Oct 13, 2003
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- More on ML: topics covered today
	- input/output
		- among the impure features of ML
	- use of "print" command
		- only prints strings!
		- use Int.toString, Real.toString etc.
		  to get proper casting
		- use "carets" (^) for string concatenation
	- using pre-defined ML structures
		- TextIO, Char, String
		- how to prevent over-riding of
		  functions
	- reading from files, tokenizing
	- writing to files

------------------------------
- print "hello";
helloval it = () : unit
- print 23;
stdIn:18.1-18.9 Error: operator and operand don't agree [literal]
  operator domain: string
  operand:         int
  in expression:
    print 23
- print(Int.toString(23) ^ "\n");
------------------------------
open TextIO;

val myfile = openIn("input.txt");

fun readeverything(f) =
   if endOfStream(f) then nil
   else inputLine(f)::readeverything(f);

fun breakasingleline(s)
        = String.tokens Char.isSpace s;

val s = readeverything(myfile);
map breakasingleline s;

closeIn(myfile);
------------------------------
val myfile = openOut("output.txt");

output(myfile,"hidden treaasure is buried here\n");

closeOut(myfile);