Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!ucsd!sdcc6!ir230
From: ir230@sdcc6.ucsd.edu (john wavrik)
Newsgroups: comp.lang.forth
Subject: Re: Reading seq files with F83 (Help)
Message-ID: <6168@sdcc6.ucsd.edu>
Date: 17 Jan 90 22:59:53 GMT
References: <9001161917.AA02453@jade.berkeley.edu>
Organization: University of California, San Diego
Lines: 34



In response to request concerning reading of reading textfiles in F83:

Create a file BLANKS.BLK which contains only 1024 blanks and use this
to pad the end of your file:
                              COPY /B <yourfile>+BLANKS.BLK

Padding the file will insure that everything gets read. Using the /B 
switch will preserve the end of file marker in your file.  Your file
can now be treated as a file of characters.

          : FilePos  ( n -- addr )  1024 /MOD BLOCK +  ;

will give the "address" of the n-th character in the file. What happens
next depends on the type of file and what you plan to do with it. It is
easy to define:

       GetChar  which reads characters sequentially (skipping CR/LF 
                terminators and setting variables EOLN, and EOF in the 
                customary way)
                
       Readln   which reads a line at a time to a buffer

You can also read structured files of any sort, write files, and any 
combination (the variable FILE holds the address of the FCB of the file 
which to which BLOCK currently refers -- see also IN-FILE, IN-BLOCK).
Writing routines must include UPDATE (and should use FLUSH at the end).


                                                  John J Wavrik 
             jjwavrik@ucsd.edu                    Dept of Math  C-012 
                                                  Univ of Calif - San Diego 
                                                  La Jolla, CA  92093