3 Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2008 Free software Foundation, Inc.
5 Permission is granted to anyone to make or distribute verbatim copies
6 of this document as received, in any medium, provided that the
7 copyright notice and permission notice are preserved,
8 and that the distributor grants the recipient permission
9 for further redistribution as permitted by this notice.
11 Permission is granted to distribute modified versions
12 of this document, or of portions of it,
13 under the above conditions, provided also that they
14 carry prominent notices stating who last changed them,
15 and that any new or changed statements about the activities
16 of the Free Software Foundation are approved by the Foundation.
19 What to Hack =========================================================
21 You can hack whatever you want, thank GNU.
23 However, to see what others have indicated as their interest (and avoid
24 potential wasteful duplication of effort), see file TODO. Note that
25 the version you find may be out of date; a CVS checkout is recommended:
26 see below for details (see also the files ANON-CVS and SNAPSHOTS).
28 It's also a good idea to join the guile-devel@gnu.org mailing list.
29 See http://www.gnu.org/software/guile/mail/mail.html for more info.
32 Hacking It Yourself ==================================================
34 When Guile is obtained from Git, a few extra steps must be taken
35 before the usual configure, make, make install. You will need to have
36 up-to-date versions of the tools as listed below, correctly installed.
38 Sometimes older or newer versions will work. (See below for versions
41 Then you must run the autogen.sh script, as described below.
43 The same procedure can be used to regenerate the files in released
44 versions of Guile. In that case the headers of the original generated
45 files (e.g., configure, Makefile.in, ltmain.sh) can be used to
46 identify which tool versions may be required.
48 Autoconf --- a system for automatically generating `configure'
49 scripts from templates which list the non-portable features a
50 program would like to use. Available in
51 "ftp://ftp.gnu.org/pub/gnu/autoconf"
53 Automake --- a system for automatically generating Makefiles that
54 conform to the (rather Byzantine) GNU coding standards. The
55 nice thing is that it takes care of hairy targets like 'make
56 dist' and 'make distclean', and automatically generates
57 Makefile dependencies. Automake is available in
58 "ftp://ftp.gnu.org/pub/gnu/automake"
60 libtool --- a system for managing the zillion hairy options needed
61 on various systems to produce shared libraries. Available in
62 "ftp://ftp.gnu.org/pub/gnu/libtool". Version 1.5.26 (or
63 later) is needed for correct AIX support.
65 gettext --- a system for rigging a program so that it can output its
66 messages in the local tongue. Guile presently only exports
67 the gettext functionality to Scheme, it does not use it
70 flex --- a scanner generator. It's probably not essential to have the
73 One false move and you will be lost in a little maze of automatically
74 generated files, all different.
76 Here is the authoritative list of tool/version/platform tuples that
77 have been known to cause problems, and a short description of the problem.
79 - automake 1.4 adds extraneous rules to the top-level Makefile if
80 you specify specific Makefiles to rebuild on the command line.
82 - automake 1.4-p4 (debian "1:1.4-p4-1.1") all platforms
83 automake "include" facility does not recognize filenames w/ "-".
85 - libtool 1.4 uses acconfig.h, which is deprecated by newest autoconf
86 (which constructs the equivalent through 3rd arg of AC_DEFINE forms).
88 - autoreconf from autoconf prior to 2.59 will run gettextize, which
89 will mess up the Guile tree.
94 Sample GDB Initialization File=========================================
96 Here is a sample .gdbinit posted by Bill Schottstaedt (modified to
97 use `set' instead of `call' in some places):
104 Executes (object->string arg)
109 call gdb_eval(gdb_result)
110 set gdb_print(gdb_result)
114 Executes (print (eval (read arg))): ge "(+ 1 2)" => 3
118 call g_help(scm_str2symbol($arg0), 20)
123 Prints help string for arg: gh "enved-target"
128 so in gdb if you see something useless like:
130 #32 0x081ae8f4 in scm_primitive_load (filename=1112137128) at load.c:129
132 You can get the file name with gp:
135 $1 = 0x40853fac "\"/home/bil/test/share/guile/1.5.0/ice-9/session.scm\""
138 Contributing Your Changes ============================================
140 - If you have put together a change that meets the coding standards
141 described below, we encourage you to submit it to Guile. Post your
142 patch to guile-devel@gnu.org.
144 - We prefer patches generated using 'git format-patch'.
146 - Provide a description in the commit message, like so:
148 1-line description of change
150 More extensive discussion of your change. Document why you are
153 * filename (function name): file specific change comments.
155 - For proper credit, also make sure you update the AUTHORS file
156 (for new files for which you've assigned copyright to the FSF), or
157 the THANKS file (for everything else).
160 Coding standards =====================================================
162 - As for any part of Project GNU, changes to Guile should follow the
163 GNU coding standards. The standards are available via anonymous FTP
164 from prep.ai.mit.edu, as /pub/gnu/standards/standards.texi and
167 - The Guile tree should compile without warnings under the following
168 GCC switches, which are the default in the current configure script:
170 -O2 -Wall -Wpointer-arith -Wmissing-prototypes
172 To make sure of this, you can use the --enable-error-on-warning option
173 to configure. This option will make GCC fail if it hits a warning.
