1 \input texinfo @c -*-texinfo-*-
3 @setfilename 8sync.info
7 Copyright @copyright{} 2015 Christopher Allan Webber @email{cwebber@@dustycloud.org}
11 Permission is granted to copy, distribute and/or modify this document
12 under the terms of the GNU Free Documentation License, Version 1.3
13 or any later version published by the Free Software Foundation;
14 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
15 A copy of the license is included in the section entitled ``GNU
16 Free Documentation License''.
18 A copy of the license is also available from the Free Software
19 Foundation Web site at @url{http://www.gnu.org/licenses/fdl.html}.
21 Altenately, this document is also available under the Lesser General
22 Public License, version 3 or later, as published by the Free Software
25 A copy of the license is also available from the Free Software
26 Foundation Web site at @url{http://www.gnu.org/licenses/lgpl.html}.
33 @subtitle Using 8sync, an asynchronous event loop for Guile
34 @author Christopher Allan Webber
36 @vskip 0pt plus 1filll
40 @c Output the table of the contents at the beginning.
50 @c Generate the nodes for this menu with `C-c C-u C-m'.
53 @c Update all node entries with `C-c C-u C-n'.
54 @c Insert new nodes with `C-c C-c n'.
59 * Copying This Manual::
66 8sync's goal is to make asynchronous programming easy.
67 If you've worked with most other asynchronous programming environments,
68 you know that it generally isn't.
69 Usually asynchronous programming involves entering some sort of
71 Some nicer environments like Asyncio for Python provide generator-based
72 coroutines, but even these require a lot of work to carefully line up.
74 Coding in 8sync, on the other hand, looks almost entirely like coding
76 This is because 8sync makes great use of a cool feature in Guile called
77 ``delimited continuations'' to power natural-feeling coroutines.
78 Because of this, you can invoke your asynchronous code with a small wrapper
79 around it, and that code will pop off to complete whatever other task it
80 needs to do, and resume your function when it's ready passing back the
82 (No need to manually chain the coroutines together, and no callback hell at
85 Now that's pretty cool!
87 @node Acknowledgements
88 @chapter Acknowledgements
90 8sync has a number of inspirations:
94 @uref{https://docs.python.org/3.5/library/asyncio.html, asyncio}
95 for Python provides a nice asynchronous programming environment, and
96 makes great use of generator-style coroutines.
97 It's a bit more difficult to work with than 8sync (or so thinks the author)
98 because you have to ``line up'' the coroutines.
101 @uref{http://dthompson.us/pages/software/sly.html, Sly}
102 by David Thompson is an awesome functional reactive game programming
104 If you want to write graphical games, Sly is almost certainly a better choice
106 Thanks to David for being very patient in explaining tough concepts;
107 experience on hacking Sly greatly informed 8sync's development.
108 (Check out Sly, it rocks!)
111 Reading @uref{https://mitpress.mit.edu/sicp/, SICP}, particularly
112 @uref{https://mitpress.mit.edu/sicp/full-text/book/book-Z-H-19.html#%_chap_3,
113 Chapter 3's writings on concurrent systems},
114 greatly informed 8sync's design.
117 Finally, @uref{https://docs.python.org/3.5/library/asyncio.html, XUDD}
118 was an earlier ``research project'' that preceeded 8sync.
119 It attempted to bring an actor model system to Python.
120 However, the author eventually grew frustrated with some of Python's
121 limitations, fell in love with Guile, and well... now we have 8sync, which
122 is much more general anyway.
126 The motivation to build 8sync came out of
127 @uref{https://lists.gnu.org/archive/html/guile-devel/2015-10/msg00015.html,
129 at the FSF 30th party between Mark Weaver, David Thompson, Andrew
130 Engelbrecht, and Christopher Allan Webber over how to build
131 an asynchronous event loop for Guile and just what would be needed.
133 A little over a month after that, hacking on 8sync began!
136 @node 8sync's license and general comments on copyleft
137 @chapter 8sync's license and general comments on copyleft
139 8sync is released under the GNU LGPL (Lesser General Public License),
140 version 3 or later, as published by the Free Software Foundation.
141 The short version of this is that if you distribute a modifications to
142 8sync, whether alone or in some larger combination, must release the
143 corresponding source code.
144 A program which uses this library, if distributed without source code,
145 must also allow relinking with a modified version of this library.
146 In general, it is best to contribute them back to 8sync under the same terms;
147 we'd appreciate any enhancements or fixes to be contributed upstream to
149 (This is an intentional oversimplification for brevity, please read the LGPL
150 for the precise terms.)
152 This usage of the LGPL helps us ensure that 8sync and derivatives of
153 8sync as a library will remain free.
154 Though it is not a requirement, we request you use 8sync to build free
155 software rather than use it to contribute to the growing world of
156 proprietary software.
158 The choice of the LGPL for 8sync was a strategic one, though in general,
159 we encourage stronger copyleft.
160 (For more thinking on this position, see
161 @uref{https://www.gnu.org/licenses/why-not-lgpl.html,
162 Why you shouldn't use the Lesser GPL for your next library}.)
164 In particular, if you are building a library or application that uses
165 8sync in some useful way, consider releasing your program under the GNU
167 In a world where more and more software is locked down, where software is used
168 to restrict users, we could use every chance we can get to provide
169 protections so that software which is free remains free, and encourages even
170 more software freedom to be built upon it.
172 So to answer the question, ``Can I build a proprietary program on top of
173 8sync?'' our response is
174 ``Yes, but please don't.
175 Choose to release your software under a freedom-respecting license.
176 And help us turn the tide towards greater software freedom...
177 consider a strong copyleft license!''
180 @node Copying This Manual
181 @appendix Copying This Manual
183 This manual is licensed under the GNU Free Documentation License, with
184 no invariant sections. At your option, it is also available under the
185 GNU Lesser General Public License, as published by the Free Software
186 Foundation, version 3 or any later version.
189 * GNU Free Documentation License:: License for copying this manual.
192 @c Get fdl.texi from http://www.gnu.org/licenses/fdl.html
193 @node GNU Free Documentation License
194 @section GNU Free Documentation License
206 @c 8sync.texi ends here