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Initial commit of quickbook conversion of docs.
[SVN r37942]
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John Maddock
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doc/regex_replace.qbk
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doc/regex_replace.qbk
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[section:regex_replace regex_replace]
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#include <boost/regex.hpp>
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The algorithm [regex_replace] searches through a string finding all the
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matches to the regular expression: for each match it then calls
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[match_results_format] to format the string and sends the result to the
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output iterator. Sections of text that do not match are copied to the
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output unchanged only if the /flags/ parameter does not have the
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flag `format_no_copy` set. If the flag `format_first_only` is set then
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only the first occurrence is replaced rather than all occurrences.
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template <class OutputIterator, class BidirectionalIterator, class traits, class charT>
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OutputIterator regex_replace(OutputIterator out,
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BidirectionalIterator first,
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BidirectionalIterator last,
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const basic_regex<charT, traits>& e,
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const basic_string<charT>& fmt,
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match_flag_type flags = match_default);
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template <class traits, class charT>
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basic_string<charT> regex_replace(const basic_string<charT>& s,
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const basic_regex<charT, traits>& e,
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const basic_string<charT>& fmt,
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match_flag_type flags = match_default);
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[h4 Description]
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template <class OutputIterator, class BidirectionalIterator, class traits, class charT>
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OutputIterator regex_replace(OutputIterator out,
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BidirectionalIterator first,
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BidirectionalIterator last,
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const basic_regex<charT, traits>& e,
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const basic_string<charT>& fmt,
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match_flag_type flags = match_default);
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Enumerates all the occurences of expression /e/ in the sequence \[first, last),
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replacing each occurence with the string that results by merging the
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match found with the format string /fmt/, and copies the resulting string to /out/.
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If the flag `format_no_copy` is set in /flags/ then unmatched sections of
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text are not copied to output.
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If the flag `format_first_only` is set in flags then only the first
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occurence of /e/ is replaced.
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The manner in which the format string /fmt/ is interpretted, along with the
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rules used for finding matches, are determined by the flags set in /flags/:
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see [match_flag_type].
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[*Effects]: Constructs an [regex_iterator] object:
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regex_iterator<BidirectionalIterator, charT, traits, Allocator>
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i(first, last, e, flags),
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and uses /i/ to enumerate through all of the matches /m/ of type
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[match_results] `<BidirectionalIterator>` that occur within the sequence
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\[first, last).
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If no such matches are found and
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!(flags & format_no_copy)
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then calls
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std::copy(first, last, out).
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Otherwise, for each match found, if
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!(flags & format_no_copy)
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calls
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std::copy(m.prefix().first, m.prefix().last, out),
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and then calls
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m.format(out, fmt, flags).
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Finally if
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!(flags & format_no_copy)
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calls
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std::copy(last_m.suffix().first, last_m,suffix().last, out)
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where /last_m/ is a copy of the last match found.
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If `flags & format_first_only` is non-zero then only the first match found
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is replaced.
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[*Throws]: `std::runtime_error` if the complexity of matching the expression
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against an N character string begins to exceed O(N[super 2]), or if the
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program runs out of stack space while matching the expression (if Boost.Regex is
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configured in recursive mode), or if the matcher exhausts it's permitted
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memory allocation (if Boost.Regex is configured in non-recursive mode).
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[*Returns]: out.
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template <class traits, class charT>
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basic_string<charT> regex_replace(const basic_string<charT>& s,
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const basic_regex<charT, traits>& e,
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const basic_string<charT>& fmt,
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match_flag_type flags = match_default);
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[*Effects]: Constructs an object `basic_string<charT> result`, calls
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`regex_replace(back_inserter(result), s.begin(), s.end(), e, fmt, flags)`,
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and then returns `result`.
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[h4 Examples]
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The following example takes C/C++ source code as input, and outputs
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syntax highlighted HTML code.
