randx: add Init method that ensures a Rand source is present

base/randx/rand.go

@@ -12,6 +12,11 @@ import "math/rand"
 // rand.Rand methods, to support the use of either the
 // global rand generator or a separate Rand source.
 type Rand interface {
+	// Init initializes this random source with given seed, ensuring
+	// that there is a Rand object in place if not already, and
+	// then calling Seed with given value.
+	Init(seed int64)
+
 	// Seed uses the provided seed value to initialize the generator to a deterministic state.
 	// Seed should not be called concurrently with any other Rand method.
 	Seed(seed int64)
@@ -102,6 +107,28 @@ func NewSysRand(seed int64) *SysRand {
 	return r
 }
 
+// InitSysRand initializes the given pointer to a [randx.Rand]
+// source to a new SysRand if it is nil, and otherwise calls
+// Init on the existing one, all with given initial seed.
+func InitSysRand(r *Rand, seed int64) {
+	if *r == nil {
+		*r = NewSysRand(seed)
+	} else {
+		(*r).Init(seed)
+	}
+}
+
+// Init initializes this random source with given seed, ensuring
+// that there is a Rand object in place if not already, and
+// then calling Seed with given value.
+func (r *SysRand) Init(seed int64) {
+	if r.Rand == nil {
+		r.NewRand(seed)
+		return
+	}
+	r.Rand.Seed(seed)
+}
+
 // NewRand sets Rand to a new rand.Rand source using given seed.
 func (r *SysRand) NewRand(seed int64) {
 	r.Rand = rand.New(rand.NewSource(seed))

go.mod

@@ -8,16 +8,16 @@ go 1.25.6
 // https://github.com/googleapis/go-genproto/issues/1015
 
 require (
-	cogentcore.org/core v0.3.21
+	cogentcore.org/core v0.3.22
 	github.com/cogentcore/readline v0.1.3
 	github.com/cogentcore/yaegi v0.0.0-20260116172027-700fbf8949f3
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/nsf/termbox-go v1.1.1
 	github.com/stretchr/testify v1.11.1
 	golang.org/x/exp v0.0.0-20260112195511-716be5621a96
-	golang.org/x/tools v0.41.0
+	golang.org/x/tools v0.42.0
 	gonum.org/v1/gonum v0.17.0
-	google.golang.org/grpc v1.78.0
+	google.golang.org/grpc v1.79.3
 	google.golang.org/protobuf v1.36.11
 )
 
@@ -60,15 +60,15 @@ require (
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/rogpeppe/go-internal v1.13.1 // indirect
 	github.com/tdewolff/parse/v2 v2.8.5 // indirect
-	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/crypto v0.49.0 // indirect
 	golang.org/x/image v0.35.0 // indirect
-	golang.org/x/mod v0.32.0 // indirect
-	golang.org/x/net v0.49.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/sys v0.40.0 // indirect
-	golang.org/x/text v0.33.0 // indirect
-	google.golang.org/genproto v0.0.0-20260226221140-a57be14db171 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20260217215200-42d3e9bedb6d // indirect
+	golang.org/x/mod v0.33.0 // indirect
+	golang.org/x/net v0.52.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
+	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
+	google.golang.org/genproto v0.0.0-20260401024825-9d38bb4040a9 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260401001100-f93e5f3e9f0f // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	modernc.org/knuth v0.5.4 // indirect
 	modernc.org/token v1.1.0 // indirect