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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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Boost Library Requirements and Guidelines
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<img src="../boost.png" alt="boost.png (6897 bytes)" width="277"
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<a href="../index.htm"><font face="Arial" color=
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"#FFFFFF"><big>Home</big></font></a>
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<a href="../libs/libraries.htm"><font face="Arial" color=
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"#FFFFFF"><big>Libraries</big></font></a>
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<a href="../people/people.htm"><font face="Arial" color=
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<a href="faq.htm"><font face="Arial" color=
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<a href="index.htm"><font face="Arial" color=
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"#FFFFFF"><big>More</big></font></a>
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</td>
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</table>
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<h1 align="left">
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Boost Library Requirements and Guidelines
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</h1>
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<p align="left">
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<a href="#Introduction">Introduction</a><br>
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<a href="#Requirements">Requirements</a><br>
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<a href="#License">License requirements</a><br>
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<a href="#Portability">Portability requirements</a><br>
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<a href="#Ownership">Ownership</a><br>
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<a href="#Guidelines">Guidelines</a><br>
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<a href="#Design_and_Programming">Design and
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programming</a><br>
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<a href="#Directory_structure">Directory structure and
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filenames</a><br>
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<a href="#Naming_consistency">Naming
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consistency</a><br>
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<a href="#Documentation">Documentation</a><br>
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<a href="#Rationale">Rationale</a><br>
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<a href=
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"#Exception-specification">Exception-specification rationale</a><br>
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<a href="#Naming">Naming conventions rationale</a><br>
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<a href="#code_fonts">Source code fonts
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rationale</a><br>
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<a href="#Tabs">Tabs rationale</a><br>
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<a href="#JavaScript">ECMAScript/JavaScript
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rationale</a><br>
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<a href="#Rationale_rationale">Rationale
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rationale</a><br>
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<a href="#Acknowledgements">Acknowledgements
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rationale</a>
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</p>
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<h2 align="left">
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<a name="Introduction" id="Introduction">Introduction</a>
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</h2>
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<p align="left">
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This page describes requirements and guidelines for the content of a
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library submitted to Boost.
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</p>
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<p align="left">
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See the <a href="submission_process.htm">Boost Library Submission
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Process</a> page for a description of the process involved.
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</p>
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<h2 align="left">
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<a name="Requirements" id="Requirements">Requirements</a>
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</h2>
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<p>
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To avoid the frustration and wasted time of a proposed library being
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rejected, it must meets these requirements:
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</p>
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<ul>
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<li>The license must meet the <a href="#License">license requirements</a>
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below. Restricted licenses like the GPL and LGPL are not acceptable.
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</li>
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<li>The copyright <a href="#Ownership">ownership</a> must be clear.
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</li>
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<li>The library must be generally useful and not restricted to a narrow
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problem domain.
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</li>
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<li>The library must meet the <a href="#Portability">portability
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requirements</a> below.
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</li>
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<li>The library must come reasonably close to meeting the <a href=
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"#Guidelines">Guidelines</a> below.
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<ul>
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<li>
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<a href="#Design_and_Programming">Design and Programming</a>
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</li>
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<li>
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<a href="#Directory_structure">Directory Structure</a>
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</li>
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<li>
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<a href="#Documentation">Documentation</a>
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</li>
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</ul>
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</li>
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<li>The author must be willing to participate in discussions on the mailing
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list, and to refine the library accordingly.
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</li>
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</ul>
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<p>
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There's no requirement that an author read the mailing list for a time
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before making a submission. It has been noted, however, that submissions
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which begin "I just started to read this mailing list ..." seem to fail,
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often embarrassingly.
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</p>
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<h3 align="left">
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<a name="License" id="License">License</a> requirements
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</h3>
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<p>
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The preferred way to meet the license requirements is to use the <a href=
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"../LICENSE_1_0.txt">Boost Software License</a>. See <a href=
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"license_info.html">license information</a>. If for any reason you do not
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intend to use the Boost Software License, please discuss the issues on the
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Boost <a href="mailing_lists.htm#main">developers mailing list</a> first.
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</p>
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<p>
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The license requirements:
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</p>
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<ul>
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<li>Must be simple to read and understand.
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</li>
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<li>Must grant permission without fee to copy, use and modify the software
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for any use (commercial and non-commercial).
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</li>
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<li>Must require that the license appear on all copies of the software
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source code.
