added scheme/base import and re-tabified

svn: r14029

collects/trace/stacktrace.ss

@@ -1,20 +1,20 @@
-
-(module stacktrace scheme/base
-  (require mzlib/unit
+#lang scheme/base
+(require mzlib/unit
          syntax/kerncase
-           syntax/stx)
+         syntax/stx
+         (for-syntax scheme/base))
 
-  (provide stacktrace@ stacktrace^ stacktrace-imports^)
+(provide stacktrace@ stacktrace^ stacktrace-imports^)
 
-  (define-signature stacktrace-imports^ (calltrace-key print-call-trace))
-  (define-signature stacktrace^ (annotate))
+(define-signature stacktrace-imports^ (calltrace-key print-call-trace))
+(define-signature stacktrace^ (annotate))
 
-  (define o (current-output-port))
-  (define (oprintf . args) (apply fprintf o args))
+(define o (current-output-port))
+(define (oprintf . args) (apply fprintf o args))
 
-  (define-struct stx-protector (stx))
+(define-struct stx-protector (stx))
 
-  (define-unit stacktrace@
+(define-unit stacktrace@
   (import stacktrace-imports^)
   (export stacktrace^)
   
@@ -153,11 +153,10 @@
          [(#%top . var)
           stx]
          [else
-              (if trans?-expr
+          (error 'expr-iterator "unknown expression (phase ~s): ~s ~s" 
+                 trans?-expr
                  stx
-                  (error 'expr-iterator "unknown expression: ~s ~s" 
-                         stx
-                         (syntax->datum stx)))])
+                 (syntax->datum stx))])
        stx
        insp
        #f)))
@@ -175,4 +174,4 @@
          (loop #'rest (cons #'var so-far))])))
   
   
-      (define (annotate x) (top-level-expr-iterator x))))
+  (define (annotate x) (top-level-expr-iterator x)))