♻️ Refactor Incremental Generator to single function with options

gen_int.go

@@ -0,0 +1,55 @@
+package nomino
+
+import (
+	"fmt"
+	"strconv"
+)
+
+type incConf struct {
+	start int
+	step  int
+	cb    func(int) string
+}
+
+// IncrementalOption sets an option for the Incremental Generator
+type IncrementalOption func(c *incConf)
+
+// Incremental generates a name that is a series of integers.
+// By default it begins at 0 and increments by 1 each time.
+func Incremental(opts ...IncrementalOption) Generator {
+	c := incConf{step: 1, cb: strconv.Itoa}
+	for _, opt := range opts {
+		opt(&c)
+	}
+
+	next := c.start
+	return func(*Config) (string, error) {
+		out := c.cb(next)
+		next += c.step
+		return out, nil
+	}
+}
+
+// IncrementalStart sets the starting integer for Incremental
+func IncrementalStart(start int) IncrementalOption {
+	return func(c *incConf) {
+		c.start = start
+	}
+}
+
+// IncrementalStepsets the step by which Incremental increases with each invocation.
+func IncrementalStep(step int) IncrementalOption {
+	return func(c *incConf) {
+		c.step = step
+	}
+}
+
+// IncrementalFormatsets the format for the number generated by Incremental.
+// It will be formatted with Printf. This is mostly likely useful with a format like "%02d"
+func IncrementalFormat(format string) IncrementalOption {
+	return func(c *incConf) {
+		c.cb = func(i int) string {
+			return fmt.Sprintf(format, i)
+		}
+	}
+}