1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
[[!meta copyright="Copyright © 2008, 2009, 2010, 2011, 2012, 2013, 2014 Free
Software Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]
[[!meta title="Bindings to Other Programming Languages"]]
<!-- See also open_issues/gccgo, open_issues/gnat, open_issues/perl, and
open_issues/python. -->
The main idea of the Hurd design is giving users the ability to easily
modify/extend the system's functionality ([[extensible_system|extensibility]]).
This is done by creating [[filesystem_translators|hurd/translator]] and other
kinds of Hurd servers.
However, in practice this is not as easy as it should, because creating
translators and other servers is quite involved -- the interfaces for doing
that are not exactly simple, and available only for C programs. Being able to
easily create simple translators in RAD languages is highly desirable, to
really be able to reap the [[advantages]] of the Hurd architecture.
Originally Lisp was meant to be the second system language besides C in the GNU
system; but that doesn't mean we are bound to Lisp. Bindings for any popular
high-level language, that helps quickly creating simple programs, are highly
welcome.
Several approaches are possible when creating such bindings. One way is simply
to provide wrappers to all the available C libraries ([[hurd/libtrivfs]], [[hurd/libnetfs]]
etc.). While this is easy (it requires relatively little consideration), it may
not be the optimal solution. It is preferable to hook in at a lower level, thus
being able to create interfaces that are specially adapted to make good use of
the features available in the respective language.
These more specialized bindings could hook in at some of the lower level
library interfaces ([[hurd/libports]], [[hurd/glibc]], etc.); use the
[[microkernel/mach/MIG]]-provided [[microkernel/mach/RPC]] stubs directly; or
even create native stubs directly from the interface definitions. The
[[lisp_bindings_created_by_Flavio_Cruz|flaviocruz]] as his [[2008 GSoC
project|2008]] mostly use the latter approach, and can serve as a good example.
In his [[2011 GSoC project|2011]], Jérémie Koenig designed and began
implementing an object-oriented interface; see his [[Java status
page|user/jkoenig/java]] for details.
The task is to create easy to use Hurd bindings for a language of the student's
choice, and some example servers to prove that it works well in practice. This
project will require gaining a very good understanding of the various Hurd
interfaces. Skills in designing nice programming interfaces are a must.
Anatoly A. Kazantsev has started working on [Python
bindings](http://savannah.nongnu.org/projects/pyhurd/) last year -- if Python
is your language of choice, you probably should take his work and complete it.
There was also some previous work on [Perl
bindings](http://www.nongnu.org/hurdextras/#pith), which might serve as a
reference if you want to work on Perl.
Possible mentors: Anatoly A. Kazantsev (anatoly) for Python
# Discussion
## [[user/jkoenig/Java]]
## IRC, freenode, #hurd, 2013-12-19
<antrik_> teythoon_: I don't think wrapping libtrivfs etc. for guile
bindings is really desirable... for the lisp bindings, we agreed that
it's better to hook in at a lower level, and build more lispish
abstractions
<antrik> trivfs is a C framework; it probably doesn't map very well to
other languages -- especially non-imperative ones...
<antrik> (it is arguable whether trivfs is really a good abstraction even
for C... but that's another discussion :-) )
<antrik> ArneBab: same for Python bindings. when I suggested ignoring
libtrivfs etc., working around the pthread problem was just a side effect
-- the real goal has always been nicer abstraction
<anatoly> antrik: agree with you
<anatoly> antrik: about nicer abstractions
<teythoon_> antrik: I agree too, but wrapping libtrivfs is much easier
<teythoon_> otherwise, one needs to reimplement lots of stuff to get some
basic functionality
<teythoon_> like a mig that emits your language
<braunr> i agree with antrik too
<braunr> yes, the best would be mig handling multiple languages
[[!taglink open_issue_mig]].
<antrik> teythoon_: not exactly. for dynamic languages, code generation is
silly. just handle the marshalling on the fly. that's what the Lisp
bindings are doing (AFAIK)
<teythoon> antrik: ok, but you'd still need to parse the rpc definitions,
no?
<antrik> teythoon: yeah, you still need to parse the .defs -- unless we add
reflection to RPC interfaces...
<antrik> err, I mean introspection
|
