Begin dependency injection

diego.go

@@ -0,0 +1,43 @@
+package diego
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type Router struct {
+	mux http.ServeMux
+}
+
+type InjectionContext struct{}
+
+type InjectionFunction[T any] func(InjectionContext) T
+
+type InjectionToken[T any] struct {
+	Name          string
+	InjectionFunc InjectionFunction[T]
+}
+
+var injectionTokens map[string]any = make(map[string]any)
+
+func Inject[T any](token InjectionToken[T]) T {
+	var value = injectionTokens[token.Name]
+
+	if value == nil {
+		value = token.InjectionFunc(InjectionContext{})
+		injectionTokens[token.Name] = value
+	}
+
+	var injection, ok = value.(T)
+
+	if !ok {
+		panic(fmt.Sprintf("FATAL ERROR: Tried to inject a value with the wrong type, expected = %T, got = %T", *new(T), value))
+	}
+	return injection
+
+}
+
+func Test() {}
+
+func (r *Router) Start() {
+}

diego_test.go

@@ -0,0 +1,22 @@
+package diego
+
+import "testing"
+
+const testString = "hello"
+
+func GetBasicString(ctx InjectionContext) string {
+	return testString
+}
+
+var BasicStringToken InjectionToken[string] = InjectionToken[string]{
+	"BASIC_STRING",
+	GetBasicString,
+}
+
+func TestDependencyInjection(t *testing.T) {
+	value := Inject(BasicStringToken)
+
+	if value != testString {
+		t.Errorf("Could not inject basic string token, expected = %s(%T), got = %s(%T)", testString, testString, value, value)
+	}
+}

go.mod

@@ -0,0 +1,3 @@
+module robaertschi.xyz/diego
+
+go 1.23.2