Spirit Parser Framework - Example

Example

#include #include #include #include using namespace std; using namespace BOOST_SPIRIT_CLASSIC_NS; int main { string input; cout << "Input a line." << endl; getline(cin, input); cout << "Got '" << input << "'." << endl; unsigned count = 0; /* Next line parses the input (input.c_str), using a parser constructed with the following semantics (indentation matches source for clarity): Zero or more occurrences of ( literal string "cat" ( when matched, increment the counter "count" ) or any character (to move on finding the next occurrence of "cat") ) */ parse(input.c_str, *( str_p("cat") | anychar_p )); /* The parser is constructed by the compiler using operator overloading and template matching, so the actual work is done within spirit::parse, and the expression starting with * only initializes the rule object that the parse function uses. */ // last, show results. cout << "The input had " << count << " occurrences of 'cat'" << endl; return 0; }

Of course, there are better algorithms suited for string searching, but this example gives an idea how to construct rules and attach actions to them.

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