add benchmark

benchmark_test.go

@@ -0,0 +1,79 @@
+package kong
+
+import (
+	"fmt"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func BenchmarkKong_interpolate(b *testing.B) {
+	prepareKong := func(t testing.TB, count int) *Kong {
+		t.Helper()
+		k := &Kong{
+			vars:     make(Vars, count),
+			registry: NewRegistry().RegisterDefaults(),
+		}
+		for i := 0; i < count; i++ {
+			helpVar := fmt.Sprintf("help_param%d", i)
+			k.vars[helpVar] = strconv.Itoa(i)
+		}
+		grammar := &struct {
+			Param0 string `help:"${help_param0}"`
+		}{}
+		model, err := build(k, grammar)
+		require.NoError(t, err)
+		for i := 0; i < count; i++ {
+			model.Node.Flags = append(model.Node.Flags, &Flag{
+				Value: &Value{
+					Help: fmt.Sprintf("${help_param%d}", i),
+					Tag:  newEmptyTag(),
+				},
+			})
+		}
+		k.Model = model
+		return k
+	}
+
+	for _, count := range []int{5, 500, 5000} {
+		count := count
+		b.Run(strconv.Itoa(count), func(b *testing.B) {
+			var err error
+			k := prepareKong(b, count)
+			for i := 0; i < b.N; i++ {
+				err = k.interpolate(k.Model.Node)
+			}
+			require.NoError(b, err)
+			b.ReportAllocs()
+		})
+	}
+}
+
+func Benchmark_interpolateValue(b *testing.B) {
+	varsLen := 10000
+	k := &Kong{
+		vars:     make(Vars, 10000),
+		registry: NewRegistry().RegisterDefaults(),
+	}
+	for i := 0; i < varsLen; i++ {
+		helpVar := fmt.Sprintf("help_param%d", i)
+		k.vars[helpVar] = strconv.Itoa(i)
+	}
+	grammar := struct {
+		Param9999 string `kong:"cmd,help=${help_param9999}"`
+	}{}
+	model, err := build(k, &grammar)
+	if err != nil {
+		b.FailNow()
+	}
+	k.Model = model
+	flag := k.Model.Flags[0]
+	for i := 0; i < b.N; i++ {
+		err = k.interpolateValue(flag.Value, k.vars)
+		if err != nil {
+			b.FailNow()
+		}
+	}
+	b.ReportAllocs()
+}