aboutsummaryrefslogtreecommitdiffhomepage
path: root/theories/Init/Datatypes.v
blob: a012d4e36d1da1d0a49aa4436e558959ba8b4cff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
(***********************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team    *)
(* <O___,, *        INRIA-Rocquencourt  &  LRI-CNRS-Orsay              *)
(*   \VV/  *************************************************************)
(*    //   *      This file is distributed under the terms of the      *)
(*         *       GNU Lesser General Public License Version 2.1       *)
(***********************************************************************)

(*i $Id$ i*)

Set Implicit Arguments.
V7only [Unset Implicit Arguments.].

(** [unit] is a singleton datatype with sole inhabitant [tt] *)

Inductive unit : Set := tt : unit.

(** [bool] is the datatype of the booleans values [true] and [false] *)

Inductive bool : Set := true : bool 
                      | false : bool.

Add Printing If bool.

(** [nat] is the datatype of natural numbers built from [O] and successor [S];
    note that zero is the letter O, not the numeral 0 *)

Inductive nat : Set := O : nat 
                     | S : nat->nat.

(** [Empty_set] has no inhabitant *)

Inductive Empty_set:Set :=.

(** [identity A a] is the family of datatypes on [A] whose sole non-empty
    member is the singleton datatype [identity A a a] whose
    sole inhabitant is denoted [refl_identity A a] *)

Inductive identity [A:Set; a:A] : A->Set :=
     refl_identity: (identity A a a).
Hints Resolve refl_identity : core v62.

(** [option A] is the extension of A with a dummy element None *)

Inductive option [A:Set] : Set := Some : A -> (option A) | None : (option A).

Arguments Scope option [ type_scope ].

(** [sum A B], equivalently [A + B], is the disjoint sum of [A] and [B] *)
(* Syntax defined in Specif.v *)
Inductive sum [A,B:Set] : Set
    := inl : A -> (sum A B)
     | inr : B -> (sum A B).

Infix "+" sum (at level 4, left associativity) : type_scope.
Arguments Scope sum [type_scope type_scope].

(** [prod A B], written [A * B], is the product of [A] and [B];
    the pair [pair A B a b] of [a] and [b] is abbreviated [(a,b)] *)

Inductive prod [A,B:Set] : Set := pair : A -> B -> (prod A B).
Add Printing Let prod.

Arguments Scope prod [type_scope type_scope].

Notation "x * y" := (prod x y) (at level 3, right associativity) : type_scope
  V8only (at level 30, left associativity).

Notation "( x , y )" := (pair ? ? x y) (at level 0)
  V8only "x , y" (at level 150, left associativity).

Section projections.
   Variables A,B:Set.
   Definition fst := [p:(prod A B)]Cases p of (pair x y) => x end.
   Definition snd := [p:(prod A B)]Cases p of (pair x y) => y end.
End projections. 

Notation Fst := (fst ? ?).
Notation Snd := (snd ? ?).

Hints Resolve pair inl inr : core v62.

(** Parsing only of things in [Datatypes.v] *)
V7only[
Notation "< A , B > ( x , y )" := (pair A B x y) (at level 1, only parsing, A annot).
Notation "< A , B > 'Fst' ( p )" := (fst A B p) (at level 1, only parsing, A annot).
Notation "< A , B > 'Snd' ( p )" := (snd A B p) (at level 1, only parsing, A annot).
].