adding cs235

cs235/lab07/fungulator/main.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math/rand"
+	"os"
+	"strings"
+	"time"
+)
+
+type LengthError struct {
+	Count int
+}
+
+func (e LengthError) Error() string {
+	return fmt.Sprintf("%d is not long enough (must be longer than 2)", e.Count)
+}
+
+func parse(words []string) (map[string][]string, string, error) {
+	if len(words) < 3 {
+		return nil, "", LengthError{len(words)}
+	}
+	mapping := make(map[string][]string)
+	var a, b, k, v, first_prefix string
+	for i := 0; i < len(words)-2; i++ {
+		a = words[i]
+		b = words[i+1]
+		k = fmt.Sprintf("%v %v", a, b)
+		if i == 0 {
+			first_prefix = k
+		}
+		v = words[i+2]
+		mapping[k] = append(mapping[k], v)
+	}
+	k = fmt.Sprintf("%v %v", words[len(words)-2], words[len(words)-1])
+	v = "THE_END"
+	mapping[k] = append(mapping[k], v)
+	return mapping, first_prefix, nil
+}
+
+func generateText(mapping map[string][]string, first_prefix string) string {
+	cur_prefix := first_prefix
+	output := first_prefix
+	for {
+		suffix := mapping[cur_prefix][rand.Intn(len(mapping[cur_prefix]))]
+		if suffix == "THE_END" {
+			break
+		}
+		output += fmt.Sprintf(" %v", suffix)
+		_prefix := strings.SplitN(cur_prefix, " ", 2)
+        cur_prefix = fmt.Sprintf("%v %v", _prefix[1], suffix)
+	}
+	return output
+}
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+	instream := bufio.NewReader(os.Stdin)
+	for s, err := instream.ReadBytes('\n'); err == nil; s, err = instream.ReadBytes('\n') {
+		words := strings.Fields(string(s))
+		mapping, first_prefix, err := parse(words)
+		var generated_text string
+		if err != nil {
+			generated_text = err.Error()
+		} else {
+			generated_text = generateText(mapping, first_prefix)
+		}
+		fmt.Printf("%v\n\t%v\n\t%v\n", words, mapping, generated_text)
+	}
+}