src/Cube/cube.thy
 author clasohm Tue, 24 Oct 1995 14:45:35 +0100 changeset 1294 1358dc040edb parent 21 b5f8677e24e7 permissions -rw-r--r--
```
(*  Title:      Cube/cube.thy
ID:         \$Id\$
Author:     Tobias Nipkow

Barendregt's Lambda-Cube
*)

Cube = Pure +

types
term, context, typing 0

arities
term :: logic

consts
Abs, Prod     :: "[term, term => term] => term"
Trueprop      :: "[context, typing] => prop"          ("(_/ |- _)")
Trueprop1     :: "typing => prop"                     ("(_)")
MT_context    :: "context"                            ("")
""            :: "id => context"                      ("_ ")
""            :: "var => context"                     ("_ ")
Context       :: "[typing, context] => context"       ("_ _")
star          :: "term"                               ("*")
box           :: "term"                               ("[]")
"^"           :: "[term, term] => term"               (infixl 20)
Lam           :: "[idt, term, term] => term"          ("(3Lam _:_./ _)" [0, 0, 0] 10)
Pi            :: "[idt, term, term] => term"          ("(3Pi _:_./ _)" [0, 0] 10)
"->"          :: "[term, term] => term"               (infixr 10)
Has_type      :: "[term, term] => typing"             ("(_:/ _)" [0, 0] 5)

translations
(prop) "x:X"  == (prop) "|- x:X"
"Lam x:A. B"  == "Abs(A, %x. B)"
"Pi x:A. B"   => "Prod(A, %x. B)"
"A -> B"      => "Prod(A, _K(B))"

rules
s_b           "*: []"

strip_s       "[| A:*;  a:A ==> G |- x:X |] ==> a:A G |- x:X"
strip_b       "[| A:[]; a:A ==> G |- x:X |] ==> a:A G |- x:X"

app           "[| F:Prod(A, B); C:A |] ==> F^C: B(C)"

pi_ss         "[| A:*; !!x. x:A ==> B(x):* |] ==> Prod(A, B):*"

lam_ss        "[| A:*; !!x. x:A ==> f(x):B(x); !!x. x:A ==> B(x):* |] \
\                   ==> Abs(A, f) : Prod(A, B)"

beta          "Abs(A, f)^a == f(a)"

end

ML

val print_translation = [("Prod", dependent_tr' ("Pi", "op ->"))];

```