Clojure's Fleet Templates: how to use "fleet-ns"? - templates

I'm working on a web app using Clojure, Ring, Composure, and Fleet. I like the flexibility of Fleet and I find the syntax of its template files easy to read and intuitive. However, the documentation is sparse and I'm having difficulty understanding the use of macro, "fleet-ns" which produces namespaced functions for .fleet files in a directory tree.
In particular, the README.md file makes this statement about the production of these functions:
— Several functions will be created for each file. E.g. file posts.html.fleet will
produce 3 functions: posts, posts-html and posts-html-fleet.
I can't find any explanation of why there are three functions, what they each is used for, or what their differences are.
The examples I've found by search have been fragmentary, incomplete or obscured by other issues.
Overall my feeling is that the adoption of this excellently conceived package is being hampered by the lack of documentation. I am inclined to improve if I can figure out a bit more about the way Fleet works.
Any help, pointers, or canonical examples appreciated.

Indeed documentation is scarce. Maybe you can use enlive instead. There are plenty of examples available on the web.
You can also read (if you haven't already) the following:
http://cleancode.se/2011/01/04/getting-started-with-moustache-and-enlive.html
and a very nice paper by Glenn Vanderburg:
http://steve.vinoski.net/pdf/IC-Clojure_Templating_Libraries_Fleet_and_Enlive.pdf

Related

GCC ext headers — up-to-date documentation?

I'm quite confused by this paradox:
GCC ext apparently contains lots of broadly useful functionality. For example, ext/pb_ds/assoc_container.h lets you build an order statistic tree just by specifying particular template arguments, and ext/numeric contains the power(..) algorithm for O(lg N) exponentiation of a generic object to a non-zero integer power — this algorithm gets written from scratch all the time. There is also the rope data structure, algorithms for random sampling, and many others. Not things you would use every day, but definitely things that would be handy every other year or so.
Almost nobody seems to be using them. There is very little discussion on the web. There are some bug reports, and posts like this one suggesting either that these things are buggy and unmaintained or that there is no definitive guide on how to use them properly.
Now, trying to find the documentation, I type in gcc "ext" into Google, and get https://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/ as the first result. Going to Examples of Associate Containers gets me to another table of contents, but clicking on e.g. the link to basic_set.cc gives me a 404 page.
At this point I'm not even sure if this code had received enough testing to be able to rely on it for serious applications.
Is there any proper documentation for when and how to use #include <ext/numeric> and the like? Or at least examples and asymptotic complexity estimates?
Since it sounds like you've found a defect in the documentation, I'd suggest sending an e-mail to libstdc++#gcc.gnu.org to subscribe to the mailing list. I was able to find a mirror for the libstdc++ test suite on Github, which contains the examples you want. If you're looking for documentation for ext_numerics, it's at gcc.gnu.org/onlinedocs/libstdc++/manual/ext_numerics.html.

How should I document a Lua API/object model written in C++ code?

