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25 the version you find may be out of date; a CVS checkout is recommended: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 2.2 (or
63 later) is recommended (for correct AIX support, and correct
64 interaction with the Gnulib module for using libunistring).
66 gettext --- a system for rigging a program so that it can output its
67 messages in the local tongue. Guile presently only exports
68 the gettext functionality to Scheme, it does not use it
71 flex --- a scanner generator. It's probably not essential to have the
74 One false move and you will be lost in a little maze of automatically
75 generated files, all different.
77 Here is the authoritative list of tool/version/platform tuples that
78 have been known to cause problems, and a short description of the problem.
80 - automake 1.4 adds extraneous rules to the top-level Makefile if
81 you specify specific Makefiles to rebuild on the command line.
83 - automake 1.4-p4 (debian "1:1.4-p4-1.1") all platforms
84 automake "include" facility does not recognize filenames w/ "-".
86 - libtool 1.4 uses acconfig.h, which is deprecated by newest autoconf
87 (which constructs the equivalent through 3rd arg of AC_DEFINE forms).
89 - autoreconf from autoconf prior to 2.59 will run gettextize, which
90 will mess up the Guile tree.
92 - libtool 1.5.26 does not know that it should remove the -R options
93 that the Gnulib libunistring and havelib modules generate (because
94 gcc doesn't actually support -R).
99 Sample GDB Initialization File=========================================
101 Here is a sample .gdbinit posted by Bill Schottstaedt (modified to
102 use `set' instead of `call' in some places):
109 Executes (object->string arg)
114 call gdb_eval(gdb_result)
115 set gdb_print(gdb_result)
119 Executes (print (eval (read arg))): ge "(+ 1 2)" => 3
123 call g_help(scm_str2symbol($arg0), 20)
128 Prints help string for arg: gh "enved-target"
133 so in gdb if you see something useless like:
135 #32 0x081ae8f4 in scm_primitive_load (filename=1112137128) at load.c:129
137 You can get the file name with gp:
140 $1 = 0x40853fac "\"/home/bil/test/share/guile/1.5.0/ice-9/session.scm\""
143 Contributing Your Changes ============================================
145 - If you have put together a change that meets the coding standards
146 described below, we encourage you to submit it to Guile. Post your
147 patch to guile-devel@gnu.org.
149 - We prefer patches generated using 'git format-patch'.
151 - Provide a description in the commit message, like so:
153 1-line description of change
155 More extensive discussion of your change. Document why you are
158 * filename (function name): file specific change comments.
160 - For proper credit, also make sure you update the AUTHORS file
161 (for new files for which you've assigned copyright to the FSF), or
162 the THANKS file (for everything else).
165 Coding standards =====================================================
167 - As for any part of Project GNU, changes to Guile should follow the
168 GNU coding standards. The standards are available via anonymous FTP
169 from prep.ai.mit.edu, as /pub/gnu/standards/standards.texi and
172 - The Guile tree should compile without warnings under the following
173 GCC switches, which are the default in the current configure script:
175 -O2 -Wall -Wpointer-arith -Wmissing-prototypes
177 To make sure of this, you can use the --enable-error-on-warning option
178 to configure. This option will make GCC fail if it hits a warning.
180 Note that the warnings generated vary from one version of GCC to the
181 next, and from one architecture to the next (apparently). To provide
182 a concrete common standard, Guile should compile without warnings from
183 GCC 2.7.2.3 in a Red Hat 5.2 i386 Linux machine. Furthermore, each
184 developer should pursue any additional warnings noted by on their
185 compiler. This means that people using more stringent compilers will
186 have more work to do, and assures that everyone won't switch to the
187 most lenient compiler they can find. :)
189 - If you add code which uses functions or other features that are not
190 entirely portable, please make sure the rest of Guile will still
191 function properly on systems where they are missing. This usually
192 entails adding a test to configure.in, and then adding #ifdefs to your
193 code to disable it if the system's features are missing.
195 - The normal way of removing a function, macro or variable is to mark
196 it as "deprecated", keep it for a while, and remove it in a later
197 release. If a function or macro is marked as "deprecated" it
198 indicates that people shouldn't use it in new programs, and should try
199 to remove it in old. Make sure that an alternative exists unless it
200 is our purpose to remove functionality. Don't deprecate definitions
201 if it is unclear when they will be removed. (This is to ensure that a
202 valid way of implementing some functionality always exists.)
