add dep2-assist

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Stephen Chang 2017-08-04 14:31:29 -04:00
parent bbb6b0a694
commit eae7e14c44
2 changed files with 924 additions and 0 deletions

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@ -0,0 +1,629 @@
#lang turnstile/lang
; second attempt at a basic dependently-typed calculus
; initially copied from dep.rkt
; Π λ ≻ ⊢ ≫ → ∧ (bidir ⇒ ⇐) τ⊑
(provide (rename-out [#%type *])
Π
= eq-refl eq-elim
Nat (rename-out [Zero Z][Succ S]) nat-ind #;nat-rec
λ (rename-out [app #%app]) ann
define define-type-alias
)
;; TODO:
;; - map #%datum to S and Z
;; - rename define-type-alias to define
;; - add "assistant" part
;; - provide match and match/lambda so nat-ind can be fn
;; - eg see https://gist.github.com/AndrasKovacs/6769513
;; - add dependent existential
;; - remove debugging code?
;; #;(begin-for-syntax
;; (define old-ty= (current-type=?))
;; (current-type=?
;; (λ (t1 t2)
;; (displayln (stx->datum t1))
;; (displayln (stx->datum t2))
;; (old-ty= t1 t2)))
;; (current-typecheck-relation (current-type=?)))
;(define-syntax-category : kind) ; defines #%kind for #%type
;; set Type : Type
;; alternatively, could define new base type Type,
;; and make #%type typecheck with Type
(begin-for-syntax
(define debug? #f)
(define type-eq-debug? #f)
(define debug-match? #f)
;; TODO: fix `type` stx class
;; (define old-type? (current-type?))
;; (current-type?
;; (lambda (t) (or (#%type? t) (old-type? t))))
(define old-relation (current-typecheck-relation))
(current-typecheck-relation
(lambda (t1 t2)
(when type-eq-debug?
(pretty-print (stx->datum t1))
(pretty-print (stx->datum t2)))
;; assumed #f can only come from (typeof #%type)
;; (so this wont work when interacting with untyped code)
(or (and (false? (syntax-e t1)) (#%type? t2)) ; assign Type : Type
(old-relation t1 t2)))))
(define-for-syntax Type ((current-type-eval) #'#%type))
(define-internal-type-constructor ) ; equiv to Π with no uses on rhs
(define-internal-binding-type ) ; equiv to Π with #%type for all params
;; Π expands into combination of internal →- and ∀-
;; uses "let*" syntax where X_i is in scope for τ_i+1 ...
;; TODO: add tests to check this
(define-typed-syntax (Π ([X:id : τ_in] ...) τ_out)
;; TODO: check that τ_in and τ_out have #%type?
[[X X- : τ_in] ... [τ_out τ_out- #%type] [τ_in τ_in- #%type] ...]
-------
[ (∀- (X- ...) (→- τ_in- ... τ_out-)) #%type])
;; abbrevs for Π
;; (→ τ_in τ_out) == (Π (unused : τ_in) τ_out)
(define-simple-macro ( τ_in ... τ_out)
#:with (X ...) (generate-temporaries #'(τ_in ...))
(Π ([X : τ_in] ...) τ_out))
;; (∀ (X) τ) == (∀ ([X : #%type]) τ)
(define-simple-macro ( (X ...) τ)
(Π ([X : #%type] ...) τ))
;; pattern expanders
(begin-for-syntax
(define-syntax
(pattern-expander
(syntax-parser
[(_ ([x:id : τ_in] ... (~and (~literal ...) ooo)) τ_out)
#'(~∀ (x ... ooo) (~→ τ_in ... ooo τ_out))]
[(_ ([x:id : τ_in] ...) τ_out)
#'(~∀ (x ...) (~→ τ_in ... τ_out))]))))
;; equality -------------------------------------------------------------------
(define-internal-type-constructor =)
(define-typed-syntax (= t1 t2)
[ t1 t1- ty]
[ t2 t2- ty]
;; #:do [(printf "t1: ~a\n" (stx->datum #'t1-))
;; (printf "t2: ~a\n" (stx->datum #'t2-))]
; [t1- τ= t2-]
---------------------
[ (=- t1- t2-) #%type])
;; Q: what is the operational meaning of eq-refl?
(define-typed-syntax (eq-refl e)
[ e e- _]
----------
[ (#%app- void-) (= e- e-)])
;; eq-elim: t : T
;; P : (T -> Type)
;; pt : (P t)
;; w : T
;; peq : (= t w)
;; -> (P w)
(define-typed-syntax (eq-elim t P pt w peq)
[ t t- ty]
[ P P- ( ty #%type)]
[ pt pt- (app P- t-)]
[ w w- ty]
[ peq peq- (= t- w-)]
--------------
[ pt- (app P- w-)])
;; lambda and #%app -----------------------------------------------------------
;; TODO: fix `type` stx class
(define-typed-syntax λ
;; expected ty only
[(_ (y:id ...) e) ( ([x:id : τ_in] ... ) τ_out)
;; must use free-identifier=? to work with prove/define and `?`
[[x x- : τ_in] ... #,(substs #'(x ...) #'(y ...) #'e free-identifier=?) e- τ_out]
---------
[ (λ- (x- ...) e-)]]
;; both expected ty and annotations
[(_ ([y:id : τ_in*] ...) e) ( ([x:id : τ_in] ...) τ_out)
; [(_ ([y:id : τy_in:type] ...) e) ⇐ (~Π ([x:id : τ_in] ...) τ_out) ≫
#:fail-unless (stx-length=? #'(y ...) #'(x ...))
