Control vars are now stored in the globalCtx only.

However, it is still allowed to store control var in a local context in special situation

global-context.go

@@ -4,7 +4,10 @@
 // global-context.go
 package expr
 
-import "path/filepath"
+import (
+	"path/filepath"
+	"strings"
+)
 
 var globalCtx *SimpleStore
 
@@ -63,7 +66,70 @@ func GetFuncInfo(ctx ExprContext, name string) (item ExprFunc, exists bool, owne
 	return
 }
 
+func GlobalCtrlSet(name string, newValue any) (currentValue any) {
+	if !strings.HasPrefix(name, "_") {
+		name = "_" + name
+	}
+	currentValue, _ = globalCtx.GetVar(name)
+
+	globalCtx.SetVar(name, newValue)
+	return currentValue
+}
+
+func GlobalCtrlGet(name string) (currentValue any) {
+	if !strings.HasPrefix(name, "_") {
+		name = "_" + name
+	}
+	currentValue, _ = globalCtx.GetVar(name)
+	return currentValue
+}
+
+func CtrlEnable(ctx ExprContext, name string) (currentStatus bool) {
+	if !strings.HasPrefix(name, "_") {
+		name = "_" + name
+	}
+	if v, exists := ctx.GetVar(name); exists && IsBool(v) {
+		currentStatus, _ = v.(bool)
+	}
+
+	ctx.SetVar(name, true)
+	return currentStatus
+}
+
+func CtrlDisable(ctx ExprContext, name string) (currentStatus bool) {
+	if !strings.HasPrefix(name, "_") {
+		name = "_" + name
+	}
+	if v, exists := ctx.GetVar(name); exists && IsBool(v) {
+		currentStatus, _ = v.(bool)
+	}
+
+	ctx.SetVar(name, false)
+	return currentStatus
+}
+
+func CtrlIsEnabled(ctx ExprContext, name string) (status bool) {
+	var v any
+	var exists bool
+
+	if !strings.HasPrefix(name, "_") {
+		name = "_" + name
+	}
+
+	if v, exists = ctx.GetVar(name); !exists {
+		v, exists = globalCtx.GetVar(name)
+	}
+
+	if exists {
+		if b, ok := v.(bool); ok {
+			status = b
+		}
+	}
+	return
+}
+
 func init() {
 	globalCtx = NewSimpleStore()
+	initDefaultVars(globalCtx)
 	ImportBuiltinsFuncs(globalCtx)
 }