User Extensions
The extension package system allows the language compiled by Bigloo to be
extended and this is achieved by associating an
extension file with a
suffix. The
extension file is loaded at the beginning of a compilation
and it can do three things: call extern programs (unix programs); define
macros; modify the values of some of the compiler's variables (for example,
the list of the libraries to be linked with). The Bigloo's initializing
procedure is the following:
- If it exists, Bigloo loads the runtime-command file, see
Section Compiler Description.
- It then parses the command line to find the source file to compile.
- It extracts the source file suffix and looks it up in its
*auto-mode* variable.
- If the suffix is found, the associated file is loaded. This
file could contain a function named *extend-entry*
which must accept a list as argument. It is
invoked with the Bigloo's unparsed arguments.
- The result of the
*extend-entry* application has to be a regular list of arguments and these are parsed by Bigloo.
For now, two extension packages exist: the Meroon package which
is a native version of the Christian Queinnec object
language; the Camloo [SerranoWeis94] package which is a front
end compiler for the Caml language [Caml-light]
Furthermore, Bigloo supports the
-extend option which forces
the usage of an extension file. When Bigloo encounters this option, it
immediately loads the extension file, invoking the function
*extend-entry* with the list of arguments which have not
been parsed yet.
The extension files are always sought in the directory containing the
Bigloo's libraries.
User pass
Bigloo allows the user to add a special pass to the regular compilation,
this pass taking place
before macro expansion. There are
two ways to add a user pass.
- Add a compiled pass: The module
user_user (in the ``comptime/User/user.scm'' file) is the user entry pass point.
To add a compiled pass, put the code of the pass in this directory, import
your new modules in user_user and modify the user-walk function.
- Add an interpreted pass: Set the value of
*user-pass*, which has to be a unary function, in your .bigloorc file and
Bigloo will invoke it with the code as argument.