markov.go: slightly reworked

modules/markov.go

@@ -130,13 +130,9 @@ func (p MarkovPrefix) String() string {
 
 // Shift removes the first word from the Prefix and appends the given word.
 func (p MarkovPrefix) Shift(word string) {
-	if len(p) < *markovPrefixLen {
-		p = append(p, word)
-	} else {
 	copy(p, p[1:])
 	p[len(p)-1] = word
 }
-}
 
 // MarkovChain contains a map ("chain") of prefixes to a list of suffixes.
 // A prefix is a string of prefixLen words joined with spaces.
@@ -155,6 +151,15 @@ func markovNewChain(prefixLen int) *MarkovChain {
 	}
 }
 
+func markovContains(a []string, s string) bool {
+	for _, v := range a {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}
+
 // Write parses the bytes into prefixes and suffixes that are stored in MarkovChain.
 func (c *MarkovChain) Write(in string) (int, error) {
 	in = strings.ToLower(in)
@@ -164,17 +169,20 @@ func (c *MarkovChain) Write(in string) (int, error) {
 	}
 	sr := strings.NewReader(in)
 	p := make(MarkovPrefix, c.prefixLen)
+	c.mu.Lock()
+	defer c.mu.Unlock()
 	for {
 		var s string
 		if _, err := fmt.Fscan(sr, &s); err != nil {
 			break
 		}
 		key := p.String()
-		c.mu.Lock()
+		if !markovContains(c.MarkovChain[key], s) {
 			c.MarkovChain[key] = append(c.MarkovChain[key], s)
-		c.mu.Unlock()
 			xlog.Debug("Chain len: %d, learned [%s] [%s]", len(c.MarkovChain), key, s)
-		fmt.Println(c.MarkovChain[key])
+		} else {
+			xlog.Debug("Chain len: %d, [%s] [%s] is already known", len(c.MarkovChain), key, s)
+		}
 		p.Shift(s)
 	}
 	return len(in), nil
@@ -193,19 +201,10 @@ func (c *MarkovChain) Generate(n int, in string) string {
 	var words []string
 	var start string
 	for attempt := 0; attempt < 10; attempt++ {
-		/*
 		p = make(MarkovPrefix, c.prefixLen)
-			p = strings.Split(in, " ")
-			if len(p) > c.prefixLen {
-				i := rand.Intn(len(p) - 2)
-				p = p[i : i+c.prefixLen]
-			}
-		*/
-		p = make(MarkovPrefix, 1)
 		inWords := strings.Split(in, " ")
 		start = inWords[rand.Intn(len(inWords))]
-		p[0] = start
-		//ss = p.String()
+		p.Shift(start)
 		xlog.Debug("Looking for answer on [%s]", start)
 		for i := 0; i < n; i++ {
 			choices := c.MarkovChain[p.String()]