move filter stuff into separate source file

filter.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"github.com/jbrukh/bayesian"
+)
+
+const (
+	// good is the class of good mails that are not supposed to be Spam
+	good bayesian.Class = "Good"
+	// junk is the class of Spam mails
+	junk bayesian.Class = "Junk"
+)
+
+// Classifiers contains the classifiers for mail subjects and bodies
+type Classifiers struct {
+	Subject, Body *bayesian.Classifier
+}

main.go

@@ -5,15 +5,6 @@ import (
 	"fmt"
 	"log"
 	"os"
-
-	"github.com/jbrukh/bayesian"
-)
-
-const (
-	// good is the class of good mails that are not supposed to be Spam
-	good bayesian.Class = "Good"
-	// junk is the class of Spam mails
-	junk bayesian.Class = "Junk"
 )
 
 var (
@@ -21,11 +12,6 @@ var (
 	Processed map[string]bool
 )
 
-// Classifiers contains the classifiers for mail subjects and bodies
-type Classifiers struct {
-	Subject, Body *bayesian.Classifier
-}
-
 func main() {
 	// Get the Maildir to be handled
 	wd, err := os.Getwd()