✨ Add Incremental* Generators

generators.go

@@ -2,6 +2,7 @@ package nomino
 
 import (
 	"errors"
+	"strconv"
 	"time"
 
 	"github.com/google/uuid"
@@ -85,7 +86,7 @@ func FormattedTime(t time.Time, f string) Generator {
 	}
 }
 
-// FileTimestamp is the default format for WithTimestampUTC and WithTimeUTC
+// FileTimestampNoTZ is the default format for WithTimestampUTC and WithTimeUTC
 const FileTimestampNoTZ string = "2006-01-02_03-05-06"
 
 // TimestampUTC generates a date and time for the current time in UTC without a timezone in the format.
@@ -97,3 +98,28 @@ func TimestampUTC() Generator {
 func TimeUTC(t time.Time) Generator {
 	return FormattedTime(t.UTC(), FileTimestampNoTZ)
 }
+
+// Incremental generates a name that is a series of integers starting at 0
+func Incremental() Generator {
+	return IncrementalWithStartAndStep(0, 1)
+}
+
+// IncrementalWithStart generates a name that is a series of integers starting at the specified number
+func IncrementalWithStart(start int) Generator {
+	return IncrementalWithStartAndStep(start, 1)
+}
+
+// IncrementalWithStep generates a name that is a series of integers, starting at 0, and increasing the specified number each time
+func IncrementalWithStep(step int) Generator {
+	return IncrementalWithStartAndStep(0, step)
+}
+
+// InrementalWithStartAndStep generates a name that is a series of integers, starting at the specified number, and increasing the specified step each time
+func IncrementalWithStartAndStep(start, step int) Generator {
+	next := start
+	return func() (string, error) {
+		out := strconv.Itoa(next)
+		next += step
+		return out, nil
+	}
+}

generators_examples_test.go

@@ -18,3 +18,75 @@ func ExampleWithGenerator_custom_generator() {
 	// hello.txt
 	// hello
 }
+
+func ExampleIncremental() {
+	conf := NewConfig(WithPrefix("foo"), WithGenerator(Incremental()))
+
+	str, _ := Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	// Output:
+	// foo_0.txt
+	// foo_1.txt
+	// foo_2.txt
+}
+
+func ExampleIncrementalWithStart() {
+	conf := NewConfig(WithPrefix("foo"), WithGenerator(IncrementalWithStart(42)))
+
+	str, _ := Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	// Output:
+	// foo_42.txt
+	// foo_43.txt
+	// foo_44.txt
+}
+
+func ExampleIncrementalWithStep() {
+	conf := NewConfig(WithPrefix("foo"), WithGenerator(IncrementalWithStep(2)))
+
+	str, _ := Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	// Output:
+	// foo_0.txt
+	// foo_2.txt
+	// foo_4.txt
+}
+
+func ExampleIncrementalWithStartAndStep() {
+	conf := NewConfig(WithPrefix("foo"), WithGenerator(IncrementalWithStartAndStep(42, 2)))
+
+	str, _ := Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	str, _ = Make(conf)
+	fmt.Println(str)
+
+	// Output:
+	// foo_42.txt
+	// foo_44.txt
+	// foo_46.txt
+}