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#include <fstream>
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#include <sstream>
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#include <string>
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#include <iterator>
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#include <boost/regex.hpp>
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#include <fstream>
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#include <iostream>
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// purpose:
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// takes the contents of a file and transform to
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// syntax highlighted code in html format
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boost::regex e1, e2;
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extern const char* expression_text;
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extern const char* format_string;
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extern const char* pre_expression;
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extern const char* pre_format;
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extern const char* header_text;
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extern const char* footer_text;
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void load_file(std::string& s, std::istream& is)
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{
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s.erase();
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s.reserve(is.rdbuf()->in_avail());
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char c;
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while(is.get(c))
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{
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if(s.capacity() == s.size())
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s.reserve(s.capacity() * 3);
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s.append(1, c);
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}
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}
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int main(int argc, const char** argv)
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{
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try{
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e1.assign(expression_text);
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e2.assign(pre_expression);
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for(int i = 1; i < argc; ++i)
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{
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std::cout << "Processing file " << argv[i] << std::endl;
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std::ifstream fs(argv[i]);
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std::string in;
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load_file(in, fs);
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std::string out_name(std::string(argv[i]) + std::string(".htm"));
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std::ofstream os(out_name.c_str());
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os << header_text;
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// strip '<' and '>' first by outputting to a
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// temporary string stream
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std::ostringstream t(std::ios::out | std::ios::binary);
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std::ostream_iterator<char, char> oi(t);
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boost::regex_replace(oi, in.begin(), in.end(),
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e2, pre_format, boost::match_default | boost::format_all);
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// then output to final output stream
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// adding syntax highlighting:
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std::string s(t.str());
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std::ostream_iterator<char, char> out(os);
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boost::regex_replace(out, s.begin(), s.end(),
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e1, format_string, boost::match_default | boost::format_all);
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os << footer_text;
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}
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}
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catch(...)
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{ return -1; }
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return 0;
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}
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extern const char* pre_expression = "(<)|(>)|(&)|\\r";
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extern const char* pre_format = "(?1<)(?2>)(?3&)";
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const char* expression_text =
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// preprocessor directives: index 1
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"(^[[:blank:]]*#(?:[^\\\\\\n]|\\\\[^\\n[:punct:][:word:]]*[\\n[:punct:][:word:]])*)|"
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// comment: index 2
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"(//[^\\n]*|/\\*.*?\\*/)|"
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// literals: index 3
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"\\<([+-]?(?:(?:0x[[:xdigit:]]+)|(?:(?:[[:digit:]]*\\.)?[[:digit:]]+"
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"(?:[eE][+-]?[[:digit:]]+)?))u?(?:(?:int(?:8|16|32|64))|L)?)\\>|"
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// string literals: index 4
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"('(?:[^\\\\']|\\\\.)*'|\"(?:[^\\\\\"]|\\\\.)*\")|"
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// keywords: index 5
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"\\<(__asm|__cdecl|__declspec|__export|__far16|__fastcall|__fortran|__import"
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"|__pascal|__rtti|__stdcall|_asm|_cdecl|__except|_export|_far16|_fastcall"
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"|__finally|_fortran|_import|_pascal|_stdcall|__thread|__try|asm|auto|bool"
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"|break|case|catch|cdecl|char|class|const|const_cast|continue|default|delete"
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"|do|double|dynamic_cast|else|enum|explicit|extern|false|float|for|friend|goto"
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"|if|inline|int|long|mutable|namespace|new|operator|pascal|private|protected"
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"|public|register|reinterpret_cast|return|short|signed|sizeof|static|static_cast"
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"|struct|switch|template|this|throw|true|try|typedef|typeid|typename|union|unsigned"
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"|using|virtual|void|volatile|wchar_t|while)\\>"
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;
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const char* format_string = "(?1<font color=\"#008040\">$&</font>)"
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"(?2<I><font color=\"#000080\">$&</font></I>)"
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"(?3<font color=\"#0000A0\">$&</font>)"
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"(?4<font color=\"#0000FF\">$&</font>)"
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"(?5<B>$&</B>)";
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const char* header_text =
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"<HTML>\n<HEAD>\n"
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"<TITLE>Auto-generated html formated source</TITLE>\n"
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"<META HTTP-EQUIV=\"Content-Type\" CONTENT=\"text/html; charset=windows-1252\">\n"
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"</HEAD>\n"
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"<BODY LINK=\"#0000ff\" VLINK=\"#800080\" BGCOLOR=\"#ffffff\">\n"
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"<P> </P>\n<PRE>";
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const char* footer_text = "</PRE>\n</BODY>\n\n";
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[endsect]
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