Add initial functions

README.md

@@ -1,2 +1,2 @@
 # cli-validation
-Library to help with flag validation of urfave/cli
+Library to help with flag validation of urfave/cli(current for v3 only). This ensures that urfave/cli codebase remains compact and clean of optional features

go.mod

@@ -0,0 +1,11 @@
+module github.com/urfave/cli-validation
+
+go 1.19
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

validation.go

@@ -0,0 +1,87 @@
+package validation
+
+import (
+	"fmt"
+)
+
+type Signed interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64
+}
+
+type Unsigned interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
+}
+
+type Integer interface {
+	Signed | Unsigned
+}
+
+type Float interface {
+	~float32 | ~float64
+}
+
+type Ordered interface {
+	Integer | Float
+}
+
+// ConditionOrError ir a helper function to make writing
+// validation functions much easier
+func ConditionOrError(cond bool, err error) error {
+	if cond {
+		return nil
+	}
+	return err
+}
+
+// ValidationChainAll allows one to chain a sequence of validation
+// functions to construct a single validation function. All the
+// individual validations must pass for the validation to succeed
+func ValidationChainAll[T any](fns ...func(T) error) func(T) error {
+	return func(v T) error {
+		for _, fn := range fns {
+			if err := fn(v); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+}
+
+// ValidationChainAny allows one to chain a sequence of validation
+// functions to construct a single validation function. Atleast one
+// of the individual validations must pass for the validation to succeed
+func ValidationChainAny[T any](fns ...func(T) error) func(T) error {
+	return func(v T) error {
+		var errs []error
+		for _, fn := range fns {
+			if err := fn(v); err == nil {
+				return nil
+			} else {
+				errs = append(errs, err)
+			}
+		}
+		return fmt.Errorf("%+v", errs)
+	}
+}
+
+// Min means that the value to be checked needs to be atleast(and including)
+// the checked value
+func Min[T Ordered](c T) func(T) error {
+	return func(v T) error {
+		return ConditionOrError(v >= c, fmt.Errorf("%v is not less than %v", v, c))
+	}
+}
+
+// Max means that the value to be checked needs to be atmost(and including)
+// the checked value
+func Max[T Ordered](c T) func(T) error {
+	return func(v T) error {
+		return ConditionOrError(v <= c, fmt.Errorf("%v is not greater than %v", v, c))
+	}
+}
+
+// Max means that the value to be checked needs to be atmost(and including)
+// the checked value
+func RangeInclusive[T Ordered](a, b T) func(T) error {
+	return ValidationChainAll[T](Min[T](a), Max[T](b))
+}

validation_test.go

@@ -0,0 +1,167 @@
+package validation
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type testcase[T any] struct {
+	name        string
+	f           func(T) error
+	input       T
+	errExpected bool
+}
+
+func testWithInput[T any](t *testing.T, tcases []testcase[T]) {
+	r := require.New(t)
+	for _, tc := range tcases {
+		t.Run(tc.name, func(t *testing.T) {
+			err := tc.f(tc.input)
+			if tc.errExpected {
+				r.Error(err)
+			} else {
+				r.NoError(err)
+			}
+		})
+	}
+}
+
+func TestMin(t *testing.T) {
+
+	inputs := []testcase[int]{
+		{
+			name:  "min lower limit",
+			f:     Min[int](10),
+			input: 10,
+		},
+		{
+			name:  "min normal",
+			f:     Min[int](10),
+			input: 11,
+		},
+		{
+			name:        "min failure",
+			f:           Min[int](10),
+			input:       8,
+			errExpected: true,
+		},
+	}
+
+	testWithInput[int](t, inputs)
+}
+
+func TestMax(t *testing.T) {
+
+	inputs := []testcase[float64]{
+		{
+			name:  "max upper limit",
+			f:     Max[float64](10.0),
+			input: 10.0,
+		},
+		{
+			name:  "max normal",
+			f:     Max[float64](10.0),
+			input: 9.0,
+		},
+		{
+			name:        "max failure",
+			f:           Max[float64](10.0),
+			input:       10.00001,
+			errExpected: true,
+		},
+	}
+
+	testWithInput[float64](t, inputs)
+}
+
+func TestRange(t *testing.T) {
+
+	inputs := []testcase[uint64]{
+		{
+			name:  "lower limit",
+			f:     RangeInclusive[uint64](10, 16),
+			input: 10,
+		},
+		{
+			name:  "upper limit",
+			f:     RangeInclusive[uint64](10, 16),
+			input: 16,
+		},
+		{
+			name:        "lower limit failure",
+			f:           RangeInclusive[uint64](10, 16),
+			input:       9,
+			errExpected: true,
+		},
+		{
+			name:        "upper limit failure",
+			f:           RangeInclusive[uint64](10, 16),
+			input:       17,
+			errExpected: true,
+		},
+		{
+			name:  "normal",
+			f:     RangeInclusive[uint64](10, 16),
+			input: 12,
+		},
+	}
+
+	testWithInput[uint64](t, inputs)
+}
+
+func TestDisjointRange(t *testing.T) {
+
+	inputs := []testcase[int16]{
+		{
+			name:  "lower limit lower range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 10,
+		},
+		{
+			name:  "upper limit lower range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 16,
+		},
+		{
+			name:  "lower limit upper range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 56,
+		},
+		{
+			name:  "upper limit upper range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 67,
+		},
+		{
+			name:  "normal lower range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 13,
+		},
+		{
+			name:  "normal upper range",
+			f:     ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input: 60,
+		},
+		{
+			name:        "failure below lower range",
+			f:           ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input:       1,
+			errExpected: true,
+		},
+		{
+			name:        "failure in between lower and upper range",
+			f:           ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input:       20,
+			errExpected: true,
+		},
+		{
+			name:        "failure above upper range",
+			f:           ValidationChainAny[int16](RangeInclusive[int16](10, 16), RangeInclusive[int16](56, 67)),
+			input:       70,
+			errExpected: true,
+		},
+	}
+
+	testWithInput[int16](t, inputs)
+}