Merged in make-var-like-trans (pull request #1)

add version of make-variable-like-transformer

.gitignore

@@ -0,0 +1,3 @@
+compiled/
+doc/
+*~

tapl/stlc+lit.rkt

@@ -29,13 +29,8 @@
          #;(define-syntax op/tc (make-rename-transformer (assign-type #'op #'τ)))
          ; rename transformer doesnt seem to expand at the right time
          ; - op still has no type in #%app
-         (define-syntax (op/tc stx)
-           (syntax-parse stx
-             [f:id (⊢ #,(syntax/loc stx op) : τ)] ; HO case
-             [(o . rst)
-              #:with app (datum->syntax #'o '#%app)
-              #:with opp (format-id #'o "~a" #'op)
-              (syntax/loc stx (app opp . rst))])))]))
+         (define-syntax op/tc
+           (make-variable-like-transformer (assign-type #'op #'τ))))]))
 
 (define-primop + : (→ Int Int Int))
 

tapl/stx-utils.rkt

@@ -47,4 +47,19 @@
 
 (define (stx-append stx1 stx2)
   (append (if (syntax? stx1) (syntax->list stx1) stx1)
-          (if (syntax? stx2) (syntax->list stx2) stx2)))
+          (if (syntax? stx2) (syntax->list stx2) stx2)))
+
+;; based on make-variable-like-transformer from syntax/transformer,
+;; but using (#%app id ...) instead of ((#%expression id) ...)
+(define (make-variable-like-transformer ref-stx)
+  (unless (syntax? ref-stx)
+    (raise-type-error 'make-variable-like-transformer "syntax?" ref-stx))
+  (lambda (stx)
+    (syntax-case stx ()
+      [id
+       (identifier? #'id)
+       ref-stx]
+      [(id . args)
+       (let ([stx* (list* '#%app #'id (cdr (syntax-e stx)))])
+         (datum->syntax stx stx* stx))])))
+