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</li>
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<li>Must not require that the license appear with executables or other
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binary uses of the library.
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</li>
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<li>Must not require that the source code be available for execution or
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other binary uses of the library.
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</li>
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<li>May restrict the use of the name and description of the library to the
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standard version found on the Boost web site.
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</li>
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</ul>
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<h3 align="left">
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<a name="Portability" id="Portability">Portability</a> requirements
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</h3>
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<ul>
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<li>
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<p align="left">
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A library's interface must portable and not restricted to a particular
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compiler or operating system.
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</p>
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</li>
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<li>
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<p align="left">
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A library's implementation must if possible be portable and not
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restricted to a particular compiler or operating system. If a
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portable implementation is not possible, non-portable constructions are
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acceptable if reasonably easy to port to other environments, and
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implementations are provided for at least two popular operating systems
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(such as UNIX and Windows).
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</p>
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</li>
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<li>
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<p align="left">
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There is no requirement that a library run on C++ compilers which do
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not conform to the ISO standard.
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</p>
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</li>
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<li>
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<p align="left">
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There is no requirement that a library run on any particular C++
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compiler. Boost contributors often try to ensure their libraries
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work with popular compilers. The boost/config.hpp <a href=
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"../libs/config/config.htm">configuration header</a> is the preferred
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mechanism for working around compiler deficiencies.
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</p>
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</li>
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</ul>
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<p align="left">
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Since there is no absolute way to prove portability, many boost submissions
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demonstrate practical portability by compiling and executing correctly with
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two different C++ compilers, often under different operating systems.
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Otherwise reviewers may disbelieve that porting is in fact practical.
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</p>
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<h3 align="left">
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<a name="Ownership" id="Ownership">Ownership</a>
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</h3>
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<p align="left">
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Are you sure you own the library you are thinking of
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submitting? "How to Copyright Software" by MJ Salone, Nolo
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Press, 1990 says:
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</p>
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<blockquote>
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<p align="left">
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Doing work on your own time that is very similar to programming you do
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for your employer on company time can raise nasty legal problems.
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In this situation, it's best to get a written release from your employer
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in advance.
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</p>
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</blockquote>
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<p align="left">
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Place a copyright notice in all the important files you submit. Boost won't
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accept libraries without clear copyright information.
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</p>
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<h2 align="left">
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<a name="Guidelines" id="Guidelines">Guidelines</a>
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</h2>
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<p align="left">
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Please use these guidelines as a checklist for preparing the content a
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library submission. Not every guideline applies to every library, but
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a reasonable effort to comply is expected.
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</p>
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<h3>
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<a name="Design_and_Programming" id="Design_and_Programming">Design and
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Programming</a>
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</h3>
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<ul>
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<li>Aim first for clarity and correctness; optimization should be only a
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secondary concern in most Boost libraries.
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</li>
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</ul>
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<ul>
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<li>Aim for ISO Standard C++. Than means making effective use of the
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standard features of the language, and avoiding non-standard compiler
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extensions. It also means using the C++ Standard Library where applicable.
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</li>
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</ul>
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<ul>
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<li>Headers should be good neighbors. See the <a href="header.htm">header
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policy</a>. See <a href="#Naming_consistency">Naming consistency</a>.
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</li>
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</ul>
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<ul>
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<li>Follow quality programming practices. See, for example, "Effective C++"
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2nd Edition, and "More Effective C++", both by Scott Meyers, published by
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Addison Wesley.
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</li>
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</ul>
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<ul>
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<li>Use the C++ Standard Library or other Boost libraries, but only when
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the benefits outweigh the costs. Do not use libraries other than the
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C++ Standard Library or Boost. See <a href="library_reuse.htm">Library
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reuse</a>.
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</li>
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</ul>
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<ul>
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<li>Read <a href="imp_vars.htm">Implementation Variation</a> to see how to
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supply performance, platform, or other implementation variations.
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</li>
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</ul>
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<ul>
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<li>Read the <a href="separate_compilation.html">guidelines for libraries
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with separate source</a> to see how to ensure that compiled link libraries
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meet user expectations.
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</li>
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</ul>
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<ul>
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<li>Use the naming conventions of the C++ Standard Library (See <a href=
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"#Naming">Naming conventions rationale</a>):<br>
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|
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<ul>
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<li>Names (except as noted below) should be all lowercase, with words
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separated by underscores.
