function totalIt(sofar,next){ return sofar+next;}  //used to sum up all the elements of an array (see reduce())
mister.score = function(code,attempt,range){ //score needs to use mister.counts so I put it here.
    let cCode = mister.counts(code,range);
    let cAttempt = mister.counts(attempt,range);
    let total = cCode.map((x,i)=> Math.min(x,cAttempt[i])).reduce(totalIt); // # unordered matches...uses colour counts
    let exact = code.map((x,i)=> x==attempt[i]?1:0).reduce(totalIt);   // # exact matches
    return [exact,total-exact];
}
mister.filter = function(list,fact,range){
    return list.filter(x => mister.score(x,fact.code,range).map((s,i)=>Math.abs(s-fact.score[i])).reduce(totalIt) ==0)
}
mister.makePuzzle = function(size,range,guess=[],max=2){ // create a puzzle (the facts) for "size" holes with "range" number of colours
    // this is fragile code in that has a bunch of assumptions about the args....
    // by having a few good guesses preloaded helps to not have boring facts first
    let answerA = mister.rand(size,range);  //set one answer that will end up part of the solution space
    let list = mister.codeSet(size,range);
    let facts =[];
    let cur = 0;
    while (list.length > max) { // the solution space needs to be reduced by adding more facts
        if (cur >= guess.length) guess.push([]);  // add a blank guess to be filled
        if (guess[cur].length == 0)
            guess[cur] = mister.rand(size,range); // get a new guess 
        let newFact = {"code":guess[cur],"score":mister.score(answerA, guess[cur],range)}; // other solutions must get the same scoring as answerA
        let revised = mister.filter(list, newFact ,range); // compute possible solutions with this new fact 
        if (revised.length < list.length) {
            list = revised;
            facts.push(newFact);
            cur++;
        } else {
            guess[cur] = []; //didn't work...the new fact didn't reduce the solution space
        }
    }
    return {"facts":facts,"solns":list,"choices":Array.from({length:range},(_,i)=> i)};
}