I am working on documenting a new and expanded Lua API for the game Bitfighter (http://bitfighter.org). Our Lua object model is a subset of the C++ object model, and the methods exposed to Lua that I need to document are a subset of the methods available in C++. I want to document only the items relevant to Lua, and ignore the rest.
For example, the object BfObject is the root of all the Lua objects, but is itself in the middle of the C++ object tree. BfObject has about 40 C++ methods, of which about 10 are relevant to Lua scripters. I wish to have our documentation show BfObject as the root object, and show only those 10 relevant methods. We would also need to show its children objects in a way that made the inheritance of methods clear.
For the moment we can assume that all the code is written in C++.
One idea would be to somehow mark the objects we want to document in a way that a system such as doxygen would know what to look at and ignore the rest. Another would be to preprocess the C++ code in such a way as to delete all the non-relevant bits, and document what remains with something like doxygen. (I actually got pretty far with this approach using luadoc, but could not find a way to make luadoc show object hierarchy.)
One thing that might prove helpful is that every Lua object class is registered in a consistent manner, along with its parent class.
There are a growing number of games out there that use Lua for scripting, and many of them have decent documentation. Does anyone have a good suggestion on how to produce it?
PS To clarify, I'm happy to use any tool that will do the job -- doxygen and luadoc are just examples that I am somewhat familiar with.
I have found a solution, which, while not ideal, works pretty well. I cobbled together a Perl script which rips through all the Bitfighter source code and produces a second set of "fake" source that contains only the elements I want. I can then run this secondary source through Doxygen and get a result that is 95% of what I'm looking for.
I'm declaring victory.
One advantage of this approach is that I can document the code in a "natural" way, and don't need to worry about marking what's in and what's out. The script is smart enough to figure it out from the code structure.
If anyone is interested, the Perl script is available in the Bitfighter source archive at https://code.google.com/p/bitfighter/source/browse/luadoc.pl. It is only about 80% complete, and is missing a few very important items (such as properly displaying function args), but the structure is there, and I am satisfied the process will work. The script will improve with time.
The (very preliminary) results of the process can be seen at http://bitfighter.org/luadocs/index.html. The templates have hardly been modified, so it has a very "stock" look, but it shows that things more-or-less work.
Since some commenters have suggested that it is impossible to generate good documentation with Doxygen, I should note that almost none of our inline docs have been added yet. To get a sense of what they will look like, see the Teleporter class. It's not super good, but I think it does refute the notion that Doxygen always produces useless docs.
My major regret at this point is that my solution is really a one-off and does not address what I think is a growing need in the community. Perhaps at some point we'll standardize on a way of merging C++ and Lua and the task of creating a generalized documentation tool will be more manageable.
PS You can see what the markup in the original source files looks like... see https://code.google.com/p/bitfighter/source/browse/zap/teleporter.cpp, and search for #luaclass
Exclude either by namespace (could be class as well) of your C++ code, but not the lua code
EXCLUDE_SYMBOLS = myhier_cpp::*
in the doxygen config file or cherry pick what to exclude by using
/// #cond
class aaa {
...
...
}
/// #endcond
in your c++ code.
I personally think that separating by namespace is better since it reflects the separation in code + documentation, which leads to a namespace based scheme for separation of pure c++ from lua bindings.
Separating via exclusion is probably the most targeted approach but that would involve an extra tool to parse the code, mark up relevant lua parts and add the exclusion to the code. (Additionally you could also render special info like graphs separately with this markup and add them via an Image to your documentation, at least that's easy to do with Doxygen.). Since there has to be some kind of indication of lua code, the markup is probably not too difficult to derive.
Another solution is to use LDoc. It also allows you to write C++ comments, which will be parsed by LDoc and included into the documentation.
An advantage is that you can just the same tool to document your lua code as well. A drawback is that the project seems to be unmaintained. It may also not be possible to document complex object hierarchies, like the questioner mentioned.
I forked it myself for some small adjustments regarding c++. Have a look here.

What is a good place to host a community-driven examples site?

I'm a contributer to the Raphael project, and one thing we need is a central place for documentation and, IMHO, a good place for people to add examples of how to use the library to accomplish various tasks.
One of the contributers has done a great job of managing all this information himself so far, on his own personal site, but of course that means lots of maintenance for him, and makes it more difficult to make improvements, add new examples, and so on.
Is there a hosted wiki of some sort that supports allowing examples to be added? Ideally, it would allow the examples to be run; I know that there are some security questions about allowing contributed JavaScript to run, so I'd be fine with having an approval process if that's necessary, or worst case, at least an easy way to write example code and have it nicely syntax highlighted.
Anyone have a suggestion? Also, if this would be better posted to a different exchange, let me know; it's semi-programming related, but I thought it fit better here than on superuser.com.
There are places like sourceforge, Google's Code repository, and as mentioned in the comments, github.

