commit dafa992176d0376988cc879c9fdd775d9fd4d66f
parent 8656e1469d7821ad9939ca88500b15055a7d8b8b
Author: Stephen Chang <stchang@ccs.neu.edu>
Date: Tue, 30 Jun 2015 16:32:50 -0400
add stlc+(iso)recursive types
Diffstat:
6 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/tapl/README.md b/tapl/README.md
@@ -9,6 +9,7 @@ A file extends its immediate parent file.
- stlc+var.rkt
- stlc+cons.rkt
- stlc+box.rkt
+ - stlc+rec-iso.rkt
- stlc+sub.rkt
- stlc+rec+sub.rkt (also pull in tup from stlc+var.rkt)
- sysf.rkt
diff --git a/tapl/ext-stlc.rkt b/tapl/ext-stlc.rkt
@@ -1,5 +1,8 @@
#lang racket/base
(require "typecheck.rkt")
+;; prefix-in an identifier if:
+;; - it will be extended, eg #%datum
+;; - want to use racket's version in this file, eg #%app
(require (prefix-in stlc: (only-in "stlc+lit.rkt" #%app #%datum))
(except-in "stlc+lit.rkt" #%app #%datum))
(provide (rename-out [datum/tc #%datum]
diff --git a/tapl/notes.txt b/tapl/notes.txt
@@ -1,6 +1,15 @@
+2015-06-30
+when extending a typed language, use prefix-in for identifiers:
+- that are extended, eg #%datum in ext-stlc.rkt
+ - rename-out the extended implementation of the form
+- or when you want to use racket's version, eg #%app in ext-stlc.rkt
+ - rename-out the prefixed form
+- must except-out the prefixed forms, eg stlc:#%app and stlc:#%datum in ext-stlc
+
2015-06-26
Random thought: Can kinds be "erased"?
- first thought is no, since they appear to be needed for type equality?
+- Solution: add them to body of lambda (eg which represents a forall)
2015-06-26
syntax marks problem:
diff --git a/tapl/tests/rackunit-typechecking.rkt b/tapl/tests/rackunit-typechecking.rkt
@@ -11,7 +11,7 @@
(format
"Expression ~a [loc ~a:~a] has type ~a, expected ~a"
(syntax->datum #'e) (syntax-line #'e) (syntax-column #'e)
- (syntax->datum #'τ) (syntax->datum #'τ-expected))
+ (syntax->datum (get-orig #'τ)) (syntax->datum (get-orig #'τ-expected)))
#'(void)]))
(define-syntax (check-not-type stx)
diff --git a/tapl/tests/run-all-tests.rkt b/tapl/tests/run-all-tests.rkt
@@ -7,6 +7,8 @@
(require "stlc+cons-tests.rkt")
(require "stlc+box-tests.rkt")
+(require "stlc+rec-iso-tests.rkt")
+
(require "stlc+sub-tests.rkt")
(require "stlc+rec+sub-tests.rkt")
diff --git a/tapl/typecheck.rkt b/tapl/typecheck.rkt
@@ -120,7 +120,8 @@
(pattern stx
#:when (stx-pair? #'stx)
#:when (brace? #'stx)
- #:with (τ) #'stx)))
+ #:with (τ:type) #'stx
+ #:with norm #'τ.norm)))
(begin-for-syntax
;; ⊢ : Syntax Type -> Syntax
@@ -178,7 +179,6 @@
(define current-type-eval (make-parameter #f))
- (require inspect-syntax)
;; term expansion
;; expand/df : Syntax -> Syntax
;; Local expands the given syntax object.
@@ -225,10 +225,11 @@
(define-for-syntax (subst τ x e)
(syntax-parse e
[y:id #:when (bound-identifier=? e x) τ]
- [y:id #'y]
[(esub ...)
#:with (esub_subst ...) (stx-map (λ (e1) (subst τ x e1)) #'(esub ...))
- (syntax-track-origin #'(esub_subst ...) e x)]))
+ (syntax-track-origin #'(esub_subst ...) e x)]
+ [_ e]))
+
(define-for-syntax (substs τs xs e)
(stx-fold subst e τs xs))