"function's arity does not match expected type"
[ τ_in* τ_in** #%type] ...
; #:when (typechecks? (stx-map (current-type-eval) #'(τ_in* ...))
#:when (typechecks? #'(τ_in** ...) #'(τ_in ...))
; #:when (typechecks? #'(τy_in.norm ...) #'(τ_in ...))
; [τy_in τ= τ_in] ...
[[x x- : τ_in] ... #,(substs #'(x ...) #'(y ...) #'e) e- τ_out]
-------
[ (λ- (x- ...) e-)]]
;; annotations only
[(_ ([x:id : τ_in] ...) e)
[[x x- : τ_in] ... [e e- τ_out] [τ_in τ_in- _] ...]
-------
[ (λ- (x- ...) e-) (Π ([x- : τ_in-] ...) τ_out)]])
;; ;; classes for matching number literals
;; (begin-for-syntax
;; (define-syntax-class nat
;; (pattern (~or n:exact-nonnegative-integer (_ n:exact-nonnegative-integer))
;; #:attr val
;; #'n))
;; (define-syntax-class nats
;; (pattern (n:nat ...) #:attr vals #'(n.val ...)))
;; ; extract list of quoted numbers
;; (define stx->nat (syntax-parser [n:nat (stx-e #'n.val)]))
;; (define (stx->nats stx) (stx-map stx->nat stx))
;; (define (stx+ ns) (apply + (stx->nats ns)))
;; (define (delta op-stx args)
;; (syntax-parse op-stx
;; [(~literal +-) (stx+ args)]
;; [(~literal zero?-) (apply zero? (stx->nats args))])))
;; TODO: fix orig after subst, for err msgs
;; app/eval should not try to ty check anymore
(define-syntax app/eval
(syntax-parser
#;[(_ f . args) #:do[(printf "app/evaling ")
(printf "f: ~a\n" (stx->datum #'f))
(printf "args: ~a\n" (stx->datum #'args))]
#:when #f #'void]
[(_ f:id n P zc sc)
#:with (_ m/d . _) (local-expand #'(#%app match/delayed 'do 'nt 'ca 're) 'expression null)
#:when (free-identifier=? #'m/d #'f)
;; TODO: need to attach type?
#'(match/nat n P zc sc)]
;; TODO: apply to only lambda args or all args?
[(_ (~and f ((~literal #%plain-lambda) (x ...) e)) e_arg ...)
#:do[(when debug?
(printf "apping: ~a\n" (stx->datum #'f))
(printf "args\n")
(pretty-print (stx->datum #'(e_arg ...)))
(printf "expected type\n")
(pretty-print (stx->datum (typeof this-syntax))))]
; #:with (~Π ([X : _] ...) τ_out) (typeof #'f) ; must re-subst in type
;; TODO: need to replace all #%app- in this result with app/eval again
;; and then re-expand
; #:with ((~literal #%plain-app) newf . newargs) #'e
; #:do[(displayln #'newf)(displayln #'newargs)(displayln (stx-car #'e+))]
#:with r-app (datum->syntax (if (identifier? #'e) #'e (stx-car #'e)) '#%app)
;; TODO: is this assign-type needed only for tests?
;; eg, see id tests in dep2-peano.rkt
#:with ty (typeof this-syntax)
#:with e-inst (substs #'(app/eval e_arg ...) #'(r-app x ...) #'e free-identifier=?)
;; some apps may not have type (eg in internal reps)
#:with e+ (if (syntax-e #'ty) (assign-type #'e-inst #'ty) #'e-inst)
#:do[(when debug?
(displayln "res:--------------------")
(pretty-print (stx->datum #'e+))
;; (displayln "actual type:")
;; (pretty-print (stx->datum (typeof #'e+)))
;; (displayln "new type:")
;; (pretty-print (stx->datum (substs #'(e_arg ...) #'(X ...) (typeof #'e+))))
;; (displayln "res expanded:------------------------")
;; (pretty-print
;; (stx->datum (local-expand (substs #'(e_arg ...) #'(x ...) #'e) 'expression null)))
(displayln "res app/eval re-expanding-----------------------"))]
#:with ((~literal let-values) () ((~literal let-values) () e++))
(local-expand
#'(let-syntax (#;[app (make-rename-transformer #'app/eval)]
#;[x (make-variable-like-transformer #'e_arg)]) e+)
'expression null)
#:do[(when debug?
(pretty-print (stx->datum #'e++))
; (pretty-print (stx->datum (typeof #'e++)))
#;(local-expand
#'(let-syntax ([app (make-rename-transformer #'app/eval)]
#;[x (make-variable-like-transformer #'e_arg)]) e+)
'expression null))]
#'e++ #;(substs #'(e_arg ...) #'(x ...) #'e)]
[(_ f . args)
#:do[(when debug?
(printf "not apping\n")
(pretty-print (stx->datum #'f))
(displayln "args")
(pretty-print (stx->datum #'args)))]
#:with f+ (expand/df #'f)
#:with args+ (stx-map expand/df #'args)
;; TODO: need to attach type?