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</li>
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<li>Acronyms should be treated as ordinary names (e.g.
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<code>xml_parser</code> instead of <code>XML_parser</code>).
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</li>
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<li>Template parameter names begin with an uppercase letter.
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</li>
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<li>Macro (gasp!) names all uppercase and begin with BOOST_.
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</li>
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</ul>
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</li>
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</ul>
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<ul>
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<li>Choose meaningful names - explicit is better than implicit, and
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readability counts. There is a strong preference for clear and descriptive
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names, even if lengthy.
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</li>
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</ul>
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<ul>
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<li>Use exceptions to report errors where appropriate, and write code that
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is safe in the face of exceptions.
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</li>
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</ul>
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<ul>
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<li>Avoid exception-specifications. See <a href="#Exception-specification">
|
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exception-specification rationale</a>.
|
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</li>
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</ul>
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<ul>
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<li>Provide sample programs or confidence tests so potential users can see
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how to use your library.
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</li>
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</ul>
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<ul>
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<li>Provide a regression test program or programs which follow the
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<a href="test_policy.htm">Test Policies and Protocols</a>.
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</li>
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</ul>
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<ul>
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<li>Although some boost members use proportional fonts, tabs, and
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unrestricted line lengths in their own code, boost's widely distributed
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source code should follow more conservative guidelines:
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<ul>
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<li>Use fixed-width fonts. See <a href="#code_fonts">fonts
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rationale</a>.
|
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</li>
|
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<li>Use spaces rather than tabs. See <a href="#Tabs">tabs
|
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rationale</a>.
|
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</li>
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<li>Limit line lengths to 80 characters.
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</li>
|
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</ul>
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</li>
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</ul>
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<ul>
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<li>End all documentation files (HTML or otherwise) with a copyright
|
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message and a licensing message. See <a href="license_info.html">license
|
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information</a> page for the preferred form.
|
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</li>
|
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</ul>
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<ul>
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<li>Begin all source files (including programs, headers, scripts, etc.)
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with:<br>
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|
|
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<ul>
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<li>A comment line describing the contents of the file.<br>
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</li>
|
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<li>Comments describing copyright and licensing: again, the preferred
|
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form is indicated in the <a href="license_info.html">license
|
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information</a> page<br>
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<br>
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Note that developers should not provide a copy of
|
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<code>LICENSE_1_0.txt</code> with their libraries: Boost
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distributions already include a copy in the Boost root directory.<br>
|
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</li>
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<li>A comment line referencing your library on the Boost web site. For
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example:<br>
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<br>
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<code>// See http://www.boost.org/libs/foo/ for library home
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page.</code><br>
|
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<br>
|
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where <code>foo</code> is the directory name (see below) for the
|
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library. As well as aiding users who come across a Boost file
|
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detached from its documentation, some of Boost's automatic tools
|
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depend on this comment to identify which library header files belong
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to.
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</li>
|
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</ul>
|
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</li>
|
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|
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</ul>
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<ul>
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<li>Make sure your code compiles in the presence of the <code>min()</code>
|
|
and <code>max()</code> macros. Some platform headers define
|
|
<code>min()</code> and <code>max()</code> macros which cause some common
|
|
C++ constructs to fail to compile. Some simple tricks can protect your code
|
|
from inappropriate macro substitution:<br>
|
|
|
|
|
|
<ul>
|
|
<li>If you want to call <code>std::min()</code> or
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<code>std::max()</code>:<br>
|
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|
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<ul>
|
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<li>If you do not require argument-dependent look-up, use
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<code>(std::min)(a,b)</code>.
|
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</li>
|
|
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<li style="list-style: none">
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|
<br>
|
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</li>
|
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<li>If you do require argument-dependent look-up, you should:
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</li>
|
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<li style="list-style: none">
|
|
<br>
|
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<ul>
|
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<li>
|
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|
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<code>#include <boost/config.hpp></code>
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</li>
|
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<li>Use <code>BOOST_USING_STD_MIN();</code> to bring
|
|
<code>std::min()</code> into the current scope.
|
|
</li>
|
|
<li>Use <code>min BOOST_PREVENT_MACRO_SUBSTITUTION
|
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(a,b);</code> to make an argument-dependent call to
|
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<code>min(a,b)</code>.
