ss@arovane % sml
Standard ML of New Jersey v110.52 [built: Fri Jan 21 16:42:10 2005]
- (* 3.2.1 *)
- fun fact(n) =  (* assumes n >= 1 *)
=   if n = 1 then 1 else n * fact(n - 1);
val fact = fn : int -> int
- fact(11);
val it = 39916800 : int
- fact(3);
val it = 6 : int
- fun fact(1) = 1
= |   fact(n) = n * fact(n - 1);
val fact = fn : int -> int
- fact(11);
val it = 39916800 : int
- fact(3);
val it = 6 : int
- fun cycle1(L) = tl(L)@[hd(L)]; (* @see 3.1.1(f) *)
val cycle1 = fn : 'a list -> 'a list
- fun cycle1(nil) = nil
= |   cycle1(x::xs) = xs@[x]; (* use patterns *)
val cycle1 = fn : 'a list -> 'a list
- cycle1([2,3,4,5]);
val it = [3,4,5,2] : int list
- fun cycle(i,L) =
=   if i=0 then L else cycle(i-1,tl(L))@[hd(L)];
val cycle = fn : int * 'a list -> 'a list
- cycle(3,explode("abcdefghi"));
val it = [#"d",#"e",#"f",#"g",#"h",#"i",#"c",#"b",#"a"] : char list
=   if L=nil then nil
=   else hd(L)::hd(L)::dupList(tl(L));
stdIn:22.7 Warning: calling polyEqual
val dupList = fn : ''a list -> ''a list
- fun dupList(L) =
=   if L=nil then nil
=   else [hd(L),hd(L)]@dupList(tl(L));
stdIn:25.7 Warning: calling polyEqual
val dupList = fn : ''a list -> ''a list
- dupList([1,2,3]);
val it = [1,1,2,2,3,3] : int list
- fun dupList(nil) = nil
= |   dupList(x::xs) = x::x::dupList(xs);
val dupList = fn : 'a list -> 'a list
- dupList(explode("ABCDEF"));
val it = [#"A",#"A",#"B",#"B",#"C",#"C",#"D",#"D",#"E",#"E",#"F",#"F"]
  : char list
- fun length(L) =
=   if L=nil then 0
=   else 1 + length(tl(L));
stdIn:32.7 Warning: calling polyEqual
val length = fn : ''a list -> int
- length(explode("ABC"));
val it = 3 : int
- fun length(nil) = 0
= |   length(x::xs) = 1 + length(xs);
val length = fn : 'a list -> int
- length([1,2,3,4]);
val it = 4 : int
- fun power(x:real, i:int) =
=   if i=0 then 1.0
=   else x*power(x, i-1);
val power = fn : real * int -> real
- power(2.0, 3);
val it = 8.0 : real
- fun power(_, 0) = 1.0
= |   power(x, i) = x*power(x, i-1);
val power = fn : real * int -> real
- power(3.0, 2);
val it = 9.0 : real
- fun max(L) =
=   if tl(L) = nil then hd(L)
=   else
=     if hd(L) > hd(tl(L)) then max(hd(L)::tl(tl(L)))
=     else max(tl(L));
val max = fn : int list -> int
- max([2,5,7,3]);
val it = 7 : int
- fun max(x::nil) = x
= |   max(x::y::zs) =
=       if x>y then max(x::zs) else max(y::zs);
stdIn:60.5-62.45 Warning: match nonexhaustive
          x :: nil => ...
          x :: y :: zs => ...

val max = fn : int list -> int
- max([2,4,13,24,11,0]);
val it = 24 : int
- (* fun f(a:int, b,c,d,e) = ...
= a. "if a<b+c then d else e"
=    a<b+c -> b:int,c:int
=    ... d else e -> d:X, e:X
= b. if a<b then c else e -> b:int, c:X, e:X
= c. if a<b then b+c else d+e -> b:int, c:int, d:int, e:int
= d. if a<b then b<c else d -> b:int, c:int, d:int
= e. if b<c then a else c+d -> c:int, d:int, b:int
= f. if b<c then d else e -> b:X, c:X, d:Y, e:Y
= g. if b<c then d+e else d*e -> b:X, c:X, d:Y, e:Y
= *)
-