; #:with ty (typeof this-syntax)
(syntax-parse #'f+
[((~literal #%plain-lambda) . _)
#'(app/eval f+ . args+)]
[_
#'(#%app- f+ . args+)])]))
;; TODO: fix orig after subst
(define-typed-syntax app
;; matching, ; TODO: where to put this?
#;[(_ f:id . args)
#:with (_ m/d . _) (local-expand #'(match/delayed 1 2 3 4) 'expression null)
#:when (free-identifier=? #'m/d #'f)
------------
[ (match/nat . args)]]
[(_ e_fn e_arg ...)
#:do[(when debug?
(displayln "TYPECHECKING")
(pretty-print (stx->datum this-syntax)))]
; #:do[(printf "applying (1) ~a\n" (stx->datum #'e_fn))]
; [⊢ e_fn ≫ (~and e_fn- (_ (x:id ...) e ~!)) ⇒ (~Π ([X : τ_inX] ...) τ_outX)]
[ e_fn e_fn- ( ([X : τ_in] ...) τ_out)]
; #:do[(printf "applying (1) ~a\n" (stx->datum #'e_fn-))]
#:fail-unless (stx-length=? #'[τ_in ...] #'[e_arg ...])
(num-args-fail-msg #'e_fn #'[τ_in ...] #'[e_arg ...])
[ e_arg e_arg- τ_in] ... ; typechecking args
-----------------------------
[ (app/eval e_fn- e_arg- ...) #,(substs #'(e_arg- ...) #'(X ...) #'τ_out)]])
#;(define-typed-syntax #%app
[(_ e_fn e_arg ...) ; apply lambda
#:do[(printf "applying (1) ~a\n" (stx->datum #'e_fn))]
[ e_fn (~and e_fn- (_ (x:id ...) e ~!)) ( ([X : τ_inX] ...) τ_outX)]
#:do[(printf "e_fn-: ~a\n" (stx->datum #'e_fn-))
(printf "args: ~a\n" (stx->datum #'(e_arg ...)))]
#:fail-unless (stx-length=? #'[τ_inX ...] #'[e_arg ...])
(num-args-fail-msg #'e_fn #'[τ_inX ...] #'[e_arg ...])
[ e_arg e_argX- ty-argX] ... ; typechecking args must be fold; do in 2 steps
#:do[(define (ev e)
(syntax-parse e
; [_ #:do[(printf "eval: ~a\n" (stx->datum e))] #:when #f #'(void)]
[(~or _:id
; ((~literal #%plain-lambda) . _)
(~= _ _)
~Nat
((~literal quote) _))
e]
;; handle nums
[((~literal #%plain-app)
(~and op (~or (~literal +-) (~literal zero?-)))
. args:nats)
#`#,(delta #'op #'args.vals)]
[((~literal #%plain-app) (~and f ((~literal #%plain-lambda) . b)) . rst)
(expand/df #`(#%app f . #,(stx-map ev #'rst)))]
[(x ...)
;; #:do[(printf "t before: ~a\n" (typeof e))
;; (printf "t after: ~a\n" (typeof #`#,(stx-map ev #'(x ...))))]
(syntax-property #`#,(stx-map ev #'(x ...)) ': (typeof e))]
[_ e] ; other literals
#;[es (stx-map L #'es)]))]
#:with (ty-arg ...)
(stx-map
(λ (t) (ev (substs #'(e_argX- ...) #'(X ...) t)))
#'(ty-argX ...))
#:with (e_arg- ...) (stx-map (λ (e t) (assign-type e t)) #'(e_argX- ...) #'(ty-arg ...))
#:with (τ_in ... τ_out)
(stx-map
(λ (t) (ev (substs #'(e_arg- ...) #'(X ...) t)))
#'(τ_inX ... τ_outX))
; #:do[(printf "vars: ~a\n" #'(X ...))]
; #:when (stx-andmap (λ (t1 t2)(displayln (stx->datum t1)) (displayln (stx->datum t2)) (displayln (typecheck? t1 t2)) #;(typecheck? t1 t2)) #'(ty-arg ...) #'(τ_in ...))
;; #:do[(stx-map
;; (λ (tx t) (printf "ty_in inst: \n~a\n~a\n" (stx->datum tx) (stx->datum t)))
;; #'(τ_inX ...) #'(τ_in ...))]
; [⊢ e_arg- ≫ _ ⇐ τ_in] ...
#:do[(printf "res e =\n~a\n" (stx->datum (substs #'(e_arg- ...) #'(x ...) #'e)))
(printf "res t = ~a\n" (stx->datum (substs #'(e_arg- ...) #'(X ...) #'τ_out)))]
#:with res-e (let L ([e (substs #'(e_arg- ...) #'(x ...) #'e)]) ; eval
(syntax-parse e
[(~or _:id
((~literal #%plain-lambda) . _)
( ([_ : _] ...) _)
(~= _ _)
~Nat)
e]
;; handle nums
[((~literal #%plain-app)
(~and op (~or (~literal +-) (~literal zero?-)))
. args:nats)
#`#,(delta #'op #'args.vals)]
[((~literal #%plain-app) . rst)
(expand/df #`(#%app . #,(stx-map L #'rst)))]
[_ e] ; other literals
#;[es (stx-map L #'es)]))
;; #:with res-ty (syntax-parse (substs #'(e_arg- ...) #'(X ...) #'τ_out)
;; [((~literal #%plain-app) . rst) (expand/df #'(#%app . rst))]
;; [other-ty #'other-ty])
--------
[ res-e #;#,(substs #'(e_arg- ...) #'(x ...) #'e) τ_out
#;#,(substs #'(e_arg- ...) #'(X ...) #'τ_out)]]
[(_ e_fn e_arg ... ~!) ; apply var
; #:do[(printf "applying (2) ~a\n" (stx->datum #'e_fn))]
[ e_fn e_fn- ty-fn]
; #:do[(printf "e_fn- ty: ~a\n" (stx->datum #'ty-fn))]
[ e_fn _ ( ([X : τ_inX] ...) τ_outX)]
; #:do[(printf "e_fn- no: ~a\n" (stx->datum #'e_fn-))
; (printf "args: ~a\n" (stx->datum #'(e_arg ...)))]
