Re: read from file

[Vic Bancroft]

address@hidden wrote:

> hi,
>  
Aloha

> i want to read data from the file (data.txt). and want to use these prolog 
> predicate like
> a(book)
> a(computer)
> a(phone)
> a(pen)
> a(pencil)
>  
Unless you use a read option for end_of_term, your term data should have 
the 'dot' delimeter, e.g.,

   a(book).
   a("computer").
   a("phone").
   a('pen').
   a('pencil').

Also note the distinction between an list of characters (using the 
double quote) and an atom (using the single quote).  This is most easily 
seen using the writeq/1 predicate, as in,

   terms(A) :-
       see(A),
       repeat,
       read(B),
       writeq(B),
       nl,
       (   B = end_of_file ->
           true, !
       ;   fail
       ),
       seen.

This predicate results in the output,

 | ?- terms( 'term_data.txt' ).
 a(book)
 a([99,111,109,112,117,116,101,114])
 a([112,104,111,110,101])
 a(pen)
 a(pencil)
 end_of_file

 yes

Did you really need to use read_atom/1 or perhaps read_token/1 ?

more,
l8r,
v


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