1<html> 2<head> 3<title>Style Guide</title> 4<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> 5<link rel="stylesheet" href="theme/style.css" type="text/css"> 6</head> 7 8<body> 9<table width="100%" border="0" background="theme/bkd2.gif" cellspacing="2"> 10 <tr> 11 <td width="10"> 12 </td> 13 <td width="85%"> <font size="6" face="Verdana, Arial, Helvetica, sans-serif"><b>Style 14 Guide </b></font></td> 15 <td width="112"><a href="http://spirit.sf.net"><img src="theme/spirit.gif" width="112" height="48" align="right" border="0"></a></td> 16 </tr> 17</table> 18<br> 19<table border="0"> 20 <tr> 21 <td width="10"></td> 22 <td width="30"><a href="../index.html"><img src="theme/u_arr.gif" border="0"></a></td> 23 <td width="30"><a href="portability.html"><img src="theme/l_arr.gif" border="0"></a></td> 24 <td width="30"><a href="techniques.html"><img src="theme/r_arr.gif" border="0"></a></td> 25 </tr> 26</table> 27<p> At some point, especially when there are lots of semantic actions attached 28 to various points, the grammar tends to be quite difficult to follow. In order 29 to keep an easy-to-read, consistent en aesthetically pleasing look to the Spirit 30 code, the following coding styleguide is advised. </p> 31<p>This coding style is adapted and extended from the ANTLR/PCCTS style (Terrence 32 Parr) and <a href="http://groups.yahoo.com/group/boost/files/coding_guidelines.html">Boost 33 coding guidelines</a> (David Abrahams and Nathan Myers) and is the combined 34 work of Joel de Guzman, Chris Uzdavinis and Hartmut Kaiser.</p> 35<ul> 36 <li> Rule names use std C++ (Boost) convention. The rule name may be very long.</li> 37 <li>The '=' is neatly indented 4 spaces below. Like Boost, use spaces instead 38 of tabs. </li> 39 <li>Breaking the operands into separate lines puts the semantic actions neatly 40 to the right. </li> 41 <li>Semicolon at the last line terminates the rule. </li> 42 <li>The adjacent parts of a sequence should be indented accordingly to have 43 all, what belongs to one level, at one indentation level.</li> 44</ul> 45<pre><span class=identifier> program 46 </span><span class=special>= </span><span class=identifier>program_heading </span><span class=special>[</span><span class=identifier>heading_action</span><span class=special>] 47 </span><span class=identifier> </span><span class=special> >> </span><span class=identifier>block </span><span class=special>[</span><span class=identifier>block_action</span><span class=special>] 48 </span><span class=identifier> </span><span class=special> >> </span><span class=literal>'.' 49 </span><span class=identifier> </span><span class=special>| </span><span class=identifier>another_sequence 50 </span><span class=special>>> </span><span class=identifier>etc 51 </span><span class=identifier> </span><span class=special>;</span></pre> 52<ul> 53 <li>Prefer literals in the grammar instead of identifiers. e.g. <tt>"program"</tt> 54 instead of <tt>PROGRAM</tt>, <tt>'>='</tt> instead of <tt>GTE</tt> and 55 <tt>'.' </tt>instead of <tt>DOT</tt>. This makes it much easier to read. If 56 this isn't possible (for instance where the used tokens must be identified 57 through integers) capitalized identifiers should be used instead. </li> 58 <li> Breaking the operands may not be needed for short expressions. e.g. <tt>*(',' 59 >> file_identifier)</tt> as long as the line does not exceed 80 characters. 60 </li> 61 <li> If a sequence fits on one line, put spaces inside the parentheses to clearly 62 separate them from the rules. </li> 63</ul> 64<pre> <span class=identifier>program_heading 65 </span><span class=special>= </span><span class=identifier>as_lower_d</span><span class=special>[</span><span class=string>"program"</span><span class=special>] 66 >> </span><span class=identifier>identifier 67 </span><span class=special>>> </span><span class=literal>'(' 68 </span><span class=special>>> </span><span class=identifier>file_identifier 69 </span><span class=special>>> *( </span><span class=literal>',' </span><span class=special>>> </span><span class=identifier>file_identifier </span><span class=special>) 70 >> </span><span class=literal>')' 71 </span><span class=special>>> </span><span class=literal>';' 72 </span><span class=special>;</span></pre> 73<ul> 74 <li> Nesting directives: If a rule does not fit on one line (80 characters) 75 it should be continued on the next line intended by one level. </li> 76 <li>The brackets of directives, semantic expressions (using Phoenix or LL lambda 77 expressions) or parsers should be placed as follows. </li> 78</ul> 79<pre> <span class=identifier>identifier 80 </span><span class=special>= </span><span class=identifier>nocase 81 </span><span class=special>[ 82 </span><span class=identifier>lexeme 83 </span><span class=special>[ 84 </span><span class=identifier>alpha </span><span class=special>>> *(</span><span class=identifier>alnum </span><span class=special>| </span><span class=literal>'_'</span><span class=special>) [</span><span class=identifier>id_action</span><span class=special>] 85 ] 86 ] 87 ;</span></pre> 88<ul> 89 <li> Nesting unary operators (e.g.Kleene star) </li> 90 <li>Unary rule operators (Kleene star, <tt>'!'</tt>, <tt>'+'</tt> etc.) should 91 be moved out one space before the corresponding indentation level, if this 92 rule has a body or a sequence after it, which does not fit on on line. This 93 makes the formatting more consistent and moves the rule 'body' at the same 94 indentation level as the rule itself, highlighting the unary operator.</li> 95</ul> 96<pre><span class=special> </span><span class=identifier>block 97 </span><span class=special>= *( </span><span class=identifier>label_declaration_part 98 </span><span class=special>| </span><span class=identifier>constant_definition_part 99 </span><span class=special>| </span><span class=identifier>type_definition_part 100 </span><span class=special>| </span><span class=identifier>variable_declaration_part 101 </span><span class=special>| </span><span class=identifier>procedure_and_function_declaration_part 102 </span><span class=special>) 103 >> </span><span class=identifier>statement_part 104 </span><span class=special>;</span></pre> 105<table border="0"> 106 <tr> 107 <td width="10"></td> 108 <td width="30"><a href="../index.html"><img src="theme/u_arr.gif" border="0"></a></td> 109 <td width="30"><a href="portability.html"><img src="theme/l_arr.gif" border="0"></a></td> 110 <td width="30"><a href="techniques.html"><img src="theme/r_arr.gif" border="0"></a></td> 111 </tr> 112</table> 113<br> 114<hr size="1"> 115<p class="copyright">Copyright © 2001-2003 Joel de Guzman<br> 116 Copyright © 2001-2002 Hartmut Kaiser<br> 117 Copyright © 2001-2002 Chris Uzdavinis<br> 118 <br> 119 <font size="2">Use, modification and distribution is subject to the Boost Software 120 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 121 http://www.boost.org/LICENSE_1_0.txt)</font></p> 122<p class="copyright"> </p> 123</body> 124</html> 125