;; #:with e_fn- (syntax-parse #'e_fn*
;; [((~literal #%plain-app) . rst) (expand/df #'(#%app . rst))]
;; [other #'other])
#:fail-unless (stx-length=? #'[τ_inX ...] #'[e_arg ...])
(num-args-fail-msg #'e_fn #'[τ_inX ...] #'[e_arg ...])
[ e_arg e_argX- ty-argX] ... ; typechecking args must be fold; do in 2 steps
#:do[(define (ev e)
(syntax-parse e
; [_ #:do[(printf "eval: ~a\n" (stx->datum e))] #:when #f #'(void)]
[(~or _:id
; ((~literal #%plain-lambda) . _)
(~= _ _)
~Nat
((~literal quote) _))
e]
;; handle nums
[((~literal #%plain-app)
(~and op (~or (~literal +-) (~literal zero?-)))
. args:nats)
#`#,(delta #'op #'args.vals)]
[((~literal #%plain-app) (~and f ((~literal #%plain-lambda) . b)) . rst)
(expand/df #`(#%app f . #,(stx-map ev #'rst)))]
[(x ...)
;; #:do[(printf "t before: ~a\n" (typeof e))
;; (printf "t after: ~a\n" (typeof #`#,(stx-map ev #'(x ...))))]
(syntax-property #`#,(stx-map ev #'(x ...)) ': (typeof e))]
[_ e] ; other literals
#;[es (stx-map L #'es)]))]
#:with (ty-arg ...)
(stx-map
(λ (t) (ev (substs #'(e_argX- ...) #'(X ...) t)))
#'(ty-argX ...))
#:with (e_arg- ...) (stx-map (λ (e t) (assign-type e t)) #'(e_argX- ...) #'(ty-arg ...))
#:with (τ_in ... τ_out)
(stx-map
(λ (t) (ev (substs #'(e_arg- ...) #'(X ...) t)))
#'(τ_inX ... τ_outX))
;; #:do[(printf "vars: ~a\n" #'(X ...))]
; #:when (stx-andmap (λ (e t1 t2)(displayln (stx->datum e))(displayln (stx->datum t1)) (displayln (stx->datum t2)) (displayln (typecheck? t1 t2)) #;(typecheck? t1 t2)) #'(e_arg ...)#'(ty-arg ...) #'(τ_in ...))
;; #:do[(stx-map
;; (λ (tx t) (printf "ty_in inst: \n~a\n~a\n" (stx->datum tx) (stx->datum t)))
;; #'(τ_inX ...) #'(τ_in ...))]
; [⊢ e_arg ≫ _ ⇐ τ_in] ...
; #:do[(printf "res e2 =\n~a\n" (stx->datum #'(#%app- e_fn- e_arg- ...)))
; (printf "res t2 = ~a\n" (stx->datum (substs #'(e_arg- ...) #'(X ...) #'τ_out)))]
;; #:with res-e (syntax-parse #'e_fn-
;; [((~literal #%plain-lambda) . _) (expand/df #'(#%app e_fn- e_arg- ...))]
;; [other #'(#%app- e_fn- e_arg- ...)])
--------
[ (#%app- e_fn- e_arg- ...) τ_out
#;#,(expand/df (substs #'(e_arg- ...) #'(X ...) #'τ_out))]])
(define-typed-syntax (ann e (~datum :) τ)
[ e e- τ]
--------
[ e- τ])
;; (define-typed-syntax (if e1 e2 e3) ≫
;; [⊢ e1 ≫ e1- ⇒ _]
;; [⊢ e2 ≫ e2- ⇒ ty]
;; [⊢ e3 ≫ e3- ⇒ _]
;; #:do[(displayln #'(e1 e2 e3))]
;; --------------
;; [⊢ (#%app- void-) ⇒ ty])
;; top-level ------------------------------------------------------------------
;; TODO: shouldnt need define-type-alias, should be same as define
(define-syntax define-type-alias
(syntax-parser
[(_ alias:id τ);τ:any-type)
#'(define-syntax- alias
(make-variable-like-transformer #'τ))]
#;[(_ (f:id x:id ...) ty)
#'(define-syntax- (f stx)
(syntax-parse stx
[(_ x ...)
