String 列表序言中列表解释器的字符串卡在2项上

我编写了一种名为List Prolog的编程语言（在这种语言中，谓词以

[n，predicate\u name]

开头，变量是

[v，variable\u name]

），但在获取一些代码时遇到了困难（一种带有definite子句语法的算法，它获取一个字符串并将其转换为Prolog术语，或者列表，等等）使用n，而不是每个列表（在字符串中）2个项目的查询

另外，List Prolog与Prolog不同，因为它包含的语法要求用户编写自己的基本情况，类似于用C编写的解释器，即

          [[n,compound213],["","",[v,t],[v,t]]],

          [[n,compound213],[[v,u],[v,u],[v,t],[v,t]]],

在查询中，

[[n，grammar1]，“[[\'aa\'，b]，1]，[v，t]]]

起作用，即只有两个项目，即可以转换为字符串的一部分的

[\'aa\'，b]

，但不能超过这个数字，即

[\'aa\'，b，\'c\'，[]

，因此

[[n，grammar1]，“[[\'aa\'，b，'c\'，[]v]/code>不起作用

注意：该算法旨在获取一个字符串，如
“[\“a\”，b，3]”
，并返回一个术语，即
[“a”，b，3]
，其中包含字符串、原子、数字、空列表和更多这些元素的列表

% The query:

test(15,[[n,grammar1],["[[\"aa\",b,\"c\",[]],1]",[v,t]]],

% The code:

[
          [[n,grammar1],[[v,u],[v,t]],":-",
          [
                     [[n,compound],[[v,u],"",[],[v,t]]]
          ]
          ],

          [[n,compound213],["","",[v,t],[v,t]]],

          [[n,compound213],[[v,u],[v,u],[v,t],[v,t]]],

          [[n,compound],[[v,t],[v,u]],"->",
          ["[","]",
          [[n,compound213],[[v,t],[v,u]]]]],

          [[n,compound],[[v,t],[v,u]],"->",
          ["[",[[n,compound21],[[v,t],[v,v]]],"]",
          [[n,compound213],[[v,v],[v,u]]]]],

          [[n,compound212],["","",[v,t],[v,t]]],

          [[n,compound212],[[v,u],[v,u],[v,t],[v,t]]],

          [[n,compound21],[[v,t],[v,u]],"->",
          [[[n,item],[[v,i]]],
          % [[n,lookahead],["]"]],
          [[n,code],[[n,wrap],[[v,i],[v,itemname1]]],
          [[n,append],[[v,t],[v,itemname1],[v,v]]]],
          [[n,compound212],[[v,v],[v,u]]]]],

          [[n,compound21],[[v,t],[v,u]],"->",
          [[[n,item],[[v,i]]],",",
          
          %[[n,code],[[n,trace]]],
          
          [[n,compound21],[[],[v,compound1name]]],
          [[n,code],[[n,wrap],[[v,i],[v,itemname1]]],
          [[n,append],[[v,t],[v,itemname1],[v,v]]],
          [[n,append],[[v,v],[v,compound1name],[v,u]]]]]],

          [[n,item],[[v,t]],"->",["\"",[[n,word21],["",[v,t]]],
            "\""]],

          [[n,item],[[v,t]],"->",
          [[[n,number21],["",[v,u]]],[[n,code],
          [[n,stringtonumber],[[v,u],[v,t]]]]]],

          [[n,item],[[v,t]],"->",[[[n,word21_atom],["",[v,t1]]],
          [[n,code],[[n,atom_string],[[v,t],[v,t1]]]]]], % atoms

          [[n,item],[[v,t]],"->",[[[n,compound],[[],[v,t]]]]],

          [[n,number212],["","",[v,t],[v,t]]],

          [[n,number212],[[v,u],[v,u],[v,t],[v,t]]],

          [[n,number21],[[v,t],[v,u]],"->",
          [[v,a],[[n,commaorrightbracketnext]],
          [[n,code],[[n,stringtonumber],[[v,a],[v,a1]]],
          [[n,number],[[v,a1]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,number212],[[v,v],[v,u]]]]],

          [[n,number21],[[v,t],[v,u]],"->",
          [[v,a],
          [[n,code],[[n,stringtonumber],[[v,a],[v,a1]]],
          [[n,number],[[v,a1]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,number21],["",[v,numberstring]]],
          [[n,code],[[n,stringconcat],
          [[v,v],[v,numberstring],[v,u]]]]]],

          [[n,word212],["","",[v,t],[v,t]]],

          [[n,word212],[[v,u],[v,u],[v,t],[v,t]]],

          [[n,word21],[[v,t],[v,u]],"->",
          [[v,a],[[n,quote_next]],
          [[n,code],
          [[n,not],[[[n,=],[[v,a],"\""]]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,word212],[[v,v],[v,u]]]]],

          [[n,word21],[[v,t],[v,u]],"->",
          [[v,a],
          [[n,code],
          [[n,not],[[[n,=],[[v,a],"\""]]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,word21],["",[v,wordstring]]],
          [[n,code],
          [[n,stringconcat],[[v,v],[v,wordstring],[v,u]]]]]],


          [[n,word212_atom],["","",[v,t],[v,t]]],

          [[n,word212_atom],[[v,u],[v,u],[v,t],[v,t]]],

          [[n,word21_atom],[[v,t],[v,u]],"->",
          [[v,a],[[n,commaorrightbracketnext]],
          [[n,code],
          [[n,not],[[[n,=],[[v,a],"\""]]]],
          [[n,not],[[[n,=],[[v,a],"["]]]],
          [[n,not],[[[n,=],[[v,a],"]"]]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,word212_atom],[[v,v],[v,u]]]]],

          [[n,word21_atom],[[v,t],[v,u]],"->",
          [[v,a],
          [[n,code],
          [[n,not],[[[n,=],[[v,a],"\""]]]],
          [[n,not],[[[n,=],[[v,a],"["]]]],
          [[n,not],[[[n,=],[[v,a],"]"]]]],
          [[n,stringconcat],[[v,t],[v,a],[v,v]]]],
          [[n,word21_atom],["",[v,wordstring]]],
          [[n,code],
          [[n,stringconcat],[[v,v],[v,wordstring],[v,u]]]]]],
          
          [[n,commaorrightbracketnext],"->",
          [[[n,lookahead],[","]]]],

          [[n,commaorrightbracketnext],"->",
          [[[n,lookahead],["]"]]]],
          
          [[n,quote_next],"->",
          [[[n,lookahead],["\""]]]],

          
          [[n,lookahead],[[v,a],[v,a],[v,b]],":-",
          [[[n,stringconcat],[[v,b],[v,d],[v,a]]]]]
],

% The desired result:

[[[[v,t],[["aa",b,"c",[]],1]]]]).

我通过取消对行的注释修复了代码：

[[n,lookahead],["]"]],

在取消注释该行以打开调试之后

[[n,code],[[n,trace]]],

这表明在没有lookahead语句检查下一个字符是否为“]”的情况下，代码错误地在2个以上项目之后跟随它所在的子句，失败了，而使用lookahead语句，它所在的子句只在n个项目列表的末尾成功了