Documenting fake classes - c++

I have a function which exposes all of my required C++ functions to Lua, there are various tables representing different aspects of my "Scripting API", what I wish to do is use doxygen to make a scripting reference using the C++ code that exposes these script functions.
I have tried to make 'fake' classes in the body of the function, which successfully makes a new entry with the name I have given it, for instance if I make a table named 'Math' which has several functions exposed on it, how would I also make 'fake' member functions in this 'fake' class, I have tried to simply pass in \fn defining the function, however it does not show up as they are not actually real members to add a description to. How would I create this sort of effect in doxygen without hand righting a verbatim definition of every class, but instead treat the comment block as if it were a real class with real members?

It sounds like you're trying to document Lua code as if they were C++. Maybe it's possible, but it's probably more trouble than it's worth.
If you're trying to document Lua code with doxygen, maybe you could try doxygen-lua.
If your Lua API is small, you could just write a page by hand, with \ref's to the relavent C++ code. (Kind of hacky, but I've done this before.)
You could also consider using some other doc generator for your Lua API, such as LuaDoc, or anything else listed on the lua-users wiki DocumentingLuaCode.

I ended up writing a fake .doxy file which had typenames similar to lua values, apparently doxygen will document any type to throw at it.

Related

Creating a new c++ object from within a lua script?

---Context---
I want to have a class called "fileProcessor". This class is completely static and merely serves as a convinient namespace (within my normal library namespace) for some global function. This is a basic blueprint of the class with only the relevant stuff
class fileProcessor{
private:
lua_State* LUA_state;
public:
static std::variant<type1,type2> processFile(const char* filePath,const char* processorScript);
}
Please note again that I ommitted most of the stuff from the class so if anything seems odd ignore it.
What process file is supposed to do is:
Read the filePath file, storing all directives including it (this is my own filetype or style of syntax. This is already handeled correctly). The directives are stored with strings, one for the command and one for everything after it.
Read the script file and check if it has a commented out fileProcessor line at the top. This is to make sure that the lua script loaded is relevant and not some random behaviour script
Load and compile the lua script.
Make all read directives available (they are saved in a struct of 2 strings as mentioned before)
Run the file and recieve a object back. The object should only be of types that I listed in the return type (variant)
I am having problems with step 4 and one vital part of the scripting.
---Question---
How can I make the creation of a full new object of type1 or type2 possible within lua, write to it from within lua and then get it back from the lua stack into c++ and still know if its type1 or type2?
---No example provided since this question is more general and the only reason I provided my class is for context.---
It seems like you are trying to do it the other way around. I quote a part of this answer:
...you are expecting Lua to be the primary language, and C++ to be the client. The problem is, that the Lua C interface is not designed to work like that, Lua is meant to be the client, and all the hard work is meant to be written in C so that Lua can call it effortlessly.
If you are convinced there is no other way that doing it other way around you can follow the workaround that answer has given. Otherwise I think you can achieve what you need by using LUA as it meant to be.
LUA has 8 basic types (nil, boolean, number, string, userdata, function, thread, and table). But you can add new types as you require by creating a class as the new type in native C++ and registering it with LUA.
You can register by either:
Using some LUA helper for C++ like luna.h (as shown in this tutorial).
Pushing a new lua table with the C++ class (check this answer).
Class object instance is created in your native C++ code and passed to LUA. LUA then makes use of the methods given by the class interface.

Cross-compiling plugins for multiple DCCs

Been using Haxe off and on for a few years, and I feel like this is something the compiler might be abusable for:
Is is possible to add target such that when a Haxe class is compiled, it can introspect the compiled code and generate boilerplate in C++? An example:
In Autodesk Maya to create a plugin node, you have to have a number of special functions overridden in a child class. Attributes on the node have to be declared first in the header, then declared statically in the cpp file, and finally added in a particular way (with error checks) in one of the function overrides. Apart from that, you have to write functions that register and de-register the plugin from the system. The pattern is just non-trivial enough that simple search / replace isn't good enough; you have to replace text in different patterns in different places, and also add function calls depending on the type of attributes and the attribute's settings.
A node with the same behavior in Foundry's Modo is very different-- you have to define three classes and compose functionality.
In both cases, the way you access data from within the node is also different, so if you were to wrap a single C++ function for both programs you'd be doing a lot of work outside the function just to prep the data in an agnostic way.
I'd like to be able to write a single node using Haxe code and generate C++ code from the Haxe class. In the case of Maya, it would subclass from MPxNode and provide the proper function overrides. In the case of Modo, it would generate the required classes properly. And in the future if I wanted to target Cinema 4D, I would add an additional target and compile against that SDK to create its version of the same functionality (probably a Tag).
I've actually done this partly in Python (generating C++ code with stubs for node functionality) and while it works, I've always been curious if there could be a better way to do this through Haxe directly. But again, it's something where the compiler would have to be aware of the structure of the Haxe class and the data within it in order to generate the proper code for each target.
Thanks in advance!

Is there a way to create a constrained data type in Clojure?

