pike code

#!/usr/bin/env pike

class string2id {
        // map from string to identifier
        mapping(string:int) string2id;

        // a number of assigned IDs
        int counter;

        // constructor
        void create()
        {
                string2id = ([]); // initialise string2id to empty mapping
                counter = 0;
        }

        // our main function
        int get_id (string str)
        {
                if (string2id[str] != 0)
                        return string2id[str];

                ++counter;
                string2id[str] = counter;
                return counter;
        }
};

string2id mapper;

void get_id_and_print (string feature)
{
        int id = mapper.get_id(feature);
        write("Feature %s has an identifier %d\n", feature, id);
}

int main (array(string) args)
{
        // creating an object of class string2id
        mapper = string2id();

        // bag of words
        get_id_and_print("apple");
        get_id_and_print("table");
        get_id_and_print("map");
        get_id_and_print("picture");
        get_id_and_print("table");
        get_id_and_print("man");
        get_id_and_print("apple");

        // very special features
        get_id_and_print("providefor_between_company1_and_company2");

        return 0;
}