Source code annotations alla Java

Jacob Carlborg doob at
Thu Jan 20 12:03:55 PST 2011

On 2011-01-20 19:18, Steven Schveighoffer wrote:
> On Thu, 20 Jan 2011 13:07:58 -0500, Jacob Carlborg <doob at> wrote:
>> On 2011-01-20 15:02, Steven Schveighoffer wrote:
>>> On Thu, 20 Jan 2011 08:47:28 -0500, Justin Johansson <jj at>
>>> wrote:
>>>> Not long ago the Java Language people introduced the idea of
>>>> annotations together with an annotation processing tool (apt).
>>>> Now perhaps the idea of source code annotations is not actually a Java
>>>> invention per se, however for someone learning D is there any
>>>> equivalent idiom [of Java annotations] in the D language?
>>> Haven't used Java since they added annotations, but I think they are
>>> like C# attributes?
>>> In any case, D has an annotation syntax like:
>>> @property
>>> But I think at the moment, annotations have no custom ability. Only
>>> compiler-defined annotations are allowed. This may change in the future,
>>> but probably not short-term. FWIW, I think we need a much richer
>>> runtime-reflection capability before we can use custom annotations to
>>> any great effect.
>>> -Steve
>> I would rather formulate it like: currently D has a syntax for
>> keywords that are similar to Java annotations.
> I don't think it's the same thing. Keywords are not allowed to be used
> anywhere else, even for things that would parse properly were they not
> keywords. They are anchors for the parser to determine where it is. In
> contrast, a compiler-defined annotation is parsed just the same as a
> custom one, it's just that the meaning is predefined.
> For example, you can legally do:
> int property;
> without error, but this won't even get past the parsing stage:
> int struct;
> -Steve

I assume you meant "int @property;"?

/Jacob Carlborg

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