Dual purpose code commenting(users & maintainers)...HOW? [closed]

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I am writing a C++ static library and I have been commenting with doxygen comments in the implementation files. I have never really had to care very much about documentation but I am working on something now that needs to be documented well for the users and also I am trying to replace my previous bad habit of just wanting to code and not document with better software engineering practices.
Anyway, I realized the other day that I need a couple different types of documentation, one type for users of the library(doxygen manual) and then comments for myself or a future maintainer that deal more with implementation details.
One of my solutions is to put the doxygen comments for file, class, and methods at the bottom of the implementation file. There they would be out of the way and I could include normal comments in/around the method definitions to benefit a programmer. I know it's more work but it seems like the best way for me to achieve the two separate types of commenting/documentation. Do you agree or have any solutions/principles that might be helpful. I looked around the site but couldn't really find any threads that dealt with this.
Also, I don't really want to litter the interface file with comments because I feel like it's better to let the interface speak for itself. I would rather the manual be the place a user can look if they need a deeper understanding of the library interface. Am I on the right track here?
Any thoughts or comments are much appreciated.
edit:
Thanks everyone for your comments. I have learned alot from hearing them. I think I have a better uderstanding of how to go about separating my user manual from the code comments that will be useful to a maintainer. I like the idea that #jalf has about having a "prose" style manual that helps explain how to use the library. I really think this is better than just a reference manual. That being said...I also feel like the reference manual might really come in handy. I think I will combine his advice with the thoughts of others and try to create a hybrid.(A prose manual(using the doxygen tags like page, section, subsection) that links to the reference manual.) Another suggestion I liked from #jalf was the idea of the code not having a whole manual interleaved into it. I can avoid this by placing all of my doxygen comments at the bottom of the implementation file. That leaves the headers clean and the implementation clean to place comments useful for someone maintaining the implementation. We will see if this works out in reality. These are just my thoughts on what I have learned so far. I am not positive my approach is going to work well or even be practical. Only time will tell.
I generally believe that comments for users should not be inline in the code, as doxygen comments or anything like that. It should be a separate document, in prose form. As a user of the library, I don't need to, or want to, know what each parameter for a function means. Hopefully, that's obvious. I need to know what the function does. And I need to know why it does it and when to call it. And I need to know what pre- and postconditions apply. What assumptions does the function make when I call it, and what guarantees does it provide when it returns?
Library users don't need comments, they need documentation. Describe how the library is structured and how it works and how to use it, and do so outside the code, in an actual text document.
Of course, the code may still contain comments directed at maintainers, explaining why the implementation looks the way it does, or how it works if it's not obvious. But the documentation that the library user needs should not be in the code.
I think the best approach is to use Doxygen for header files to describe (to the users) how to use each class/method and to use comments within the .cpp files to describe the implementation details.
Well done, Doxygen commenting can be very useful both when reading code and when reading generated HTML. All the difficulty lies in Well done.
My approach is as following:
For users of library, I put Doxygen comments in header files for explaining what is the purpose of that function and how to use it by detailing all arguments, return values and possible side effects. I try to format it such that generated documentation is a reference manual.
For maintainers, I put basic (not Doxygen) comments in implementation files whenever self-commenting code is not enough.
Moreover, I write a special introductory file (apart from the code) in Doxygen format for explaining to new users of libray how to use the various features of the library, in the form of a user's guide which points to details of reference manual. This intro appears as the front page of the Doxygen generated documentation.
Doxygen allows the creation of two versions of the documentation (one for users and one for "internal use") through the \internal command and the INTERNAL_DOCS option. It is also possible to have a finer grained control with conditional sections (see the \if command and the ENABLED_SECTIONS option.)
As others have already noted, it is also useful to provide users (and also maintainers sometimes) something at a higher level than strictly code comments. Doxygen can also be used for that, with the \mainpage, \page, [sub[sub]]section and \par commands
I recommend you to take a look at this paper: http://www.literateprogramming.com/knuthweb.pdf
I normally applied those ideas to my projects (using Doxygen). It also helps in keeping the doc up to date because it is not necessary to leave the IDE, so one can make annotations while coding and, later on, revise the final pdf document to see what needs to be updated or more detailed.
In my experience, Doxygen requires some work so that the pdf look nice, the graphs and pics in place, etc. but once you find your ways and learn the limitations of the tool, it gets the job done quite well.
My suggestion, besides what Kyle Lutz and Eric Malefant have already said, is to put long explanations about related classes in its own file (I use a header file for that) and add references to other parts using Doxygen tags. You only need to include those headers in the Doxygen configuration file (using pattern matching). This avoids cluttering your headers too much.
There is no quick easy answer, good documentation is hard.
I personally feel a layered model is best.
high level docs in prose. Pictures and videos are very appropriate.
reference level docs should Doxygen (well done doxygen, not just off hand comments).
maintainer docs should not show up in the reference docs, but they could still be doxygen as pointed out by by Éric.
I really like the documentation style used in RakNet. The author uses extensive Doxygen comments and provides a generated reference manual. He also provides some plain html tutorials. Best of all he supplies video walk-throughs of some of the more complicated features.
Another good example is SFML. The quality isn't as good as RakNet but it's still very good. He provides a good overview page in the doxygen generated documentation. There are a few plain html tutorials and a plain html Features/Overview page.
I prefer these styles as Doxygen generated documentation is generally too low level when I'm just starting out, but perfectly concise once I'm in the groove.

