New counter flag type

```
-vvv
```

Will give a value of 3

```
-v=4 -v
```

Will give a value of 5

1 files changed, 84 insertions, 0 deletions

diff --git a/count.go b/count.go
new file mode 100644
index 0000000..d061368
--- /dev/null
+++ b/count.go
@@ -0,0 +1,84 @@
+package pflag
+
+import (
+	"fmt"
+	"strconv"
+)
+
+// -- count Value
+type countValue int
+
+func newCountValue(val int, p *int) *countValue {
+	*p = val
+	return (*countValue)(p)
+}
+
+func (i *countValue) Set(s string) error {
+	v, err := strconv.ParseInt(s, 0, 64)
+	// -1 means that no specific value was passed, so increment
+	if v == -1 {
+		*i = countValue(*i + 1)
+	} else {
+		*i = countValue(v)
+	}
+	return err
+}
+
+func (i *countValue) Type() string {
+	return "count"
+}
+
+func (i *countValue) String() string { return fmt.Sprintf("%v", *i) }
+
+func countConv(sval string) (interface{}, error) {
+	i, err := strconv.Atoi(sval)
+	if err != nil {
+		return nil, err
+	}
+	return i, nil
+}
+
+func (f *FlagSet) GetCount(name string) (int, error) {
+	val, err := f.getFlagType(name, "count", countConv)
+	if err != nil {
+		return 0, err
+	}
+	return val.(int), nil
+}
+
+func (f *FlagSet) CountVar(p *int, name string, usage string) {
+	f.CountVarP(p, name, "", usage)
+}
+
+func (f *FlagSet) CountVarP(p *int, name, shorthand string, usage string) {
+	flag := f.VarPF(newCountValue(0, p), name, shorthand, usage)
+	flag.NoOptDefVal = "-1"
+}
+
+func CountVar(p *int, name string, usage string) {
+	CommandLine.CountVar(p, name, usage)
+}
+
+func CountVarP(p *int, name, shorthand string, usage string) {
+	CommandLine.CountVarP(p, name, shorthand, usage)
+}
+
+func (f *FlagSet) Count(name string, usage string) *int {
+	p := new(int)
+	f.CountVarP(p, name, "", usage)
+	return p
+}
+
+func (f *FlagSet) CountP(name, shorthand string, usage string) *int {
+	p := new(int)
+	f.CountVarP(p, name, shorthand, usage)
+	return p
+}
+
+func Count(name string, usage string) *int {
+	return CommandLine.CountP(name, "", usage)
+}
+
+func CountP(name, shorthand string, usage string) *int {
+	return CommandLine.CountP(name, shorthand, usage)
+}