Notes from 341 quiz section (9/30/97)
=====================================

* admin
  - course web:  http://www.cs.washington.edu/education/courses/cse341
  - subscribe to mailing list
  - e-mail (put 341 somewhere in subject line, please!)

* running ML (SML/NJ)
  - use xterms (e.g. orcas.cs.washington.edu) in Sieg 329
  - add sml's path in .cshrc (or .mycshrc)
      set path = ($path "/cse/courses/misc_lang/axp/sml/bin")
  - type "sml"
  - exit with <control>-d
  - loading files
    - use("myfile.sml");    (at SML prompt)
    - sml < "myfile.sml"    (from command line)

* basic types
  - integers (int)
  - reals (real)
  - booleans: true, false (bool)
  - strings (string)
  - characters (char)
    - new addition, NOT in ML book!
    - #"b"

* declaring types
  - shown with `:' followed by type
  - "x : int" is a variable of type integer
  
* arithmetic operators
  - usual for math:     +  -  *
  - integer division:   mod  div
  - real division:      /

* lists
  - examples
    - [1, 2, 3]
    - [] = empty list, also written:  nil
    - [["homer", "marge"], ["bart"]]
  - elements must be same type!
  - operators
    - append (@)
      - combines two lists
      - [1,2] @ [3,4] = [1,2,3,4]
  - functions
    - cons (::)
      - prepends an element onto a list
      - 1 :: [2,3,4] = [1,2,3,4]
    - head (hd)
      - return first element
      - hd([1,2,3,4]) = 1   (not [1]!)
    - tail (tl)
      - return everything but first element
      - tl([1,2,3,4]) = [2,3,4]
    - null
      - check for empty list
      - null([]) = true, null([5,6]) = false

* strings and characters
  - concat (^) -- "ab" ^ "cd" = "abcd"
  - explode
    - turns a string into a list of characters
    - explode("hi") = [#"h", #"i"]
  - implode (inverse of explode)
  - ord
    - ascii value of a character -- ord(#"a") = 97
  - chr (inverse of ord)

* functions
  - expect lots of recursion
  - fun double(x) = 2 * x;
    - valid, but only works for integers
  - fun square(x) = x * x;
    - NOT valid -- can't infer whether x is integer or real
    - this would work:  fun square(x:int) = x * x;

* comments
  - "(*" at the beginning, "*)" at the end

* ML quirks
  - unary negation written ~5, not -5
  - boolean operators
    - "andalso" and "orelse", instead of "and" and "or"
    - beware: "and" *is* a keyword, but has another meaning
  - if-then-else
    - MUST have the "else" part
    - similar to C's construct:  if a ? b : c;
  - parentheses in function calls are optional (e.g. "F x" means "F(x)")

* reading
  - above notes taken from ch. 0-5 in blue ML book