#:with τ:any-type #'ty
#'τ.norm]))]))
(define-typed-syntax define
[(_ x:id (~datum :) τ e:expr)
[ e e- τ]
#:with y (generate-temporary #'x)
#:with y+props (transfer-props #'e- #'y #:except '(origin))
--------
[ (begin-
(define-syntax x (make-rename-transformer #'y+props))
(define- y e-))]]
[(_ x:id e)
;This won't work with mutually recursive definitions
[ e e- _]
#:with y (generate-temporary #'x)
#:with y+props (transfer-props #'e- #'y #:except '(origin))
--------
[ (begin-
(define-syntax x (make-rename-transformer #'y+props))
(define- y e-))]]
#;[(_ (f [x (~datum :) ty] ... (~or (~datum ) (~datum ->)) ty_out) e ...+)
#:with f- (add-orig (generate-temporary #'f) #'f)
--------
[ (begin-
(define-syntax- f
(make-rename-transformer ( f- : ( ty ... ty_out))))
(define- f-
(stlc+lit:λ ([x : ty] ...)
(stlc+lit:ann (begin e ...) : ty_out))))]])
;; peano nums -----------------------------------------------------------------
(define-base-type Nat)
(struct Z () #:transparent)
(struct S (n) #:transparent)
(define-typed-syntax Zero
[_:id --- [ (Z) Nat]])
(define-typed-syntax (Succ n)
[ n n- Nat]
-----------
[ (S n-) Nat])
#;(define-typed-syntax (sub1 n)
[ n n- Nat]
#:do[(displayln #'n-)]
-----------
[ (#%app- -- n- 1) Nat])
;; generalized recursor over natural nums
;; (cases dispatched in #%app)
;; (define- (nat-ind- P z s n) (#%app- void))
;; (define-syntax nat-ind
;; (make-variable-like-transformer
;; (assign-type
;; #'nat-ind-
;; #'(Π ([P : (→ Nat #%type)]
;; [z : (app P Zero)]
;; [s : (Π ([k : Nat]) (→ (app P k) (app P (Succ k))))]
;; [n : Nat])
;; (app P n)))))
#;(define-type-alias nat-ind
(λ ([P : ( Nat #%type)]
[z : (P Z)]
[s : (Π ([k : Nat]) ( (P k) (P (S k))))]
[n : Nat])
#'(#%app- nat-ind- P z s n)))
(struct match/delayed (n P zc sc))
#;(define-syntax match/eval
(syntax-parser
[(_ n zc sc) #:do[(printf "matching: ~a\n" (stx->datum #'n))] #:when #f #'(void)]
[(_ ((~literal #%plain-app) z0:id) zc sc)
#:with (_ z1) (local-expand #'(Z) 'expression null)
#:when (free-identifier=? #'z0 #'z1)
#'zc]
[(_ ((~literal #%plain-app) s0:id m) zc sc)
#:with (_ s1 . _) (local-expand #'(S 'dont-care) 'expression null)
#:when (free-identifier=? #'s0 #'s1)
#:when (displayln 2)
#`(app sc (nat-rec #,(typeof #'zc) zc sc m))]
[(_ n zc sc) #'(match/delayed n zc sc)]))
;; this is an "eval" form; should not do any more type checking
;; otherwise, will get type errs some some subexprs may still have uninst tys
;; eg, zc and sc were typechecked with paramaterized P instead of inst'ed P
(define-syntax match/nat
(syntax-parser
[(_ n P zc sc)
#:do[(when debug-match?
(printf "match/nating: ~a\n" (stx->datum #'(n P zc sc)))
#;(printf "zc ty: ~a\n" (stx->datum (typeof #'zc)))
#;(printf "sc ty: ~a\n" (stx->datum (typeof #'sc))))]
#:when #f #'(void)]
[(_ (~and n ((~literal #%plain-app) z0:id)) P zc sc)
#:with (_ z1) (local-expand #'(#%app Z) 'expression null)
#:when (free-identifier=? #'z0 #'z1)
#:do [(when debug-match? (displayln 'zc))]
;; #:when (printf "match eval res zero ety: ~a\n" (stx->datum (typeof this-syntax)))
;; #:when (printf "match eval res zero ty: ~a\n" (stx->datum (typeof #'zc)))
(assign-type #'zc #'(app/eval P n))]
[(_ (~and n ((~literal #%plain-app) s0:id m)) P zc sc)
#:with (_ s1 . _) (local-expand #'(#%app S 'dont-care) 'expression null)
#:when (free-identifier=? #'s0 #'s1)
#:with ( ([_ : _] ...) τ_out) (typeof #'sc)
#:do[(when debug-match? (displayln 'sc))]
;; #:when (printf "match eval res succ ety: ~a\n" (stx->datum (typeof this-syntax)))
;; #:when (printf "match eval res succ ty: ~a\n" (stx->datum (typeof #'sc)))
;; #:when (printf "match eval res succ ty: ~a\n" (stx->datum (typeof #'(app/eval (app/eval sc m) (match/nat m P zc sc)))))
; #`(app sc m (nat-rec #,(typeof #'zc) zc sc m))]
; #:with ty (typeof this-syntax)
(assign-type
#`(app/eval #,(assign-type #'(app/eval sc m) #'τ_out) (match/nat m P zc sc))
#'(app/eval P n))
; #'res
; (if (syntax-e #'ty) (assign-type #'res #'ty) #'res)
#;(assign-type #`(app/eval #,(assign-type #'(app/eval sc m) #'τ_out) (match/nat m P zc sc)) (typeof this-syntax))]
[(_ n P zc sc)
#:do[(when debug-match? (displayln "delay match"))]
(assign-type #'(#%app match/delayed n P zc sc) #'(app/eval P n))]))
#;(define-typed-syntax (nat-rec ty zc sc n)
[ ty ty- #%type]
[ zc zc- ty-] ; zero case
[ sc sc- ( ty- ty-)] ; succ case
[ n n- Nat]
;; #:with res
;; (syntax-parse #'n-
;; [aaa #:do[(printf "matching: ~a\n" (stx->datum #'aaa))] #:when #f #'(void)]
;; [((~literal #%plain-app) (~literal Z)) #'zc-]
;; [((~literal #%plain-app) (~literal S) m) #'(app sc- (nat-rec zc- sc- m))])
--------------------
; [⊢ (match/eval n- zc- sc-) ⇒ ty-])
[ (match/nat n-
zc-
(λ ([n-1 : Nat][rec : ty-])
(sc- rec)))
ty-])
(define-typed-syntax (nat-ind P z s n)
[ P P- ( Nat #%type)]
[ z z- (app P- Zero)] ; zero
[ s s- (Π ([k : Nat]) ( (app P- k) (app P- (Succ k))))] ; succ
[ n n- Nat]
;; #:with res (if (typecheck? #'n- (expand/df #'Z))
;; #'z-
;; #'(s- (nat-ind P- z- s- (sub1 n-))))
----------------
[ (match/nat n-
P-
z-
s-
#;(λ ([n-1 : Nat][rec : (app P- n-)])
(app s- n-1 rec #;(nat-ind P- z- s- n-1))))
(app P- n-)])
; [≻ (P- d-)])
;; proof assistant
(provide prove ? refine)
(struct ?? ())
(define-for-syntax ?+ (stx-cadr (local-expand #'(??) 'expression null)))
(define-typed-syntax ?