175 Note that the warnings generated vary from one version of GCC to the
176 next, and from one architecture to the next (apparently). To provide
177 a concrete common standard, Guile should compile without warnings from
178 GCC 2.7.2.3 in a Red Hat 5.2 i386 Linux machine. Furthermore, each
179 developer should pursue any additional warnings noted by on their
180 compiler. This means that people using more stringent compilers will
181 have more work to do, and assures that everyone won't switch to the
182 most lenient compiler they can find. :)
184 - If you add code which uses functions or other features that are not
185 entirely portable, please make sure the rest of Guile will still
186 function properly on systems where they are missing. This usually
187 entails adding a test to configure.in, and then adding #ifdefs to your
188 code to disable it if the system's features are missing.
190 - The normal way of removing a function, macro or variable is to mark
191 it as "deprecated", keep it for a while, and remove it in a later
192 release. If a function or macro is marked as "deprecated" it
193 indicates that people shouldn't use it in new programs, and should try
194 to remove it in old. Make sure that an alternative exists unless it
195 is our purpose to remove functionality. Don't deprecate definitions
196 if it is unclear when they will be removed. (This is to ensure that a
197 valid way of implementing some functionality always exists.)
199 When deprecating a definition, always follow this procedure:
201 1. Mark the definition using
203 #if (SCM_DEBUG_DEPRECATED == 0)
207 or, for Scheme code, wrap it using
212 2. Make the deprecated code issue a warning when it is used, by using
213 scm_c_issue_deprecation_warning (in C) or issue-deprecation-warning
216 3. Write a comment at the definition explaining how a programmer can
217 manage without the deprecated definition.
219 4. Add an entry that the definition has been deprecated in NEWS and
220 explain what do do instead.
222 5. In file TODO, there is a list of releases with reminders about what
223 to do at each release. Add a reminder about the removal of the
224 deprecated defintion at the appropriate release.
226 - Write commit messages for functions written in C using the
227 functions' C names, and write entries for functions written in Scheme
228 using the functions' Scheme names. For example,
230 * foo.c: Moved scm_procedure_documentation from eval.c.
234 * foo.c: Moved procedure-documentation from eval.c.
236 Changes like adding this line are special:
238 SCM_PROC (s_map_in_order, "map-in-order", 2, 0, 1, scm_map);
240 Since the change here is about the name itself --- we're adding a new
241 alias for scm_map that guarantees the order in which we process list
242 elements, but we're not changing scm_map at all --- it's appropriate
243 to use the Scheme name in the commit message.
245 - Make sure you have papers from people before integrating their
246 changes or contributions. This is very frustrating, but very
247 important to do right. From maintain.texi, "Information for
248 Maintainers of GNU Software":
250 When incorporating changes from other people, make sure to follow the
251 correct procedures. Doing this ensures that the FSF has the legal
252 right to distribute and defend GNU software.
254 For the sake of registering the copyright on later versions ofthe
255 software you need to keep track of each person who makes significant
256 changes. A change of ten lines or so, or a few such changes, in a
257 large program is not significant.
259 *Before* incorporating significant changes, make sure that the person
260 has signed copyright papers, and that the Free Software Foundation has
263 If you receive contributions you want to use from someone, let me know
264 and I'll take care of the administrivia. Put the contributions aside
265 until we have the necessary papers.
267 Once you accept a contribution, be sure to keep the files AUTHORS and
270 - When you make substantial changes to a file, add the current year to
271 the list of years in the copyright notice at the top of the file.
273 - When you get bug reports or patches from people, be sure to list
277 Naming conventions =================================================
279 We use certain naming conventions to structure the considerable number
280 of global identifiers. All identifiers should be either all lower
281 case or all upper case. Syllables are separated by underscores `_'.
282 All non-static identifiers should start with scm_ or SCM_. Then might
283 follow zero or more syllables giving the category of the identifier.
284 The currently used category identifiers are
288 c,C - something with a interface suited for C use. This is used
289 to name functions that behave like Scheme primitives but
290 have a more C friendly calling convention.
292 i,I - internal to libguile. It is global, but not considered part
295 f - a SCM variable pointing to a Scheme function object.
297 F - a bit mask for a flag.
299 m - a macro transformer procedure
301 n,N - a count of something
303 s - a constant C string
305 k - a SCM variable pointing to a keyword.
307 sym - a SCM variable pointing to a symbol.
309 var - a SCM variable pointing to a variable object.
311 The follwing syllables also have a technical meaning:
313 str - this denotes a zero terminated C string
315 mem - a C string with an explicit count
318 See also the file `devel/names.text'.
321 Helpful hints ========================================================
323 - [From Mikael Djurfeldt] When working on the Guile internals, it is
324 quite often practical to implement a scheme-level procedure which
325 helps you examine the feature you're working on.
327 Examples of such procedures are: pt-size, debug-hand and
330 I've now put #ifdef GUILE_DEBUG around all such procedures, so that
331 they are not compiled into the "normal" Guile library. Please do the
332 same when you add new procedures/C functions for debugging purpose.
334 You can define the GUILE_DEBUG flag by passing --enable-guile-debug to
335 the configure script.
338 Jim Blandy, and others