Syntax error unexpected end of file prolog - Исправление ошибок и поиск оптимальных решений проблем

Error and warning messages from programming systems like
SWI Prolog tell you that there is (or may be) a problem,
but they can be a little cryptic in terms of telling you
what the problem is. The following table is intended
to demystify the messages.

Message Likely cause(s) ERROR: Out of local stack Usually infinite recursion.
Look at your recursive rules and ensure that there is some
provision to stop the recursion from going on for ever.

Warning: (test.pl:1):
        Singleton variables: [Cihld]

Means that in the program file test.pl,
at line 1 (that’s the :1), you have used a
variable name that not used anywhere else in that rule
(or fact). Can mean a spelling mistake, as in this case —
Cihld should presumably be Child.
However, it could just be that you really only wanted to
use the variable once, as with Someone, in
happy(Person) :- loves(Someone, Person).
In this case, you can get rid of the warning message by
putting an underscore in front of the singleton variable:
happy(Person) :- loves(_Someone, Person).

Warning: (thing.pl:3:31):
        Redefined static procedure rich/1

means that rich was previously defined,
and you have now loaded a new definition of it via
a consult operation. This will have
cleared out the previous definition of rich.

Warning: (/Users/billw/or.pl:6):
        Clauses of rich/1 are not together in the source-file

means that it expects all the clauses for a each
procedure to be together, and for procedure rich
this was not the case. Could have been intentional (which is
not to say a good idea) or maybe you goofed up and e.g.
repeated bits of code for rich in different
places in your source file.

ERROR: /Users/billw/thing.pl:1:
  No permission to redefine built-in predicate `assert/1'
  Use :- redefine_system_predicate(+Head) if redefinition is intended

This means that you have tried to redefine a system predicate.
It is usually a very bad idea to redefine a system predicate, as it
means that any other code that calls the system predicate may end
up using your definition, which might be entirely inappropriate.
It is usually better to think of another name for your predicate:
perhaps make_assertion instead of assert
in the example above.
If you absolutely have to use the name reserved for the system
predicate for some very good reason, you can do this by inserting
the directive

:- redefine_system_predicate(+Head).

e.g.

:- redefine_system_predicate(assert/1).

before the point where you begin to redefine the system predicate.

ERROR: /import/diskname/1/yourlogin/filename.pl:6:
        source_sink `nlp-basis.pro' does not exist
Warning: /import/diskname/1/yourlogin/filename.pl:6:
        Goal (directive) failed: user:[nlp-basis.pro]

This is telling you something like the following: you tried to use
a directive like :- ['nlp-basis.pro'].
to load some extra code into
Prolog, but there was no such file available. This could happen
either because, although the file exists, it’s in another directory,
or because you mis-spelled the filename. In this case, the file
is one that is often used in COMP9414 nlp assignments, and it is
spelled nlpbasis.pro not nlp-basis.pro
— i.e. no hyphen. Solution — fix the spelling of the filename in
your code. The :6: at the end of the first and third lines of the
messages is telling you that the problem was detected at line 6
of your code file. The extra «Warning» message is about the same
problem.

ERROR: /import/kamen/1/billw/filename.pl:12:0:
      Syntax error: Unexpected end of file

This says that, from the point of view of the Prolog system, your
code stopped abruptly at line 12, without completing the rule or
fact that it was half-way through. This might be exactly what has
happened, or it might be that some syntax error in your code has
caused Prolog to get confused about what you are trying to do.

ERROR: /import/kamen/1/billw/filename.pl:92:0:
      Syntax error: Unexpected end of clause

This says that, from the point of view of the Prolog system, your
code stopped abruptly at line 92, partway through a clause. This is
similar to the previous message, but Prolog had passed the start of
a clause when the problem occurred.

ERROR: /import/kamen/1/billw/filename.pl:41:
	Full stop in clause-body?  Cannot redefine ,/2

Likely to occur with other messages, e.g. singleton variable
warnings. Probably means you have a punctuation error in a rule,
something like this:

likes(Person1, Person2) :- friendly(Person1).
                           shared_interests(Person1, Person2),
                           pleasant(Person2).

There should be a comma, not a full stop, at the end of the first line.

ERROR: predname/1: Arguments are not sufficiently instantiated

You have called a predicate, predname, probably a
predefined one, and
you supplied an argument that was a variable that is yet bound,
where it doesn’t make sense to supply an unbound variable. For
example, tab(N) (which prints N spaces)
doesn’t make sense if N is not bound to a non-negative
whole number. The argument must be bound at the time the goal is
evaluated — it is not good enough to supply a value via a later
goal. The /1 refers to the number of arguments that
predname takes, in this case 1, but will vary according
to the number of arguments you provide to the particular predicate.
Like the preceding example errors, this one is likely to come, in
practice, with a filename:linenum:position to tell you where in
your program the problem is located.

