1 files changed, 52 insertions, 0 deletions
diff --git a/roll.go b/roll.go
new file mode 100644
index 0000000..1848754
--- /dev/null
+++ b/roll.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"os"
+	"regexp"
+	"strconv"
+	"time"
+)
+
+func usage() {
+	fmt.Printf("Arguments are in the format [<COUNT>]d<SIZE>[+MOD]\n")
+}
+
+func roll(input string) {
+	parser := regexp.MustCompile("^([0-9]*)d([0-9]+)([+-][0-9]+)?$")
+	parts := parser.FindStringSubmatch(input)
+	if len(parts) < 2 {
+		usage()
+		return
+	}
+	dice, _ := strconv.Atoi(parts[1])
+	die_size, _ := strconv.Atoi(parts[2])
+	mod := 0
+	if len(parts) > 3 {
+		mod, _ = strconv.Atoi(parts[3])
+	}
+	if dice < 1 {
+		dice = 1
+	}
+
+	total := 0
+	for i := 0; i < dice; i++ {
+		v := rand.Intn(die_size) + 1
+		fmt.Printf("%d+", v)
+		total += v
+	}
+	total += mod
+	fmt.Printf("%d = %d\n", mod, total)
+}
+
+func main() {
+	rand.Seed(time.Now().UTC().UnixNano())
+	if len(os.Args) == 1 {
+		usage()
+	}
+	args := os.Args[1:]
+	for _, arg := range args {
+		roll(arg)
+	}
+}