[PPL-devel] Re: [SWIPL] Unwanted prompt in the output

[Roberto Bagnara]

Jan Wielemaker wrote:
> On Mon, Oct 25, 2004 at 12:52:04PM +0200, Roberto Bagnara wrote:
> 
>>I have question: if I create a file that contains
>>only a blank line (i.e., "\n") and I call it `test'
>>and I do `pl <test >out', the `out' file contains
>>the string "1 ?- |    ".  Notice that, to avoid
>>ambiguities I am using the C syntax for strings,
>>so by omitting "\n" I imply that the line above
>>is not terminated.  However, the problem is the
>>presence of "|    ", not the absence of the
>>end-of-line character.
>>
>>If I modify the `test' file so that it contains two lines,
>>one blank as before followed by one containing "halt.\n"
>>and I do the same thing as before, `out' will then
>>contain "1 ?- ", i.e., without the vertical bar.
>>Is this behavior the intended one?  I have tested
>>with several other Prolog systems and they do not
>>seem to make this kind of distinction between EOF
>>on input or an explicit "halt." occurring in it.
> 
> 
> I'd have to do some tracing and debugging to find the why.  Actually I
> think there should be no prompt (at least by default) if the input is
> not associated to a terminal.

Hi Jan,

that is exactly what I was thinking: if there is no terminal
there should be no prompt.

> For the moment, I guess using the
> prompt/2 command to kill the prompt is the most sensible thing to
> do.

Will do as you suggest.
Thanks a lot,

     Roberto

-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it