src/HOL/Prolog/Type.thy
author wenzelm
Sat Dec 01 18:52:32 2001 +0100 (2001-12-01)
changeset 12338 de0f4a63baa5
parent 9015 8006e9009621
child 13208 965f95a3abd9
permissions -rw-r--r--
renamed class "term" to "type" (actually "HOL.type");
     1 (* type inference *)
     2 
     3 Type = Func +
     4 
     5 types ty
     6 
     7 arities ty :: type
     8 
     9 consts  bool	:: ty
    10 	nat	:: ty
    11 	"->"	:: ty => ty => ty	(infixr 20)
    12 	typeof	:: [tm, ty] => bool
    13         anyterm :: tm
    14 
    15 rules	common_typeof	"
    16 typeof (app M N) B       :- typeof M (A -> B) & typeof N A..
    17 
    18 typeof (cond C L R) A :- typeof C bool & typeof L A & typeof R A..
    19 typeof (fix F)   A       :- (!x. typeof x A => typeof (F  x) A)..
    20 
    21 typeof true  bool..
    22 typeof false bool..
    23 typeof (M and N) bool :- typeof M bool & typeof N bool..
    24 
    25 typeof (M eq  N) bool :- typeof M T    & typeof N T   ..
    26 
    27 typeof  Z    nat..
    28 typeof (S N) nat :- typeof N nat..
    29 typeof (M + N) nat :- typeof M nat & typeof N nat..
    30 typeof (M - N) nat :- typeof M nat & typeof N nat..
    31 typeof (M * N) nat :- typeof M nat & typeof N nat"
    32 
    33 rules	good_typeof	"
    34 typeof (abs Bo) (A -> B) :- (!x. typeof x A => typeof (Bo x) B)"
    35 
    36 rules	bad1_typeof	"
    37 typeof (abs Bo) (A -> B) :- (typeof varterm A => typeof (Bo varterm) B)"
    38 
    39 rules	bad2_typeof	"
    40 typeof (abs Bo) (A -> B) :- (typeof anyterm A => typeof (Bo anyterm) B)"
    41 
    42 end