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How to input while using predicate 'read'?

Since be new to Prolog, these days I was doing the exercises following the book Adventure in Prolog.
But now I meet with an newbie question, how to input while using 'read'.


?- read(X).
a.

X = a ;
no
?- read(Y).
b;
.
.

Y = b ; . ;
no
?- read(Z).
test a test.
syntax_error
407
Unexpected operator
While executing: read_term$/3
Read buffer: test a **NEAR HERE** test.


File: user_in Line 8
Call stack:
- read_term/3;- catch/3;+ catch/3;--- top of stack ---

?-


Since Adventure in Prolog is my first Prolog book, I even don't know how to input while using read.
An 'Enter' can not finish the input, so I tries a '.', and it seems work.
When I tries ';', more input lines seems appeared, and only double '.' can end the input.
And when I tries to add a space between the words I inputed, it reports syntax_error 407.

What cause the problem? And by the way, where I can find a complete introduce for all the Amzi! Prolog Builtin Predicates?
Tagged:

Comments

  • read/1 reads a valid Prolog term, ending with a period. So it must be formatted as if you were writing it in code. So read(X) will bind X to the term if it's valid. Otherwise you get an error. It gets a bit confusing when you use 'operators'. When you read about operators you will understand. The ';' is an operator in Prolog.

    The build-in predicates of Amzi! are all in http://www.amzi.com/manuals/amzi/amzidoc.htm. It should be in your distribution as well. They are organized by category, but if you click 'index' on the table of content you will see an alphabetical listing.
  • Examples: read(X) will read: sue. (an atom), 47. (an integer), location(kitchen, sink). (a term). X. (a variable) a + b. (a term using an operator). Anything else is an error.
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