CODEWITHSUNDEEP
prolog
Topological Sort
Topological Sort

Reputation: 2787

print_term writing to a file in PROLOG

In this mcve]

test :-                         
  tell('junk.txt'),
  print_term(
       examples([this,is,a,really,long,example,list],
             [made,of,lists,atoms,and,including,terms(involving,parentheses,like,this)]),
       []),
  told.

SWI-PROLOG does print the term to the screen neatly in the print_term way, but won't print it to the file. How do I redirect the output?

Upvotes: 1

Views: 98

Answers (1)

gusbro
gusbro

Reputation: 22585

You may use current_output/1 to get the current Stream and then pass it to print_term/2 in its Options parameter:

test :-                         
  tell('junk.txt'),
  current_output(Stream),
  print_term(
       examples([this,is,a,really,long,example,list],
             [made,of,lists,atoms,and,including,terms(involving,parentheses,like,this)]),
       [output(Stream)]),
  told.

I believe all those Edinburgh style predicates that deal with files are in maintenance mode and you now may prefer to use ISO stream predicates.

Upvotes: 1

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