Added list '[]' data type. Fix: function with no arguments

operand-list.go

@@ -0,0 +1,35 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operand-list.go
+package expr
+
+// -------- list term
+func newListTerm(args []*term) *term {
+	return &term{
+		tk:       *NewToken(SymList, "[]"),
+		class:    classVar,
+		kind:     kindUnknown,
+		parent:   nil,
+		children: args,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalList,
+	}
+}
+
+// -------- list func
+func evalList(ctx exprContext, self *term) (v any, err error) {
+	items := make([]any, len(self.children))
+	for i, tree := range self.children {
+		var param any
+		if param, err = tree.compute(ctx); err != nil {
+			break
+		}
+		items[i] = param
+	}
+	if err == nil {
+		v = items
+	}
+	return
+}