TS optional members. It may also be helpful to callout how optional properties, (and I assume function parameters) are translated into Go.
| would need to generate an interface in addition to a concrete struct for each JSII class. | ||
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| The JSII [ClassType](https://github.com/aws/jsii/blob/master/packages/%40jsii/spec/lib/assembly.ts#L803) provides information on whether a | ||
| class is abstract, whether it extends another class, and whether it implements other interfaces. We will discuss each case in turn. |
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Go may need to require "protected" members to be exported as public
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@Mergifyio update |
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