As an example, a string that contains only a valid email address, as defined by some regex.
If a field of this type would be a part of a more complex data structure, or would be used as a function parameter, or used in any other context, the client code would be able to assume the field is a string containing a valid email address. Thus, no checks like "valid?" should be ever necessary, so approach of domaintypes would not work.
In Haskell this could be accomplished by a smart constructor (section 1.2) and in Java by ensuring the type is immutable (all setters private) and by adding a check in the constructor that throws a RuntimeException if the string used to create the type doesn't contain a valid email address.
If this is impossible in plain Clojure, I would like to see an example implementation in some well known extensions of the language, like Typed Clojure.
Ok, maybe, I understand now a question and I formulate in the comment my thoughts not really well. So I try to suggest an admissible solution to your question and then I try to explain some ideas I tried to tell in the comment.
1) There is a gen-class that generates compiled bytecode for a class and you can set constructor for the class there.
2) You can create a record with defrecord in some namespace that is private by convention in your project, then you
create another namespace with public api and define your factory function here. So the user of your public namespace will be able to call only public functions of your public namespace. (Of course, he can call also private ones, but with some another code)
3) You can just define a function like make-email that will return a map.
So you didn't specify your data structure anywhere.
4) You can just document your code where you will warn people to use the factory function for construction.
But! In Java if your code requires some interface, then it's user problem to give to your code the valid interface implementation. So if you write even a little bit general code in Java you already has lost the property of the valid email string. This stuff with interfaces is because Java is statically typed language.
Clojure is, in general, dynamically typed, so the user, in general, should be able to pass arbitrary data structure to arbitrary function without any type problems in compile time and it's his fault if he pass the wrong data. That makes, for example, this thing possible: You create a record and create a factory (constructor) function. And you expect a record to be passed in your code. But the user can pass a map with the same keys as your record fields names and the code will work.
So, in general, if you want the user of your code to be responsible for passing a required typed in dynamically typed language, then it cost nothing for user to be responsible for constructing it in a correct way that you provide to him.
Another solutions are: User just write tests. You can specify in your api functions :pre and :post conditions to check the structure. You can use typed clojure with the ideas I wrote above. And you can use some additional declarative libraries, like that was mentioned in the first comment of #Thumbnail.
P.S. I'm not a clojure professional, so I could easily miss some better solutions.

Equivalent of "description" for a C++ class in Objective-C++?

I want to be able to debug objective-c++ code which contains instances of a c++ class quickly.
With objective-c classes, I can simply implement description to return a human readable string, and then when I po var in lldb I immediately know anything I need to know about the instance.
Is there any way I can achieve this for c++ classes used from objective-c++ code as well?
The easiest way to do this in lldb is to add a "summary formatter" for the C++ class. This web page gives a pretty good intro to how to do this:
http://lldb.llvm.org/varformats.html
Look for the section on "Type Summaries".
If the class's ivar values directly contain all you want to see about the class, then you can cons up a summary string that will present the ivar values and any markup text you think desirable without having to use the LLDB Python API's to take apart the class. If you need to do more work to produce your summary, you will have to use the Python API's as trojanfoe suggests.
For instance, if you wrote a "description" method for your C++ class, you could use LLDB's Python API's to call that method and return the string as the summary. But if possible, it is preferable to produce the summary from static knowledge of the class, since running code in the debugger is generally slower than inspecting memory.
There is also information on how to use the LLDB Python interface to produce summaries on the same page.
The Type Summaries you write can be added in your .lldbinit file, and the summary values will show up when you print an instance of the class in lldb, and also in the summary column in the Locals view in Xcode.
Note, you can do this for any type, C, C++ or ObjC. Many of the C++ STL classes and the more common Foundation classes have built-in summaries that use the same mechanism. That, and not the description method, is how lldb produces the one-line summaries you see in Xcode.

Famo.us: different ways of creating and calling functions

Hoping someone can provide an explain-like-I’m-five elucidation of the difference between the following types of functions within Famo.us, and when it’s appropriate to use them:
sampleFunction() {}
_sampleFunction() {}
SampleView.prototype.sampleFunction() {}
.bind and .call are also thrown around a lot…I understand them vaguely but not as concretely as I’d like. That might be a different question, but please feel free to use them in your explanation!
Apologies for the vagueness...wish there was more regarding this in famo.us university.
None of what you're looking at is syntax specific to Famo.us. It's actually common, if intermediate level, VanillaJS.
The _ is simply a coding convention to denote that a specific function should belong to the parent scope (ie a member/private function, whatever you prefer to call it). Javascript doesn't really have support for encapsulation - the act of blocking other classes and objects from accessing another class's functions and variables. While it is possible, it's quite cumbersome and hacky.
You'll see that Famo.us uses the underscore convention to denote that a function is a member of the class using it. Some of these functions are actually just aliases to the actual Javascript native function, for example ._add actually just call's Javascript's .add method. Of course, ._add could be updated in the future on Famo.us's end to do more in the future if that's required. You really wouldn't want to try and write over the native Javascript add. That's super bad.
The other upshot is that you can document that class and say that you can and should use the _add method for a specific purpose/scenario. You'll see that in the API docs.
Understanding prototype is a core part of what it means to be a Javascript Programmer, after all, it is a prototype driven language. MDN has a much better explanation than anything I can offer here but it's basically at the core of your classes.
If you want to extend off of an existing class (say, create your own View or Surface type) you would extend it's prototype. Check out Famous Starter Kit's App examples and see how many of them create an "AppView" class, which takes the prototype of the core View, copies it for itself, and then adds it's own functions, thus extending View without ruining the original copy.