You have code that uses write/1 which writes to the predefined stream current_output but you want write/1 to write to a file. You could change all of write/1 to write/2 but there is another option.
Since write/1 writes to current_output you can temporarily substitute in another stream for current_output. How you ask. Use setup_call_cleanup/3, stream_property/2, open/4, set_stream/2 or set_output/1 and close/1. Also see Predefined stream aliases
setup_call_cleanup( ( stream_property(Original,alias(current_output)), open('file_name',write,S,), set_stream(S,alias(current_output)) ), write('Hello, World!'), ( close(S), set_stream(Original,alias(current_output)) ) )
Also note that
can be used instead of
Noted in case you read code and see this, there is no difference AFAIK.
A use case for this is when using portray/1 for which it is not uncommon to see used with write/1. I don’t have enough experience with portray/1 to claim that write/1 is commonly used with portray/1.
The specific use for which I need this is to parse ABNF to a term/structure using DCGs, then use portray/1 to convert the term/structure back into text. Then parse the created text again and check to make sure that both the outputs from portray/1 are identical, or for those in the know to reach a fixed point.
Example of using with_output_to/2 as noted by SWI for fixed_point_check/1