ceph/src/boost/libs/spirit/classic/doc/organization.html

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  13     <td width="85%"> <font size="6" face="Verdana, Arial, Helvetica, sans-serif"><b>Organization</b></font>
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  27 <p>The framework is highly modular and is organized in layers:</p>
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  30     <td><div align="center">
  31         <table width="40%" border="1" cellpadding="3" cellspacing="3" class="table_cells">
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  33             <td><div align="center"><font color="#003366"><strong>iterator</strong></font></div></td>
  34             <td><div align="center"><font color="#003366"><strong>actor</strong></font></div></td>
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  37         <font color="#003366" size="3"><br>
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  40   <tr>
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  44             <td><div align="center"><font color="#003366"><strong>debug</strong></font></div></td>
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  47         <font color="#003366" size="3"><br>
  48         </font></div></td>
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  54             <td><div align="center"><font color="#003366"><strong>attribute</strong></font></div></td>
  55             <td><div align="center"><font color="#003366"><strong>dynamic</strong></font></div></td>
  56             <td><div align="center"><font color="#003366"><strong>error_handling</strong></font></div></td>
  57             <td><div align="center"><font color="#003366"><strong>symbols</strong></font></div></td>
  58             <td><div align="center"><font color="#003366"><strong>tree</strong></font></div></td>
  59             <td><div align="center"><font color="#003366"><strong>utility</strong></font></div></td>
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  67         <table width="20%" border="1" cellpadding="3" cellspacing="3" class="table_cells">
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  69             <td><div align="center"><font color="#003366"><strong>meta</strong></font></div></td>
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  72         <font color="#003366"><br>
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  79             <td colspan="4"><div align="center"><font color="#003366"><strong><font size="4">core</font></strong></font></div></td>
  80           </tr>
  81           <tr>
  82             <td><div align="center"><font color="#003366"><strong>scanner</strong></font></div></td>
  83             <td><div align="center"><font color="#003366"><strong>primitives</strong></font></div></td>
  84             <td><div align="center"><font color="#003366"><strong>composite</strong></font></div></td>
  85             <td><div align="center"><font color="#003366"><strong>non_terminal</strong></font></div></td>
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  91 <p>Spirit has four layers, plus an independent top layer. The independent layer,
  92   comprising of actor and iterator, does not rely on the other layers. The framework's
  93   architecture is completely orthogonal. The relationship among the layers is
  94   acyclic. Lower layers do not depend nor know the existence of upper layers.
  95   Modules in a layer do not depend on other modules in the same layer. </p>
  96 <p>The client may use only the modules that she wants without incurring any compile
  97   time nor run time penalty. A minimalistic approach is to use only the core as
  98   is. The highly streamlined core is usable by itself. The core is sufficiently
  99   suitable for tasks such as micro parsing.</p>
 100 <p>The <strong>iterator</strong> module is independent of Spirit and may be used
 101   in other non-Spirit applications. This module is a compilation of stand-alone
 102   iterators and iterator wrappers compatible with Spirit.
 103
 104
 105  Over time, these iterators have been found to be most useful for parsing with Spirit. </p>
 106 <p>The <strong>actor</strong> module, also independent of Spirit, is a compilation
 107   of predefined semantic actions that covers the most common semantics processing
 108   tasks.</p>
 109 <p>The <strong>debug</strong> module provides library wide parser debugging. This
 110   module hooks itself up transparently into the core non-intrusively and only
 111   when necessary.</p>
 112 <p>The<strong> attribute</strong> module introduces advanced semantic action machinery
 113   with emphasis on extraction and passing of data up and down the parser hierarchy
 114   through inherited and synthesized attributes. Attributes may also be used to
 115   actually control the parsing. Parametric parsers are a form of dynamic parsers
 116   that changes their behavior at run time based on some attribute or data.</p>
 117 <p>The <strong>dynamic</strong> module focuses on parsers with behavior that can
 118   be modified at run-time.</p>
 119 <p><strong>error_handling</strong>. The framework would not be complete without
 120   Error Handling. C++'s exception handling mechanism is a perfect match for Spirit
 121   due to its highly recursive functional nature. C++ Exceptions are used extensively
 122   by this module for handling errors.</p>
 123 <p>The<strong> symbols</strong> module focuses on symbol table management. This module
 124   is rather basic now. The goal is to build a sub-framework that will be able
 125   to accommodate C++ style multiple scope mechanisms. C++ is a great model for
 126   the complexity of scoping that perhaps has no parallel in any other language.
 127   There are classes and inheritance, private, protected and public access restrictions,
 128   friends, namespaces, using declarations, using directives, Koenig lookup (Argument
 129   Dependent Lookup) and more. The symbol table functionality we have now will
 130   be the basis of a complete facility that will attempt to model this.</p>
 131 <blockquote>
 132   <p><em><font color="#003366">I wish that I could ever see, a structure as lovely
 133     as a tree</font></em><font color="#003366">...</font></p>
 134 </blockquote>
 135 <p> Parse Tree and Abstract Syntax Tree (AST) generation are handled by the <b>Tree</b>
 136   module. There are advantages with Parse Trees and Abstract Syntax Trees over
 137   semantic actions. You can make multiple passes over the data without having
 138   to re-parse the input. You can perform transformations on the tree. You can
 139   evaluate things in any order you want, whereas with attribute schemes you have
 140   to process in a begin to end fashion. You do not have to worry about backtracking
 141   and action side effects that may occur with an ambiguous grammar.</p>
 142 <p>The <b>utility</b> module is a set of commonly useful parsers and support classes
 143   that were found to be useful in handling common tasks such as list processing,
 144   comments, confix expressions, etc.</p>
 145 <p><strong>meta</strong>, provides metaprogramming facilities for advanced Spirit
 146   developers. This module facilitates compile-time and run-time introspection
 147   of Spirit parsers.</p>
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 158 <p class="copyright">Copyright &copy; 1998-2003 Joel de Guzman<br>
 159   <br>
 160   <font size="2">Use, modification and distribution is subject to the Boost Software
 161     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
 162     http://www.boost.org/LICENSE_1_0.txt)</font></p>
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