[(_ ty)
#:with x (generate-temporary)
#:do[(current-hole #'x)]
-----
[ #,?+ ty]]
[_:id ty
#:with x (generate-temporary)
#:do[(current-hole #'x)]
-----
[ #,?+]])
(begin-for-syntax
(define current-ty (make-parameter #f))
(define current-hole (make-parameter #f))
(define current-expr (make-parameter #f))
(define (update-expr e)
(set-expr (subst e ?+ (current-expr) free-identifier=?)))
(define (set-expr e)
(current-expr e)
(printf "current proof: ~a\n" (stx->datum (current-expr))))
(define (mk-hole)
(current-hole (generate-temporary))
(current-hole)))
(define-syntax prove
(syntax-parser
[(_ ty)
#:do[(current-ty ((current-type-eval) #'ty))]
#:when (local-expand #'(? ty) 'expression null)
#:do[(set-expr #'?)]
#'(void)]))
(define-typed-syntax refine
[(_ e)
#:do[(printf "refining with: ~a\n" (stx->datum #'e))]
#:with ty (current-ty)
#:with e0 (subst #'e #'? (current-expr) free-identifier=?)
[ e0 e0- ty]
#:do [(displayln "ok.")
(set-expr #'e0)
(let ([x (generate-temporary)])
(when ((current-type=?) #'e0 (subst #'x #'? #'e0 free-identifier=?))
(displayln "qed.")))]
-------
[ (void) ty]])

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@ -0,0 +1,295 @@
#lang s-exp "../dep2-assist.rkt"
(require "rackunit-typechecking.rkt")
; Π → λ ∀ ≻ ⊢ ≫ ⇒
;; examples from Prabhakar's Proust paper
(prove ( (A B C) ( ( A B) ( B C) ( A C))))
(refine (λ (a b c) ?))
(refine (λ (f g) ?))
(refine (λ (x) ?))
; (refine (f ?)) ; wrong, g first
(refine (g ?))
(refine (f ?))
(refine x)
;; ;; the following examples to not require type-level eval
;; (check-type (λ ([x : *]) x) : (Π ([x : *]) *))
;; (typecheck-fail ((λ ([x : *]) x) (λ ([x : *]) x))
;; #:verb-msg "expected *, given (Π ([x : *]) *)")
;; (check-type (λ ([A : *][B : *])
;; (λ ([x : A])
;; (λ ([y : (→ A B)])
;; (y x))))
;; : (∀ (A B) (→ A (→ (→ A B) B))))
;; ;; check alpha equiv
;; ;; TODO: is this correct behavior?
