refined: initial sketch for type Struct

2 files changed, 66 insertions, 0 deletions

diff --git a/refined/struct.go b/refined/struct.go
new file mode 100644
index 0000000..35a0c85
--- /dev/null
+++ b/refined/struct.go
@@ -0,0 +1,12 @@
+// SPDX-FileCopyrightText: 2025 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package refined
+
+type Struct[P any] struct {
+	Has P
+}
+
+func NewStruct[P any](payload P) Struct[P] {
+	return Struct[P]{Has: payload}
+}
diff --git a/refined/struct_test.go b/refined/struct_test.go
new file mode 100644
index 0000000..b07b8a5
--- /dev/null
+++ b/refined/struct_test.go
@@ -0,0 +1,54 @@
+// SPDX-FileCopyrightText: 2025 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package refined_test
+
+import (
+	"fmt"
+	"math"
+	"regexp"
+	"testing"
+
+	. "github.com/majewsky/gg/internal/test"
+	"github.com/majewsky/gg/refined"
+)
+
+type AccountID struct {
+	refined.Scalar[AccountID, uint64]
+}
+
+func (AccountID) Refine(c refined.Challenge[AccountID, uint64]) (AccountID, error) {
+	s, err := refined.RangeCheck(c, 1, math.MaxUint64)
+	return AccountID{s}, err
+}
+
+type AccountName struct {
+	refined.Scalar[AccountName, string]
+}
+
+var accountNameRx = regexp.MustCompile(`^[a-z][a-z0-9_]*$`)
+
+func (AccountName) Refine(c refined.Challenge[AccountName, string]) (AccountName, error) {
+	s, err := refined.RegexpCheck(c, accountNameRx)
+	return AccountName{s}, err
+}
+
+type AccountInfo = refined.Struct[AccountInfoPayload]
+
+type AccountInfoPayload struct {
+	ID   AccountID   `json:"id,omitzero"`
+	Name AccountName `json:"name,omitzero"`
+}
+
+func (p AccountInfoPayload) ReadableName() string {
+	return fmt.Sprintf("%s (ID %d)", p.Name.Raw(), p.ID.Raw())
+}
+
+func TestAccountInfo(t *testing.T) {
+	var info AccountInfo //nolint:staticcheck
+	info = refined.NewStruct(AccountInfoPayload{
+		ID: refined.Literal[AccountID](53),
+	})
+	info.Has.Name = refined.Literal[AccountName]("hello")
+	AssertEqual(t, info.Has.ReadableName(), "hello (ID 53)")
+}