v0.1.0 — Optional types for Go

First Release

opt — Go-idiomatic Option<T> with full SQL + JSON integration.

Highlights

• Generic Value[T] — foundation on sql.Null[T] (Go 1.24+)
• 9 concrete types — String, Int, Int32, Int16, Float, Bool, Byte, Time
• Field[T] — three-state (absent/null/value) for PATCH API — unique in Go ecosystem
• Functional API — Map, FlatMap, Equal
• zero/ subpackage — alternative semantics (zero value = null)
• Zero-allocation unmarshal, Bool marshal <1ns
• encoding/json/v2 compatible
• Stdlib only — zero external dependencies

Install

go get github.com/coregx/opt@v0.1.0

Quick Start

name := opt.StringFrom("Alice")
age := opt.NewInt(0, false) // null

fmt.Println(name.Or("unknown")) // "Alice"
fmt.Println(age.OrZero())       // 0

data, _ := json.Marshal(struct {
    Name opt.String `json:"name"`
    Age  opt.Int    `json:"age"`
}{name, age})
// {"name":"Alice","age":null}

Full documentation: README | pkg.go.dev