Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!uunet!mcsun!unido!ecrc!ecrc!thom
From: thom@ecrc.de (Thom Fruehwirth)
Newsgroups: comp.lang.prolog
Subject: Re: why do i need an extra carridge return?
Message-ID: <1991Apr30.143208.13228@ecrc.de>
Date: 30 Apr 91 14:32:08 GMT
References: <9104262300.AA24421@thunder.LakeheadU.Ca> <1991Apr29.102537.12322@canon.co.uk>
Sender: news@ecrc.de
Reply-To: thom@ecrc.de (Thom Fruehwirth)
Organization: ecrc
Lines: 30

Bill Imlah proposes
  
>  read_line(L):-
>   	get_chars([],L).
>
>   get_chars(IN,OUT):-
>	get0(C),
>	get_rest(C,IN,OUT).
>
>   get_rest(10,L,L):-
>	!.
>   get_rest(C,IN,[C|OUT]):-
>	get_chars(IN,OUT).


Observing that the first argument of get_chars/2 will be always bound to '[]'
when called by read_line/1, we can remove this argument. As get_chars/2 is
defined by a single clause, we can unfold it away:

   read_line(L):-
	get0(C),
	get_rest(C,L).

   get_rest(10,[]):-
	!.
   get_rest(C,[C|OUT]):-
	get0(C1),
	get_rest(C1,OUT).

thom