OCaml + Cordova = more secured, typed and hybrid mobile applications.

Since several months, I began to be interested in mobile development. I found a job in Brussels in July 2015 where I learned how to develop hybrid mobile applications (one code = available for multiple mobile platforms) with Cordova and web technologies. I found it very interesting and after several month I continue to develop applications with this technology. I discovered a very great community about mobile development and some awesome frameworks like Ionic.

The majority of these frameworks use JavaScript as programming language but I don’t really like this language because you have no types, some weird things (equality between string and integer), parameters are sent as undefined if not passed, etc. I don’t really like to develop applications with JavaScript because it’s very ugly (even if I think it’s OK for prototyping, but not in production).

I discovered OCaml at the university, a very powerful programming language with inferred static type, type checking at compilation time, an extraordinary community and… a compiler from OCaml to JavaScript! So, I wanted to use this language to develop mobile applications with Cordova: it will be my university project for a semester.

The goal of my project is to be able to use native components of smartphones such like accelerometer, camera, send sms, etc in OCaml.

What are Cordova, js_of_ocaml and gen_js_api?

  • Cordova allows you to develop hybrid mobile applications using web technologies such as HTML, CSS and JavaScript. For more information, see the official website. Through Cordova plugins, you can access to the native components. To learn how to make Cordova plugins, see the official tutorial. You can find the official Cordova plugin list here.
  • js_of_ocaml provides a compiler from OCaml to JavaScript. Since Cordova applications use JavaScript, js_of_ocaml provides a way to develop mobile application using OCaml. For more info, see the Ocsigen project which contains js_of_ocaml.
  • gen_js_api aims at simplifying the creation of OCaml bindings for JavaScript libraries. It must currently be used with the js_of_ocaml compiler, although other ways to run OCaml code “against” JavaScript might be supported later with the same binding definitions (for instance, Bucklescript, or direct embedding of a JS engine in a native OCaml application).

All bindings are developed with gen_js_api and aims to be functional, typed and very close to the JavaScript interface.

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GSMath

GSMath: a math hybrid library.

In the same idea than GSLib GSMath is a library, available in multiple languages, keeping the same structure and the same functions. GSMath provides functions to do linear algebra (matrix), differential analysis, basic algebra, trigonometry,…

What’s an hybrid library and why ?

I think programming languages must be seen as a tool, not as a “raw material”.

I don’t say every programming languages is equivalent in the sense there’re no needs to compare them. There’re better programming languages than other, and it depends on what you have to do. There’re also different theoric aspects of programming languages which matters a lot. For example, you’ve to be foolish to code a JQuery like or a web render in brainf***. As a tool, there’re better tools than other (but it’s not the subject of this article, maybe later).

I think a programming language must be seen as a way to communicate with your computer as you want: the compiler or interpreter is there to translate to your machine. So, why do we have to learn a new standard library when we learn a new programming language ? Why do we have to talk differently to each interpreters and compilators ?
It’s not very productive and we don’t often remember basic functions because we have to switch between different syntaxes.

You shouldn’t be afraid about the syntax and the semantic to learn a new programming language or when you work with several languages.

For these reasons, I began to write a library I called GSMath. I say it’s an hybrid library because you can use it in the programming language you want with the same namespace and the same algorithms for the implementation. The last point is I think important because when we want to learn a new programming language, it’s a good way to learn to study how standards libraries are implemented.

GSMath isn’t always the fastest and the more efficient implementations of math libraries.

GSLib

GSLib: an hybrid library.

When we learn a new programming language, we must read a lot of documentation to know which basic functions do what we want such as create a linked list, a tree, a graph, …
GSLib is a library, written in multiple languages, keeping the same structure and providing the same functions and data structures for all languages, which let you easily switch to a new language.

What’s an hybrid library and why ?

I think programming languages must be seen as a tool, not as a “raw material”.

I don’t say every programming languages is equivalent in the sense there’re no needs to compare them. There’re better programming languages than other, and it depends on what you have to do. There’re also different theoric aspects of programming languages which matters a lot. For example, you’ve to be foolish to code a JQuery like or a web render in brainf***. As a tool, there’re better tools than other (but it’s not the subject of this article, maybe later).

I think a programming language must be seen as a way to communicate with your computer as you want: the compiler or interpreter is there to translate to your machine. So, why do we have to learn a new standard library when we learn a new programming language ? Why do we have to talk differently to each interpreters and compilators ?
It’s not very productive and we don’t often remember basic functions because we have to switch between different syntaxes.

You shouldn’t be afraid about the syntax and the semantic to learn a new programming language or when you work with several languages.

For these reasons, I began to write a library I called GSLib. I say it’s an hybrid library because you can use it in the programming language you want with the same namespace and the same algorithms for the implementation. The last point is I think important because when we want to learn a new programming language, it’s a good way to learn to study how standards libraries are implemented.

GSLib isn’t always the fastest and the more efficient implementations of stardard libraries. For example, if you’re on an embedded system, use GLib is a better library because asm code is used to optimize on the platform.
Due to a bad manipulation, GSLib must be rewritten. A documentation and implementation in pseudo-code will be soon available.