gistfile1.js

var seq = seq || (function () {
    
    // Private vars
    var sequences = {},
        def_seq   = 'unnamed',
        instance;    
    
    // Methods implementation
    return {
        curVal: function(seq_name) {
                    seq_name = seq_name || def_seq;
                    if (typeof sequences[seq_name] === 'undefined') {
                        this.reset(seq_name);
                    }
                    return 'L_'+sequences[seq_name];
                  },

        nextVal: function(seq_name) {
                     seq_name = seq_name || def_seq;
                     if (typeof sequences[seq_name] === 'undefined') {
                         this.reset(seq_name);
                     }
                      return 'L_' + (sequences[seq_name] += 1);
                  },

        reset: function(seq_name) {
                    seq_name = seq_name || def_seq;
                    sequences[seq_name] = 0;
                }
    };

}());