How to make an application a script on Linux

Question

I wrote a C ++ application that takes a complex binary file format and translates it into human readable text. By editing the text, you can recompile it back to a binary file format.

This would be more useful if the internal model of the application object was scriptable. On Windows, I would open objects using COM or .Net, but I want this to work on Linux. I could embed a scripting language, but this is fair work, and limits users to the scripting language that I choose. Ideally, I'm looking for a way to display a DOM script from my application, which:

• Wide support in scripting languages ​​(without writing language shells)
• Cross-platform (but Linux support is important)
• In process (but this is not essential)

A few more details: I was hoping for a solution that provided similar benefits for COM. Namely, after the internal objects of the application are opened via COM, they can be manipulated using any scripting language in the same way that JavaScript can work with the HTML DOM. Objects and methods are easy to detect, and many IDEs offer automatic completion of commands for your objects. Ease of use on the client side is important.

Answer 1

The usual way is to expose some CLI commands and allow users to use them in any language that writes a custom shell / script language; see fe imagemagick , which provides several commands for converting images between formats and applying transforms. This works well on any OS.

It can also work with interactive programs, although this is rare. You can use the D-BUS interface (which is becoming increasingly popular in both GNOME and KDE), although it is more suitable for handling events or sending simple commands. You might want to create an interactive or daemon program that provides a D-BUS interface (or even a simple socket / pipe), as well as some simple CLI calls that wrap send commands to make the interface much easier. See moc / mocp ("Music on the console player") or xmms2 . This works well in any OS, but it usually takes some time to develop implementation details on different OSs.

Don't be afraid to embed a full language. Languages ​​such as Lua or Guile have been designed in such a way that they are very easy to use and quite powerful. Standardization in one such language is not always bad, because it means repeatedly reusing code between users ... and the language actually matters only if you plan on users to write large pieces of code in the form of plugins.

There are several ways to open the API for several scripting languages ​​using special libraries. You can read about them fe here: Kross @Wikipedia . I have no experience with them.

I assume that your program will be closed-source ... Then the last option that I see is to open some kind of API / ABI interface that can be used by C user programs (fe compiled into a dynamic library). This way, users can create wrappers for any language they want, plus they can make code in simple C for speed. This solution can be difficult to make portable, but it gives you (and your users) the flexibility.

Please note that scripting is easy to rewrite: it is better to leave programming constructs in external languages ​​and provide only simple means of interaction with your program. I saw programs that added their own looping tools to scripting languages, although they did not add any value to the user: fe the ability to transfer multiple images at once for conversion, although this did not speed up the processing.

Answer 2

You can find the D-Bus . It provides an object oriented API with activation support.

Answer 3

I'm not quite sure what you mean by "scriptable". Do you want to have an external interface (like an API) that other programs / scripts can access? If so, then I think it's best to use sockets (Unix or TCP). They are cross-platform as they become available, and most scripting languages ​​have some way of communicating via sockets (I played with them in Python, PHP, and Java).

As a side note, if you decide to go with sockets, it would be nice to implement some kind of standardized protocol such as XML-RPC over HTTP. This will simplify the use of your API.

Again, hopefully, I realized what you mean by "scriptable". If not, just ignore my answer.