C/C++ Header file documentation [closed]

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What do you think is best practice when creating public header files in C++?
Should header files contain no, brief or massive documentation? I've seen everything from almost no documentation (relying on some external documentation) to large specifications of invariants, valid parameters, return values etc. I'm not sure exactly what I prefer, large documentation is nice since you've always access to it from your editor, on the other hand a header file with very brief documentation can often show a complete interface on one or two pages of text giving a much better overview of what's possible to do with a class.
Let's say I go with something like brief or massive documentation. I want something similar to javadoc where I document return values, parameters etc. What's the best convention for that in c++? As far as I can remember doxygen does good stuff with java doc-style documentation, but are there any other conventions and tools for this I should be aware of before going for javadoc style documentation?
Usually I put documentation for the interface (parameters, return value, what the function does) in the interface file (.h), and the documentation for the implementation (how the function does) in the implementation file (.c, .cpp, .m).
I write an overview of the class just before its declaration, so the reader has immediate basic information.
The tool I use is Doxygen.
I would definetely have some documentation in the header files themselves. It greatly improves debugging to have the information next to the code, and not in separate documents. As a rule of thumb, I would document the API (return values, argument, state changes, etc) next to the code, and high-level architectural overviews in separate documents (to give a broader view of how everything is put together; it's hard to place this together with the code, since it usually references several classes at once).
Doxygen is fine from my experience.
I believe Doxygen is the most common platform for generating documentation, and as far as I know, it's more or less able to cover JavaDoc-notation (not limited to of course). I've used doxygen for C, with OK results, I do think it's more suitable for C++ though. You might want to look into robodoc as well, although I think Occam's Razor will tell you to rather go for Doxygen.
Regarding how much documentation, I've never been a documentation-fan myself, but whether I like it or not, having more documentation always beats having no documentation. I'd put the API-documentation in the header file, and the implementation documentation in the implementation (stands to reason, doesn't it?). :) That way, IDEs have the chance to pick it up and show it during autocompletion (Eclipse does this for JavaDocs, for example, perhaps also for doxygen?), which shouldn't be underestimated. JavaDoc has this additional quirk that it uses the first sentence (i.e. up to the first full stop) as a brief description, don't know if Doxygen does this though, but if so, it should be taken into consideration when writing the documentation.
Having a lot of documentation runs the risk of being out of date, however, keeping the documentation close to the code will give people a chance to keep it up to date, so you should definately keep it in the source/header files. What shouldn't be forgotten though is the production of documentation. Yes, some people will use the documentation directly (through the IDE or whatever, or just reading the header file), but some people prefer other ways, so you should probably consider putting your (regularly updated) API documentation online, all nice and browsable, as well as perhaps producing man-files if you're targeting *nix-based developers.
That's my two cents.
Put enough into the code that it can stand alone. Nearly every project I've been in where the documentation was separate, it got out of date or wasn't done, partly that if it's a separate document it becomes a separate task, partly as management didn't allow for it as a task in budgetting. Documenting inline as part of the flow works much better in my experience.
Write the documentation in a form which most editors recognise is a block; for C++ this seems to be /* rather than //. That way you can fold it and just see the declarations.
Maybe you would be interested in gtk-doc. It can be "a bit awkward to setup and use" but you can get a nice API documentation from source code, looking like this:
String Utility Functions