x3/nonterminal/simple_trace.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2014 Joel de Guzman
0003     Copyright (c) 2001-2011 Hartmut Kaiser
0004
0005     Distributed under the Boost Software License, Version 1.0. (See accompanying
0006     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 ==============================================================================*/
0008 #if !defined(BOOST_SPIRIT_X3_SIMPLE_TRACE_DECEMBER_06_2008_1102AM)
0009 #define BOOST_SPIRIT_X3_SIMPLE_TRACE_DECEMBER_06_2008_1102AM
0010
0011 #include <boost/spirit/home/x3/support/unused.hpp>
0012 #include <boost/spirit/home/x3/support/traits/print_token.hpp>
0013 #include <boost/spirit/home/x3/support/traits/print_attribute.hpp>
0014 #include <boost/spirit/home/x3/nonterminal/debug_handler_state.hpp>
0015 #include <boost/type_traits/is_same.hpp>
0016 #include <iostream>
0017
0018 //  The stream to use for debug output
0019 #if !defined(BOOST_SPIRIT_X3_DEBUG_OUT)
0020 #define BOOST_SPIRIT_X3_DEBUG_OUT std::cerr
0021 #endif
0022
0023 //  number of tokens to print while debugging
0024 #if !defined(BOOST_SPIRIT_X3_DEBUG_PRINT_SOME)
0025 #define BOOST_SPIRIT_X3_DEBUG_PRINT_SOME 20
0026 #endif
0027
0028 //  number of spaces to indent
0029 #if !defined(BOOST_SPIRIT_X3_DEBUG_INDENT)
0030 #define BOOST_SPIRIT_X3_DEBUG_INDENT 2
0031 #endif
0032
0033 namespace boost { namespace spirit { namespace x3
0034 {
0035     namespace detail
0036     {
0037         template <typename Char>
0038         inline void token_printer(std::ostream& o, Char c)
0039         {
0040             // allow customization of the token printer routine
0041             x3::traits::print_token(o, c);
0042         }
0043     }
0044
0045     template <int IndentSpaces = 2, int CharsToPrint = 20>
0046     struct simple_trace
0047     {
0048         simple_trace(std::ostream& out)
0049           : out(out), indent(0) {}
0050
0051         void print_indent(int n) const
0052         {
0053             n *= IndentSpaces;
0054             for (int i = 0; i != n; ++i)
0055                 out << ' ';
0056         }
0057
0058         template <typename Iterator>
0059         void print_some(
0060             char const* tag
0061           , Iterator first, Iterator const& last) const
0062         {
0063             print_indent(indent);
0064             out << '<' << tag << '>';
0065             int const n = CharsToPrint;
0066             for (int i = 0; first != last && i != n && *first; ++i, ++first)
0067                 detail::token_printer(out, *first);
0068             out << "</" << tag << '>' << std::endl;
0069
0070             // $$$ FIXME convert invalid xml characters (e.g. '<') to valid
0071             // character entities. $$$
0072         }
0073
0074         template <typename Iterator, typename Attribute, typename State>
0075         void operator()(
0076             Iterator const& first
0077           , Iterator const& last
0078           , Attribute const& attr
0079           , State state
0080           , std::string const& rule_name) const
0081         {
0082             switch (state)
0083             {
0084                 case pre_parse:
0085                     print_indent(indent++);
0086                     out
0087                         << '<' << rule_name << '>'
0088                         << std::endl;
0089                     print_some("try", first, last);
0090                     break;
0091
0092                 case successful_parse:
0093                     print_some("success", first, last);
0094                     if (!is_same<Attribute, unused_type>::value)
0095                     {
0096                         print_indent(indent);
0097                         out
0098                             << "<attributes>";
0099                         traits::print_attribute(out, attr);
0100                         out
0101                             << "</attributes>";
0102                         out << std::endl;
0103                     }
0104                     print_indent(--indent);
0105                     out
0106                         << "</" << rule_name << '>'
0107                         << std::endl;
0108                     break;
0109
0110                 case failed_parse:
0111                     print_indent(indent);
0112                     out << "<fail/>" << std::endl;
0113                     print_indent(--indent);
0114                     out
0115                         << "</" << rule_name << '>'
0116                         << std::endl;
0117                     break;
0118             }
0119         }
0120
0121         std::ostream& out;
0122         mutable int indent;
0123     };
0124
0125     namespace detail
0126     {
0127         typedef simple_trace<
0128             BOOST_SPIRIT_X3_DEBUG_INDENT, BOOST_SPIRIT_X3_DEBUG_PRINT_SOME>
0129         simple_trace_type;
0130
0131         inline simple_trace_type&
0132         get_simple_trace()
0133         {
0134             static simple_trace_type tracer(BOOST_SPIRIT_X3_DEBUG_OUT);
0135             return tracer;
0136         }
0137     }
0138 }}}
0139
0140 #endif