|
|
</li>
|
|
|
|
</ul>
|
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</li>
|
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</ul>
|
|
</li>
|
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<li style="list-style: none">
|
|
<br>
|
|
</li>
|
|
<li>If you want to call
|
|
<code>std::numeric_limits<int>::max()</code>, use
|
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<code>(std::numeric_limits<int>::max)()</code> instead.
|
|
</li>
|
|
|
|
<li style="list-style: none">
|
|
<br>
|
|
</li>
|
|
<li>If you want to call a <code>min()</code> or <code>max()</code>
|
|
member function, instead to doing <code>obj.min()</code>, use
|
|
<code>(obj.min)()</code>.<br>
|
|
|
|
</li>
|
|
<li style="list-style: none">
|
|
<br>
|
|
</li>
|
|
<li>If you want to declare or define a function or a member function
|
|
named <code>min</code> or <code>max</code>, then you must use the
|
|
<code>BOOST_PREVENT_MACRO_SUBSTITUTION</code> macro. Instead of writing
|
|
<code>int min() { return 0; }</code> you should write <code>int min
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|
BOOST_PREVENT_MACRO_SUBSTITUTION () { return 0; }</code><br>
|
|
|
|
This is true regardless if the function is a free (namespace scope)
|
|
function, a member function or a static member function, and it
|
|
applies for the function declaration as well as for the function
|
|
definition.<br>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<h3>
|
|
<a name="Directory_structure" id="Directory_structure">Directory
|
|
Structure</a> and Filenames
|
|
</h3>
|
|
|
|
<ul>
|
|
<li>File and directory names must contain only <b>lowercase</b> ASCII
|
|
letters , numbers, underscores, and a period. Leading character must
|
|
be alphabetic. Maximum length 31. Only a single period is permitted.
|
|
These requirements ensure file and directory names are relatively portable.
|
|
</li>
|
|
<li>Files intended to be processed by a C++ compiler as part of a
|
|
translation unit should have <b>a three-letter filename extension ending in
|
|
"pp"</b>. Other files should <i>not</i> use extensions ending in "pp". This
|
|
convention makes it easy to identify all of the C++ source in Boost.
|
|
</li>
|
|
|
|
<li>All libraries have at their highest level a primary directory named for
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|
the particular library. See <a href="#Naming_consistency">Naming
|
|
consistency</a>. The primary directory may have sub-directories.
|
|
</li>
|
|
<li>For very simple libraries implemented entirely within the library
|
|
header, all files go in the primary directory (except headers, which go in
|
|
the boost header directory).
|
|
</li>
|
|
</ul>
|
|
<blockquote>
|
|
<p>
|
|
<b>Boost standard sub-directory names</b>
|
|
|
|
</p>
|
|
<table border="1" cellpadding="5">
|
|
<tr>
|
|
<td>
|
|
<b>Sub-directory</b>
|
|
</td>
|
|
<td>
|
|
<b>Contents</b>
|
|
|
|
</td>
|
|
<td>
|
|
<b>Required</b>
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
<code>build</code>
|
|
|
|
</td>
|
|
<td>
|
|
Library build files such as a Jamfile.
|
|
</td>
|
|
<td>
|
|
If any build files.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
|
|
<code>doc</code>
|
|
</td>
|
|
<td>
|
|
Documentation (HTML) files.
|
|
</td>
|
|
<td>
|
|
If several doc files.
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td>
|
|
<code>example</code>
|
|
</td>
|
|
<td>
|
|
Sample program files.
|
|
</td>
|
|
<td>
|
|
If several sample files.
|
|
</td>
|
|
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
<code>src</code>
|
|
</td>
|
|
<td>
|
|
Source files which must be compiled to build the library.
|
|
</td>
|
|
|
|
<td>
|
|
If any source files.
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
<code>test</code>
|
|
</td>
|
|
<td>
|
|
|
|
Regression or other test programs or scripts.
|
|
</td>
|
|
<td>
|
|
If several test files.