;; (check-type (λ ([A : *][B : *])
;; (λ ([x : A])
;; (λ ([y : (→ A B)])
;; (y x))))
;; : (∀ (Y Z) (→ Y (→ (→ Y Z) Z))))
;; (check-type (λ ([Y : *][Z : *])
;; (λ ([x : Y])
;; (λ ([y : (→ Y Z)])
;; (y x))))
;; : (∀ (A B) (→ A (→ (→ A B) B))))
;; ;; check infer direction
;; (check-type (λ (A B) (λ (x) (λ (y) (y x))))
;; : (∀ (A B) (→ A (→ (→ A B) B))))
;; (check-type (λ (A B) (λ (x) (λ (y) (y x))))
;; : (∀ (X Y) (→ X (→ (→ X Y) Y))))
;; ;; transitivity of implication --------------------
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ B C)])
;; (λ ([g : (→ A B)])
;; (λ ([x : A])
;; (f (g x))))))
;; : (∀ (A B C) (→ (→ B C) (→ (→ A B) (→ A C)))))
;; ;; less currying
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ B C)][g : (→ A B)])
;; (λ ([x : A])
;; (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; ;; infer direction (no annotations)
;; (check-type (λ (A B C) (λ (f) (λ (g) (λ (x) (f (g x))))))
;; : (∀ (A B C) (→ (→ B C) (→ (→ A B) (→ A C)))))
;; ;; less currying
;; (check-type (λ (A B C) (λ (f g) (λ (x) (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; (check-type (λ (A B C) (λ (f g x) (f (g x))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) A C)))
;; (check-type (λ (A B C f g x) (f (g x)))
;; : (Π ([A : *][B : *][C : *][f : (→ B C)][g : (→ A B)][x : A]) C))
;; (check-type (λ (A B C f g x) (f (g x)))
;; : (Π ([X : *][Y : *][Z : *][a : (→ Y Z)][b : (→ X Y)][c : X]) Z))
;; ;; partial annotations - outer lam with no annotations
;; (check-type (λ (A B C)
;; (λ (f g)
;; (λ ([x : A])
;; (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; (check-type (λ (A B C)
;; (λ ([f : (→ B C)][g : (→ A B)])
;; (λ ([x : A])
;; (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; (typecheck-fail (ann
;; (λ (A B C)
;; (λ (f g)
;; (λ ([x : C])
;; (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; #:with-msg "expected A, given C")
;; ;; partial annotations - inner lam with no annotations
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ (f g)
;; (λ (x)
;; (f (g x)))))
;; : (∀ (A B C) (→ (→ B C) (→ A B) (→ A C))))
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ B C)])
;; (λ (g)
;; (λ (x)
;; (f (g x))))))
;; : (∀ (A B C) (→ (→ B C) (→ (→ A B) (→ A C)))))
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ B C)])
;; (λ (g)
;; (λ ([x : A])
;; (f (g x))))))
;; : (∀ (A B C) (→ (→ B C) (→ (→ A B) (→ A C)))))
;; (check-type (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ B C)])
;; (λ ([g : (→ A B)])
;; (λ (x)
;; (f (g x))))))
;; : (∀ (A B C) (→ (→ B C) (→ (→ A B) (→ A C)))))
;; ;; Peirce's Law (doesnt work)
;; (typecheck-fail (ann
;; (λ ([A : *][B : *][C : *])
;; (λ ([f : (→ (→ A B) A)])
;; (λ ([g : (→ A B)]) ; need concrete (→ A B) (not in type)
;; (f g))))
;; : (∀ (A B C) (→ (→ (→ A B) A) A)))
;; #:verb-msg "expected (∀ (A B C) (→ (→ (→ A B) A) A)), given (Π ((A : *) (B : *) (C : *)) (Π ((f : (→ (→ A B) A))) (Π ((g : (→ A B))) A)))")
;; ;; booleans -------------------------------------------------------------------
;; ;; Bool base type
;; ;; TODO: use define instead of define-type-alias
;; (define-type-alias Bool (∀ (A) (→ A A A)))
;; (check-type Bool : *)
;; ;; Bool terms
;; (define T (λ ([A : *]) (λ ([x : A][y : A]) x)))
;; (define F (λ ([A : *]) (λ ([x : A][y : A]) y)))
;; (check-type T : Bool)
;; (check-type F : Bool)
;; ;; check infer case
;; (define T2 (λ ([abool : *]) (λ ([x : abool][y : abool]) x)))
;; (define F2 (λ ([abool : *]) (λ ([x : abool][y : abool]) y)))
;; (check-type T2 : Bool)
;; (check-type F2 : Bool)
;; (define T3 : Bool (λ (abool) (λ (x y) x)))
;; (define F3 : Bool (λ (abool) (λ (x y) y)))
;; (check-type T3 : Bool)
;; (check-type F3 : Bool)
;; ;; defining `and` requires instantiating polymorphic types
;; (define and (λ ([x : Bool][y : Bool]) ((x Bool) y F)))
;; (check-type and : (→ Bool Bool Bool))
;; (define or (λ ([x : Bool][y : Bool]) ((x Bool) T y)))
;; (check-type or : (→ Bool Bool Bool))
;; (define not (λ ([x : Bool]) ((x Bool) F T)))
;; (check-type not : (→ Bool Bool))
;; ;; `And` type constructor, ie type-level fn
;; (define-type-alias And
;; (λ ([P : *][Q : *])
;; (∀ (C) (→ (→ P Q C) C))))
;; (check-type And : (→ * * *))
;; ;; And type intro (logical conj)
;; (define ∧
;; (λ ([P : *][Q : *])
