The set of tokens of the language is {ITEM,,,[,]} (mind the second token, which is a comma), where the token ITEM represents any non-empty sequence of alphanumeric characters and underscore. We want to parse the language of lists of items. The list must be delimited by brackets, and the items separated by commas, with an optional comma at the end of the list. Examples of correct expressions are “[eggs_many, ham, SPAM]”, “[bread, 2sausages, potato1,]”, “[bacon]”, “[,]”, “[]” and examples of incorrect expressions are “[butter,,jam]”, “[,scone]”. The generated AST must have the token [ as root, with the items as children. For instance, the input [honey,tea,] produces the following AST [(honey,tea)