Adds a function to find all categories

compiler/book.go

@@ -18,6 +18,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"fmt"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/alecthomas/template"
@@ -58,6 +59,7 @@ var bookTempl = `
 func MakeBook(path string, opts *settings.Settings) {
 	// Everything needs to be compiled
 	CompileDir(path, opts)
+	fmt.Println(scoreCategories(&scores))
 	// Compile the book template
 	var templ = template.Must(template.New("songBook").Parse(bookTempl))
 
@@ -97,3 +99,19 @@ func MakeBook(path string, opts *settings.Settings) {
 	err = os.Remove(texPath)
 	helpers.Check(err, "could not remove songbook latex template")
 }
+
+// scoreCategories returns a slice of all categories used
+// in the given slice of scores
+func scoreCategories(scores *[]settings.Score) []string {
+	catMap := make(map[string]struct{})
+	for i := range *scores {
+		for _, cat := range (*scores)[i].Categories {
+			catMap[cat] = struct{}{}
+		}
+	}
+	categories := make([]string, 0, len(catMap))
+	for cat := range catMap {
+		categories = append(categories, cat)
+	}
+	return categories
+}