;; (λ ([p : P][q : Q])
;; (λ ([C : *])
;; (λ ([f : (→ P Q C)])
;; (f p q))))))
;; (check-type ∧ : (∀ (P Q) (→ P Q (And P Q))))
;; ;; `And` type elim
;; (define proj1
;; (λ ([P : *][Q : *])
;; (λ ([e : (And P Q)])
;; ((e P) (λ ([x : P][y : Q]) x)))))
;; (define proj2
;; (λ ([P : *][Q : *])
;; (λ ([e : (And P Q)])
;; ((e Q) (λ ([x : P][y : Q]) y)))))
;; ;; bad proj2: (e A) should be (e B)
;; (typecheck-fail
;; (λ ([P : *][Q : *])
;; (λ ([e : (And P Q)])
;; ((e P) (λ ([x : P][y : Q]) y))))
;; #:verb-msg
;; "expected (→ P Q C), given (Π ((x : P) (y : Q)) Q)")
;; (check-type proj1 : (∀ (P Q) (→ (And P Q) P)))
;; (check-type proj2 : (∀ (P Q) (→ (And P Q) Q)))
;; ;; proj1, no annotations
;; (check-type (λ (P Q) (λ (e) ((e P) (λ (x y) x))))
;; : (∀ (P Q) (→ (And P Q) P)))
;; ;; proj2, no annotations
;; (check-type (λ (P Q) (λ (e) ((e Q) (λ (x y) y))))
;; : (∀ (P Q) (→ (And P Q) Q)))
;; (typecheck-fail (ann (λ (P Q) (λ (e) ((e Q) (λ (x y) x))))
;; : (∀ (P Q) (→ (And P Q) Q)))
;; #:with-msg "expected C, given P") ; TODO: err msg, fix orig
;; (typecheck-fail (ann (λ (P Q) (λ (e) ((e P) (λ (x y) y))))
;; : (∀ (P Q) (→ (And P Q) Q)))
;; #:with-msg "expected C, given Q") ; TODO: err msg
;; ;((((conj q) p) (((proj2 p) q) a)) (((proj1 p) q) a)))))
;; (define and-commutes
;; (λ ([A : *][B : *])
;; (λ ([e : (And A B)])
;; ((∧ B A) ((proj2 A B) e) ((proj1 A B) e)))))
;; ;; bad and-commutes, dont flip A and B: (→ (And A B) (And A B))
;; (typecheck-fail
;; (λ ([A : *][B : *])
;; (λ ([e : (And A B)])
;; ((∧ A B) ((proj2 A B) e) ((proj1 A B) e))))
;; #:verb-msg
;; "#%app: type mismatch: expected P, given C") ; TODO: err msg
;; (check-type and-commutes : (∀ (A B) (→ (And A B) (And B A))))
;; ;; nats -----------------------------------------------------------------------
;; (define-type-alias nat (∀ (A) (→ A (→ A A) A)))
;; (check-type nat : *)
;; (define-type-alias z (λ ([Ty : *]) (λ ([zero : Ty][succ : (→ Ty Ty)]) zero)))
;; (define-type-alias s (λ ([n : nat])
;; (λ ([Ty : *])
;; (λ ([zero : Ty][succ : (→ Ty Ty)])
;; (succ ((n Ty) zero succ))))))
;; (check-type z : nat)
;; (check-type s : (→ nat nat))
;; (define-type-alias one (s z))
;; (define-type-alias two (s (s z)))
;; (check-type one : nat)
;; (check-type two : nat)
;; (define-type-alias plus
;; (λ ([x : nat][y : nat])
;; ((x nat) y s)))
;; (check-type plus : (→ nat nat nat))
;; (check-type (λ (x y) ((x nat) y s)) : (→ nat nat nat))
;; ;; equality -------------------------------------------------------------------
;; (check-type (eq-refl one) : (= one one))
;; (typecheck-fail (ann (eq-refl one) : (= two one))
;; #:verb-msg "expected (= two one), given (= one one)")
;; (check-type (ann (eq-refl one) : (= one one)) : (= one one))
;; (check-type (eq-refl one) : (= (s z) one))
;; (check-type (eq-refl two) : (= (s (s z)) two))
;; (check-type (eq-refl two) : (= (s one) two))
;; (check-type (eq-refl two) : (= two (s one)))
;; (check-type (eq-refl two) : (= (s (s z)) (s one)))
;; ;; the following example requires recursive expansion after eval/app
;; (check-type (eq-refl two) : (= (plus one one) two))
;; (check-not-type (eq-refl two) : (= (plus one one) one))
;; ;; symmetry of =
;; (check-type (∀ (A B) (→ (= A B) (= B A))) : *)
;; (check-type
;; (λ ([A : *][B : *])
;; (λ ([e : (= A B)])
;; (eq-elim A (λ ([W : *]) (= W A)) (eq-refl A) B e)))
;; : (∀ (A B) (→ (= A B) (= B A))))
;; (check-type
;; (λ (A B)
;; (λ (e)
;; (eq-elim A (λ (W) (= W A)) (eq-refl A) B e)))
;; : (∀ (A B) (→ (= A B) (= B A))))
;; (check-not-type
;; (λ ([A : *][B : *])
;; (λ ([e : (= A B)])
;; (eq-elim A (λ ([W : *]) (= W A)) (eq-refl A) B e)))
;; : (∀ (A B) (→ (= A B) (= A B))))
;; ;; transitivity of =
;; (check-type
;; (λ ([X : *][Y : *][Z : *])
;; (λ ([e1 : (= X Y)][e2 : (= Y Z)])
;; (eq-elim Y (λ ([W : *]) (= X W)) e1 Z e2)))
;; : (∀ (A B C) (→ (= A B) (= B C) (= A C))))
;; (check-type
;; (λ (X Y Z)
;; (λ (e1 e2)
;; (eq-elim Y (λ (W) (= X W)) e1 Z e2)))
;; : (∀ (A B C) (→ (= A B) (= B C) (= A C))))
;; ;; general tests that app/eval is properly applied recursively
;; (check-type ((λ ([f : (→ * *)][x : *]) (f x))
;; (λ ([x : *]) x)
;; *)
;; : *)
;; (check-type (((λ ([f : (→ (→ * *) * *)]) f) (λ ([g : (→ * *)][x : *]) (g x)))
;; (λ ([y : *]) *)
;; *)
;; : *)