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
</blockquote>
|
|
<h4>
|
|
<a name="Redirection" id="Redirection">Redirection</a>
|
|
|
|
</h4>
|
|
<p>
|
|
The primary directory should always contain a file named index.html (or
|
|
index.htm). Authors have requested this so that they can publish URL's in
|
|
the form <i>http://www.boost.org/libs/lib-name</i> with the assurance a
|
|
documentation reorganization won't invalidate the URL. Boost's internal
|
|
tools are also simplified by knowing that a library's documentation is
|
|
always reachable via the simplified URL.
|
|
</p>
|
|
<p>
|
|
If the documentation is in a doc sub-directory, the primary directory
|
|
index.html file should just do an automatic redirection to the doc
|
|
subdirectory:
|
|
</p>
|
|
<blockquote>
|
|
|
|
<pre>
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="refresh" content="0; URL=doc/index.html">
|
|
</head>
|
|
<body>
|
|
Automatic redirection failed, please go to
|
|
<a href="doc/index.html">doc/index.html</a>
|
|
|
|
</body>
|
|
</html>
|
|
</pre>
|
|
</blockquote>
|
|
<h3>
|
|
<a name="Naming_consistency">Naming consistency</a>
|
|
</h3>
|
|
<p>
|
|
As library developers and users have gained experience with Boost, the
|
|
following consistent naming approach has come to be viewed as very helpful,
|
|
particularly for larger libraries that need their own header subdirectories
|
|
and namespaces.
|
|
</p>
|
|
|
|
<p>
|
|
Here is how it works. The library is given a name that describes the
|
|
contents of the library. Cryptic abbreviations are strongly discouraged.
|
|
Following the practice of the C++ Standard Library, names are usually
|
|
singular rather than plural. For example, a library dealing with file
|
|
systems might chose the name "filesystem", but not "filesystems", "fs" or
|
|
"nicecode".
|
|
</p>
|
|
<ul>
|
|
<li>The library's primary directory (in parent <i>boost-root/libs</i>) is
|
|
given that same name. For example,
|
|
<i>boost-root/libs/filesystem</i>.<br>
|
|
|
|
|
|
</li>
|
|
<li>The library's primary header directory (in parent
|
|
<i>boost-root/boost</i>) is given that same name. For example,
|
|
<i>boost-root/boost/filesystem</i>.<br>
|
|
|
|
</li>
|
|
<li>The library's primary namespace (in parent <i>::boost</i>) is given
|
|
that same name, except when there's a component with that name (e.g.,
|
|
<i>boost::tuple</i>), in which case the namespace name is pluralized. For
|
|
example, <i>::boost::filesystem</i>.
|
|
</li>
|
|
|
|
</ul>
|
|
<p>
|
|
When documenting Boost libraries, follow these conventions (see also the
|
|
following section of this document):
|
|
</p>
|
|
<ul>
|
|
<li>The library name is set in roman type.
|
|
</li>
|
|
<li>The library name is capitalized.
|
|
</li>
|
|
<li>A period between "Boost" and the library name (e.g., Boost.Bind) is
|
|
used if and only if the library name is not followed by the word "library".
|
|
</li>
|
|
|
|
<li>The word "library" is not part of the library name and is therefore
|
|
lowercased.
|
|
</li>
|
|
</ul>
|
|
<p>
|
|
Here are a few examples of how to apply these conventions:
|
|
</p>
|
|
<ul>
|
|
<li>Boost.Bind was written by Peter Dimov.
|
|
</li>
|
|
<li>The Boost Bind library was written by Peter Dimov.
|
|
</li>
|
|
|
|
<li>I regularly use Bind, a Boost library written by Peter Dimov.
|
|
</li>
|
|
</ul>
|
|
<h3>
|
|
<a name="Documentation" id="Documentation">Documentation</a>
|
|
</h3>
|
|
<p>
|
|
Even the simplest library needs some documentation; the amount should be
|
|
proportional to the need. The documentation should assume the readers
|
|
have a basic knowledge of C++, but are not necessarily experts.
|
|
</p>
|
|
|
|
<p>
|
|
The format for documentation should be HTML, and should not require an
|
|
advanced browser or server-side extensions. Style sheets are acceptable.
|
|
ECMAScript/JavaScript is not acceptable. The documentation entry point
|
|
should always be a file named index.html or index.htm; see <a href=
|
|
"#Redirection">Redirection</a>.
|
|
</p>
|
|
<p>
|
|
There is no single right way to do documentation. HTML documentation is
|
|
often organized quite differently from traditional printed documents.
|
|
Task-oriented styles differ from reference oriented styles. In the end, it
|
|
comes down to the question: Is the documentation sufficient for the
|
|
mythical "average" C++ programmer to use the library successfully?
