[racket] ok what's wrong there 'syntax-rule' evaluating its operand (??)

Here is a macro that is working, .. at least in the context it is being
used:

  (define-syntax (with-tables stx)
    (let*(
           [datum  (syntax->datum stx)]
           [stem   (cadr datum)]
           [body   (cddr datum)]
           )
      (datum->syntax stx
        (append
          `(let(
                 [table-publication (string-append ,stem "_publication")]
                 [table-author (string-append ,stem "_author")]
                 [table-bridge-publication-author (string-append ,stem
"_bridge_publication_author")]
                 [table-unique-counters (string-append ,stem
"_unique_counters")]
                 ))
          body
          )

racket@> (with-tables "x" (displayln table-publication) table-author)
x_publication
"x_author"



This same functionality as a syntax rule:

 (define-syntax with-tables
    (syntax-rules ()
      [(with-tables stem body ...)
        (let(
              [table-publication (string-append stem "_publication")]
              [table-author (string-append stem "_author")]
              [table-bridge-publication-author (string-append stem
"_bridge_publication_author")]
              [table-unique-counters (string-append stem
"_unique_counters")]
              )
          body ...
          )
        ]
      ))

   #|
    racket@> (with-tables "x" table-author)
    reference to undefined identifier: table-author
    stdin::6353: table-author
     === context ===
    /usr/share/racket/collects/racket/private/misc.rkt:87:7
   |#



Fails with a undefined identifier, but to do that it would have to evaluate
the argument.   Ok, so what did I do wrong here?

..not surprisingly, same result with define-syntax-rule ..

 (define-syntax-rule (with-tables stem body ...)
      (let(
            [table-publication (string-append stem "_publication")]
            [table-author (string-append stem "_author")]
            [table-bridge-publication-author (string-append stem
"_bridge_publication_author")]
            [table-unique-counters (string-append stem "_unique_counters")]
            )
        body ...
        ))

  #|
    racket@> (with-tables "x" table-author)
    reference to undefined identifier: table-author
    stdin::6353: table-author
     === context ===
    /usr/share/racket/collects/racket/private/misc.rkt:87:7
  |#


-Thomas
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