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Other development tools

We have restricted ourselves up to now to the Objective CAML distribution. Nevertheless the community of developers using this language is active, as demonstrated by the number of messages on the mailing list. Numerous tools, libraries, and extensions are used to facilitate development. In the following we detail the use of tools for editing, syntax extension, interfacing with other languages and parallel programming. We mention as well the numerous graphical interface libraries. Most of these contributions can be found on the ``Caml Hump'' site:


Editing tools

There are several modes recognizing Objective CAML syntax for the emacs editor. These modes are used to automatically indent text in the course of entering it, making it more readable. This is an alternative to the interaction window under Windows. Since emacs runs under Windows, the Objective CAML toplevel can be launched within one of its windows.

Syntax extension

The lexical and syntactic analysis tools provided by the distribution are already quite complete, but they don't support extending the syntax of the language itself. The camlp4 tool (see the link on page ??) is used in place and instead of Objective CAML's syntactic analyzer. The latter's compilers have only to proceed to typing and code generation. This tool allows the user to extend the syntax of the language, or to change to the original syntax. Moreover it offers pretty-printing facilities for the generated syntax trees. In this way it becomes easy to write a new toplevel for any Objective CAML syntax extension, or even another language implemented in Objective CAML.

Interoperability with other languages

Chapter 12 detailed how to interface the Objective CAML language with C. A multi-language application takes advantage of the features of each one, all while making different codes sharing a single memory space live in harmony. Nevertheless encapsulating C functions to make them callable from Objective CAML requires some tedious work. To simplify it, the camlIDL tool (see the link on page ??) supplies an interface generator and tools for importing COM (Windows) components into Objective CAML. The interfaces are generated from an IDL interface description file.

Graphical interfaces

The Graphics library allows the development of drawings and simple interactions, but it can't be considered a graphical interface worthy of the name. Chapter 13 has shown how this library could be extended to construct graphical components responding to some interactions. Using Graphics as a base allows us to preserve the portability of the interface between different platforms (X-Windows, Windows, MacOS), but limits its use to the low level of events and graphics contexts.

Several projects attempt to fill this gap, unfortunately none succeeds in being complete, portable, documented, and simple to use. Here is a list (extracted from the ``Caml Hump'') of the main projects: Despite the efforts of the community, there is a real lack of tools for constructing portable interfaces. It may be hoped that LabTk becomes portable to different systems.

Parallel programming and distribution

Threads and sockets already offer basic mechanisms for concurrent and distributed programming. Interfacing with the C language allows the use of classic parallel programming libraries. The only thing missing is an interface with CORBA for invoking methods of remote objects. On the other hand, there are numerous libraries and language extensions which use different models of parallelism.


The two main parallel programming libraries, MPI (Message Passing Interface) and PVM (Parallel Virtual Machine), are interfaced with Objective CAML. Documentation, links, and sources for these libraries can be found on the site

The ``Caml Hump'' contains the various HTTP addresses from which the versions interfaced with Objective CAML can be downloaded.


Numerous parallel extensions of Caml-Light or Objective CAML have been developed:
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