|
|
</p>
|
|
<p>
|
|
Appropriate topics for documentation often include:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>General introduction to the library.
|
|
</li>
|
|
<li>Description of each class.
|
|
</li>
|
|
<li>Relationship between classes.
|
|
</li>
|
|
<li>For each function, as applicable, description, requirements
|
|
(preconditions), effects, post-conditions, returns, and throws.
|
|
</li>
|
|
<li>Discussion of error detection and recovery strategy.
|
|
</li>
|
|
|
|
<li>How to use including description of typical uses.
|
|
</li>
|
|
<li>How to compile and link.
|
|
</li>
|
|
<li>How to test.
|
|
</li>
|
|
<li>Version or revision history.
|
|
</li>
|
|
<li>Rationale for design decisions. See <a href=
|
|
"#Rationale">Rationale rationale</a>.
|
|
</li>
|
|
|
|
<li>Acknowledgements. See <a href="#Acknowledgements">Acknowledgments
|
|
rationale.</a>
|
|
</li>
|
|
</ul>
|
|
<p>
|
|
If you need more help with how to write documentation you can check out the
|
|
article on <a href="writingdoc/index.html">Writing Documentation for
|
|
Boost</a>.
|
|
</p>
|
|
|
|
<h2>
|
|
<a name="Rationale" id="Rationale">Rationale</a>
|
|
</h2>
|
|
<p>
|
|
Rationale for some of the requirements and guidelines follows.
|
|
</p>
|
|
<hr>
|
|
<h3>
|
|
<a name="Exception-specification" id=
|
|
"Exception-specification">Exception-specification</a> rationale
|
|
</h3>
|
|
|
|
<p>
|
|
Exception specifications [ISO 15.4] are sometimes coded to indicate what
|
|
exceptions may be thrown, or because the programmer hopes they will
|
|
improved performance. But consider the following member from a smart
|
|
pointer:
|
|
</p>
|
|
<pre>
|
|
T& operator*() const throw() { return *ptr; }
|
|
</pre>
|
|
<p>
|
|
This function calls no other functions; it only manipulates fundamental
|
|
data types like pointers Therefore, no runtime behavior of the
|
|
exception-specification can ever be invoked. The function is
|
|
completely exposed to the compiler; indeed it is declared inline Therefore,
|
|
a smart compiler can easily deduce that the functions are incapable of
|
|
throwing exceptions, and make the same optimizations it would have made
|
|
based on the empty exception-specification. A "dumb" compiler, however, may
|
|
make all kinds of pessimizations.
|
|
</p>
|
|
|
|
<p>
|
|
For example, some compilers turn off inlining if there is an
|
|
exception-specification. Some compilers add try/catch blocks. Such
|
|
pessimizations can be a performance disaster which makes the code unusable
|
|
in practical applications.
|
|
</p>
|
|
<p>
|
|
Although initially appealing, an exception-specification tends to have
|
|
consequences that require <b>very</b> careful thought to understand. The
|
|
biggest problem with exception-specifications is that programmers use them
|
|
as though they have the effect the programmer would like, instead of the
|
|
effect they actually have.
|
|
</p>
|
|
<p>
|
|
|
|
A non-inline function is the one place a "throws nothing"
|
|
exception-specification may have some benefit with some compilers.
|
|
</p>
|
|
<hr>
|
|
<h3>
|
|
<a name="Naming" id="Naming">Naming</a> conventions rationale
|
|
</h3>
|
|
<p>
|
|
The C++ standard committee's Library Working Group discussed this issue in
|
|
detail, and over a long period of time. The discussion was repeated again
|
|
in early boost postings. A short summary:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>Naming conventions are contentious, and although several are widely
|
|
used, no one style predominates.
|
|
</li>
|
|
<li>Given the intent to propose portions of boost for the next revision of
|
|
the C++ standard library, boost decided to follow the standard library's
|
|
conventions.
|
|
</li>
|
|
<li>Once a library settles on a particular convention, a vast majority of
|
|
stakeholders want that style to be consistently used.
