result_type operator() (argument_type line)
{
if( !m_parsing )
{
std::string::size_type start = line.find("$(IF ", 0);
std::string::size_type end = line.find(')', start);
std::string symbol = line.substr(start + 5, end - start - 5);
// if the symbol exists in the map, parse normally until we hit $(END)
// if it doesn't exist, skip until we hit $(END)
m_output = symbols.find(symbol) != symbols.end();
m_parsing = true;
}
else
{
// look for $(END)
if( line.find("$(END)") != std::string::npos )
{
// stop parsing
m_parsing = false;
parsers.erase(parsers.end()-1);
return true;
}
symbol_parser::m_should_output = m_output;
return false;
}
return true;
}
result_type operator() (argument_type line)
{
// parse for our symbols
for( std::string::size_type pos = 0; (pos = line.find('$', pos)) != std::string::npos; pos++ )
{
std::string::size_type end = line.find(')', pos);
std::string::iterator it_begin = line.begin() + pos;
std::string::iterator it_end = line.begin() + end;
std::string statement = line.substr(pos + 2, end - pos - 2);
// check for commands
std::string::size_type space_pos;
if( (space_pos = statement.find_first_of(" )", 0)) != std::string::npos )
{
// space must come first
if( statement[space_pos] == ' ' )
{
// push the parser for this command
std::string command = statement.substr(0, space_pos);
parsers.push_back(parser_factory(command, symbols, parsers, input, output));
parsers.back()->operator()(line);
return true;
}
}
symbol_map::const_iterator sym = symbols.find(statement);
if( sym == symbols.end() )
throw std::runtime_error(std::string("Unknown symbol encountered: ") + statement);
line.replace(pos, end - pos + 1, sym->second);
pos++;
}
if( m_should_output )
output << line << "\n";
return true;
}
