__doc__ for functions, classes, objects etc.

Allen Wirfs-Brock allen at wirfs-brock.com
Wed Aug 31 07:38:24 PDT 2011

On Aug 31, 2011, at 1:57 AM, Dmitry A. Soshnikov wrote:

> On 30.08.2011 20:39, Allen Wirfs-Brock wrote:
>> On Aug 30, 2011, at 12:39 AM, Dmitry A. Soshnikov wrote:
>>> OK, let's up the topic. Seems there are no technical issues in the proposed thing -- we can simply either accept it or not. The question is whether it's needed and sound proposal and the feature to have in ECMAScript.
>> There certainly are technical issues.
>> To start, by making this part of the core language you would be defining a feature that can be used by any application code.  For example, a program might choose to encode essential runtime metadata as its "documentation".  Because of that possibility, the [[Documentation]] information must always be available at runtime.  Minimizers or obfuscators could not remote documentation comments because of the possibility of breaking such programs.
> Sure, though I don't think that application level code have to be dependent in logic on documentation string. The doc-string is just the _addition for debug_. No more, no less. It's when you use a new lib (my example with Redis's `get` method which should accept callback), you just get this help directly "from here" without going to some websites (which can even be down for this time) and solve the problems much faster. And for minified scripts, I think the option "Remove doc-comments" is the case.

When designing language features, a designer always has some specific use cases in mind.  But that doesn't restrict users of the language from discovering other use cases. Once a feature is  incorporated into a language, implementation have to support all possible use cases, not just the original intended use case.   That's why it is important for language designer to think broadly about all conceivable uses and feature interaction when extending a language. Sure, no application is required to have logic dependencies upon the content of a documentation string but once they exist any application could have such dependencies. As a language designers you have to think about the implications of such usages.  It isn't good enough to just say that wasn't the intended use of the feature.


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