|
|
</li>
|
|
</ul>
|
|
<hr>
|
|
<h3>
|
|
|
|
Source <a name="code_fonts" id="code_fonts">code fonts</a> rationale
|
|
</h3>
|
|
<p>
|
|
Dave Abrahams comments: An important purpose (I daresay the primary
|
|
purpose) of source code is communication: the documentation of intent. This
|
|
is a doubly important goal for boost, I think. Using a fixed-width font
|
|
allows us to communicate with more people, in more ways (diagrams are
|
|
possible) right there in the source. Code written for fixed-width fonts
|
|
using spaces will read reasonably well when viewed with a variable-width
|
|
font, and as far as I can tell every editor supporting variable-width fonts
|
|
also supports fixed width. I don't think the converse is true.
|
|
</p>
|
|
<hr>
|
|
<h3>
|
|
<a name="Tabs" id="Tabs">Tabs</a> rationale
|
|
</h3>
|
|
|
|
<p>
|
|
Tabs are banned because of the practical problems caused by tabs in
|
|
multi-developer projects like Boost, rather than any dislike in principle.
|
|
See <a href="mailing_lists.htm#archive">mailing list archives</a>. Problems
|
|
include maintenance of a single source file by programmers using tabs and
|
|
programmers using spaces, and the difficulty of enforcing a consistent tab
|
|
policy other than just "no tabs". Discussions concluded that Boost files
|
|
should either all use tabs, or all use spaces, and thus the decision to
|
|
stick with spaces.
|
|
</p>
|
|
<hr>
|
|
<h3>
|
|
ECMAScript/<a name="JavaScript" id="JavaScript">JavaScript</a> rationale
|
|
</h3>
|
|
|
|
<p>
|
|
Before the 1.29.0 release, two Boost libraries added ECMAScript/JavaScript
|
|
documentation. Controversy followed (see <a href=
|
|
"mailing_lists.htm#archive">mailing list archives</a>), and the developers
|
|
were asked to remove the ECMAScript/JavaScript. Reasons given for banning
|
|
included:
|
|
</p>
|
|
<ul>
|
|
<li>Incompatible with some older browsers and some text based browsers.
|
|
</li>
|
|
<li>Makes printing docs pages difficult.
|
|
</li>
|
|
<li>Often results in really bad user interface design.
|
|
</li>
|
|
|
|
<li>"It's just annoying in general."
|
|
</li>
|
|
<li>Would require Boost to test web pages for ECMAScript/JavaScript
|
|
compliance.
|
|
</li>
|
|
<li>Makes docs maintenance by other than the original developer more
|
|
difficult.
|
|
</li>
|
|
</ul>
|
|
<hr>
|
|
<h3>
|
|
<a name="Rationale_rationale" id="Rationale_rationale">Rationale
|
|
rationale</a>
|
|
|
|
</h3>
|
|
<p>
|
|
Rationale is defined as "The fundamental reasons for something; basis" by
|
|
the American Heritage Dictionary.
|
|
</p>
|
|
<p>
|
|
Beman Dawes comments: Failure to supply contemporaneous rationale for
|
|
design decisions is a major defect in many software projects. Lack of
|
|
accurate rationale causes issues to be revisited endlessly, causes
|
|
maintenance bugs when a maintainer changes something without realizing it
|
|
was done a certain way for some purpose, and shortens the useful lifetime
|
|
of software.
|
|
</p>
|
|
<p>
|
|
Rationale is fairly easy to provide at the time decisions are made, but
|
|
very hard to accurately recover even a short time later.
|
|
</p>
|
|
|
|
<hr>
|
|
<h3>
|
|
<a name="Acknowledgements" id="Acknowledgements">Acknowledgements</a>
|
|
rationale
|
|
</h3>
|
|
<p>
|
|
As a library matures, it almost always accumulates improvements suggested
|
|
to the authors by other boost members. It is a part of the culture of
|
|
boost.org to acknowledge such contributions, identifying the person making
|
|
the suggestion. Major contributions are usually acknowledged in the
|
|
documentation, while minor fixes are often mentioned in comments within the
|
|
code itself.
|
|
</p>
|
|
|
|
<hr>
|
|
<p>
|
|
Revised
|
|
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->
|
|
04 November, 2003<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
|
|
</p>
|
|
<p>
|
|
© <a name="Copyright" id="Copyright">Copyright</a> Beman Dawes 2003.
|
|
</p>
|
|
|
|
<p>
|
|
Distributed under the Boost Software License, Version 1.0. (See
|
|
accompanying file <a href="../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or copy
|
|
at <a href=
|
|
"http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)
|
|
</p>
|
|
</body>
|
|
</html>
|