added scheme/base import and re-tabified

svn: r14029

collects/trace/stacktrace.ss

@@ -1,8 +1,8 @@
-
-(module stacktrace scheme/base
+#lang scheme/base
 (require mzlib/unit
          syntax/kerncase
-           syntax/stx)
+         syntax/stx
+         (for-syntax scheme/base))
 
 (provide stacktrace@ stacktrace^ stacktrace-imports^)
 
@@ -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)))