关于 nlp:Pereira 中的 Prolog 运算符错误

Prolog operator errors in Pereira

在 Ubuntu Linux 中使用 SWI Prolog 7.7.2,我正在尝试运行 "talk"
Pereira 和 Schieber 的模块(附录 A,
http://www.mtome.com/Publications/PNLA/prolog-digital.pdf)。

复制后,粘贴到文本编辑器(Sublime),并调整
换行符(主要)匹配原始的、运行的 swipl,然后
[\\'talk.P\\'],我遇到了超过两打"语法错误:运算符
预期" 错误,例如(目录位置被 [...] 替换):

Lines 15-20:

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main_loop :-
    write(>>),       % prompt the user
    read_sent(Words),   % read a sentence
    talk(Words, Reply), % process it with TALK
    print_reply(Reply), % generate a printed reply
    main_loop.          % process more sentences

ERROR: [...]/talk.P:16:15: Syntax error: Operator expected

---Line 38:

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talk(_Sentence, error(’too difficult’)).

ERROR: [...]/talk.P:38:25: Syntax error: Operator expected

---Lines 76-77:

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% Replying to some other type of sentence.
reply(_Type, _FreeVars, _Clause, error(’unknown type’)).

ERROR: [...]/talk.P:77:42: Syntax error: Operator expected

---Lines 87-91:

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print_reply(error(ErrorType)) :-
    write(’Error:"’), write(ErrorType), write(."’), nl.

print_reply(asserted(Assertion)) :-
    write(’Asserted"’), write(Assertion), write(."’), nl.

ERROR: [...]/talk.P:91:12: Syntax error: Operator expected

---注意我也遇到十个单例变量警告,但不确定这是否会成为问题,例如:

---Lines 59-60:

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reply(query, FreeVars,
    (answer(Answer):-Condition), Reply) :- Warning: [...]/talk.P:59:  Singleton variables:

[FreeVars,Condition,FreeVars?Condition] Warning: [...]/talk.P:59:
Singleton variable in branch: FreeVars?Condition

---Lines 242-243:

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q(S => ‘answer(X)) -->
    whpron, vp(finite, X?S, nogap).

Warning: [...]/talk.P:242: Singleton variables: [S,X,X?S]

我需要做什么才能启动并运行这个模块?


有几个问题。运算符值(100、500 等)与标准运算符的旧值兼容,应该更高。此外,反引号/反引号(ASCII 96)在某些时候从符号变为引号字符。

通过更改操作符,我设法在 SWI prolog 中加载文件:

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:- op(1000,xfy,&).
:- op(1010,xfy,=>).
:- op(200,fx,`).

并给出命令行参数 --traditional (使反引号成为符号而不是引号字符)。

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$ swipl --traditional
Welcome to SWI-Prolog (threaded, 64 bits, version 7.4.2)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.

For online help and background, visit http://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).

?- [talk].
true.