204 When deprecating a definition, always follow this procedure:
206 1. Mark the definition using
208 #if (SCM_DEBUG_DEPRECATED == 0)
212 or, for Scheme code, wrap it using
217 2. Make the deprecated code issue a warning when it is used, by using
218 scm_c_issue_deprecation_warning (in C) or issue-deprecation-warning
221 3. Write a comment at the definition explaining how a programmer can
222 manage without the deprecated definition.
224 4. Add an entry that the definition has been deprecated in NEWS and
225 explain what do do instead.
227 5. In file TODO, there is a list of releases with reminders about what
228 to do at each release. Add a reminder about the removal of the
229 deprecated defintion at the appropriate release.
231 - Write commit messages for functions written in C using the
232 functions' C names, and write entries for functions written in Scheme
233 using the functions' Scheme names. For example,
235 * foo.c: Moved scm_procedure_documentation from eval.c.
239 * foo.c: Moved procedure-documentation from eval.c.
241 Changes like adding this line are special:
243 SCM_PROC (s_map_in_order, "map-in-order", 2, 0, 1, scm_map);
245 Since the change here is about the name itself --- we're adding a new
246 alias for scm_map that guarantees the order in which we process list
247 elements, but we're not changing scm_map at all --- it's appropriate
248 to use the Scheme name in the commit message.
250 - Make sure you have papers from people before integrating their
251 changes or contributions. This is very frustrating, but very
252 important to do right. From maintain.texi, "Information for
253 Maintainers of GNU Software":
255 When incorporating changes from other people, make sure to follow the
256 correct procedures. Doing this ensures that the FSF has the legal
257 right to distribute and defend GNU software.
259 For the sake of registering the copyright on later versions ofthe
260 software you need to keep track of each person who makes significant
261 changes. A change of ten lines or so, or a few such changes, in a
262 large program is not significant.
264 *Before* incorporating significant changes, make sure that the person
265 has signed copyright papers, and that the Free Software Foundation has
268 If you receive contributions you want to use from someone, let me know
269 and I'll take care of the administrivia. Put the contributions aside
270 until we have the necessary papers.
272 Once you accept a contribution, be sure to keep the files AUTHORS and
275 - When you make substantial changes to a file, add the current year to
276 the list of years in the copyright notice at the top of the file.
278 - When you get bug reports or patches from people, be sure to list
282 Naming conventions =================================================
284 We use certain naming conventions to structure the considerable number
285 of global identifiers. All identifiers should be either all lower
286 case or all upper case. Syllables are separated by underscores `_'.
287 All non-static identifiers should start with scm_ or SCM_. Then might
288 follow zero or more syllables giving the category of the identifier.
289 The currently used category identifiers are
293 c,C - something with a interface suited for C use. This is used
294 to name functions that behave like Scheme primitives but
295 have a more C friendly calling convention.
297 i,I - internal to libguile. It is global, but not considered part
300 f - a SCM variable pointing to a Scheme function object.
302 F - a bit mask for a flag.
304 m - a macro transformer procedure
306 n,N - a count of something
308 s - a constant C string
310 k - a SCM variable pointing to a keyword.
312 sym - a SCM variable pointing to a symbol.
314 var - a SCM variable pointing to a variable object.
316 The follwing syllables also have a technical meaning:
318 str - this denotes a zero terminated C string
320 mem - a C string with an explicit count
323 See also the file `devel/names.text'.
326 Helpful hints ========================================================
328 - [From Mikael Djurfeldt] When working on the Guile internals, it is
329 quite often practical to implement a scheme-level procedure which
330 helps you examine the feature you're working on.
332 Examples of such procedures are: pt-size, debug-hand and
335 I've now put #ifdef GUILE_DEBUG around all such procedures, so that
336 they are not compiled into the "normal" Guile library. Please do the
337 same when you add new procedures/C functions for debugging purpose.
339 You can define the GUILE_DEBUG flag by passing --enable-guile-debug to
340 the configure script.
343 Jim Blandy, and others