ERROR: predname/1: Type error: `character' expected, found `abc'

Some Prolog built-in predicates insist on a particular type of
argument — maybe integer, or string, for example. In this case,
the predicate predname was expecting a single character, but
you provided the string 'abc'.
Like preceding example errors, this one is likely to come, in
practice, with a filename:linenum:position to tell you where in
your program the problem is located.

I plan to add to the table as I encounter more such messages.
Suggestions welcome, please send a cut-and-paste of the message,
the dialogue with SWI Prolog that generated it,
and the Prolog code as an attachment. This is not a free debugging service,
but I’ll try to include such examples in this list.

Источник

У пролога есть ряд функций, обеспечивающих ввод и вывод:

read/1 осуществляет ввод терма с входного потока, на прологе они завершаются точкой. Термами являются, например, числа, строки (в одинарных кавычках) и списки (в том числе списки символов и кодов символов).
readln/1 считывает символы до конца строки, формируя список слов (в одинарных кавычках);
get_char/1 считывает с потока один символ, используя синхронный ввод (если ввод осуществляется с клавиатуры, то функция не начнет работу, пока пользователь не нажмет Enter);

Но мой взгляд, достаточно удобно обрабатывать строки на SWI Prolog в виде списка кодов символов (они хранятся при этом в юникоде). Для ввода строк я использую вот функцию rd_line:

%% считывает список кодов с текущего устройства ввода
rd_line(Str):-
	get_code(H), (
		code_type(H, end_of_line), !, Str = [];
		code_type(H, end_of_file), !, Str = [];
		Str = [H|T], rd_line(T)
	).

Тут вызывается функция get_code, возвращающая код символа (аналогично get_char). Если текущий символ представляет собой конец строки или файла — результатом является пустая строка (пустой список кодов). В противном случае выполняется рекурсивный вызов для считывания остальных символов.

Если требуется осуществить ввод из файла — можно установить файл в качестве основного устройства ввода. После этого функции read и т.п. будут работать с ним точно также, как с буфером клавиатуры или экраном:

see/1, принимает ‘имя файла’, открывает файл для чтения, устанавливает его в качестве текущего потока ввода. После вызова предиката весь ввод осуществляется с открытого файла;
seen/0, закрывает файл, ассоциированный с текущим потоком ввода. После вызова этого предиката ввод осуществляется с клавиатуры;
tell/1, тоже самое, что see, но открывает файл для записи и устанавливает в качестве потока вывода;
told/0, закрывает файл открытый tell. После вызова, весь вывод попадает на экран.

Такой вариант не сработает если вам надо работать одновременно с несколькими файлами. В этом случае надо использовать версии функции read, get_char и т.п., принимающие имя открытого файлового потока в качестве дополнительного аргумента. Открыть потом можно функцией open, а закрыть — close, работа с потоками в SWI Prolog мало отличается от других языков.

В вашем случае строки не считывались, т.к. вы используете функцию read, которая считывает термы. Поставьте точки в конце строк и она их считает.

Источник

using stream function to read term in a txt file all example in forum failed ,to read term in txt,why this powerful development tool can’t do this easy work,

I don’t know what kind of problem are you experiencing. As of my experience Visual Prolog 7.4 is really awesome and simple compared to other lower version..

Can you please share the code that you’ve tried and which caused the failure for you ?

Example #1 :

If you are trying to read a data from file and want to consult with the internal Data base, here is the way,

Code: Select all

%Define a database
class facts - myTerm
    myTerm1 : (string, string, integer).
    myTerm2 : (integer, string, integer).
    myTerm3 : (integer).
    myTerm4 : (integer, char).
 
predicates
    onPushButtonClick : button::clickResponder.
clauses
    onPushButtonClick(_Source) = button::defaultAction:-
        %Consult it - this will bring all the data from file to IDB
        file::consult(@"E:Term_Input.txt", myTerm),      
        !.

File data : E:Term_Input.txt
myTerm1(«Welcome», «To», 1)
myTerm1(«Nice», «see», 1)
myTerm2(10, «Ten», 1)
myTerm2(20, «Twenty», 1)
myTerm3(100)
myTerm3(200)
myTerm4(100, ‘A’)
myTerm4(200, ‘B’)

Example #2:

To read a data from one file and write into another file,

Code: Select all

predicates
    copyTextStream : (inputStream In, outputStream Out).
clauses
    copyTextStream(In, Out) :-
        if not(In:endOfStream()) then
            Out:write(In:readline(), "n"),
            copyTextStream(In, Out)
        end if.
 
 
predicates
    onPushButtonClick : button::clickResponder.
clauses
    onPushButtonClick(_Source) = button::defaultAction:-
        InputFile = inputStream_file::openFile8("E:\test.txt"),        %Input file
        OutputFile = outputStream_file::openFile8("E:\test2.txt"),  %Output file
        copyTextStream2(InputFile, OutputFile),                            %Calling place for looping
        %You must close the stream after you complete your progress
        InputFile:close(),                                       
        OutputFile:close(),
        !.

At the end, whatever the data reside on the Input file will be written on the output file —

Источник