rationalized context convertion to dict and string types

operator-context.go

@@ -40,7 +40,7 @@ func evalContextValue(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error
 	}
 
 	if sourceCtx != nil {
-		v = contextToDict(sourceCtx)
+		v = sourceCtx.ToDict()
 	} else if childValue != nil {
 		it, ok := childValue.(kern.Iterator)
 		if !ok {
@@ -63,28 +63,6 @@ func evalContextValue(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error
 	return
 }
 
-func contextToDict(ctx kern.ExprContext) (dict *kern.DictType) {
-	// Variables
-	keys := ctx.EnumVars(nil)
-	vars := kern.MakeDict()
-	for _, key := range keys {
-		value, _ := ctx.GetVar(key)
-		vars.SetItem(key, value)
-	}
-	// Functions
-	keys = ctx.EnumFuncs(func(name string) bool { return true })
-	funcs := kern.MakeDict()
-	for _, key := range keys {
-		funcInfo, _ := ctx.GetFuncInfo(key)
-		funcs.SetItem(key, funcInfo)
-	}
-
-	dict = kern.MakeDict()
-	dict.SetItem("vars", vars)
-	dict.SetItem("funcs", funcs)
-	return
-}
-
 // init
 func init() {
 	scan.RegisterTermConstructor(scan.SymDoubleDollar, newContextTerm)