Source code annotations alla Java

Jacob Carlborg doob at
Thu Jan 20 10:17:22 PST 2011

On 2011-01-20 14:47, Justin Johansson 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?

Depending on what you want to do you can create a template mixin that 
accepts string(s)/alias(es). For example: for the serialization library 
( I'm working on the following syntax 
is used:

class Foo
     int x;
     int y;
     int z;

     mixin NonSerialized!(z);

The above mixin indicates that the "z" instance variable shouldn't be 
serialized. This is (currently) achieved by defining a field in the 
mixed in template (which will be added to the class) which is a struct 
containing the string of the filed which shouldn't be serialized. Then I 
iterate over all the fields in the class with .tupleof and collects all 
mixed in fields in a list. Then I know what fields to skip later during 
the serialization.

/Jacob Carlborg

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