anchor.diff:      (fset:seq (make-string-fragment \"foo\") (make-string-fragment \"bar\" :literal t))
   
   Use word boundaries responsibly.  Check with `*split-fields*' before
  -you insert them into your return value."))
  +you insert them into your return value.
  +
  +If the expansion process involves running a command, you may return an
  +`exit-info' or an `fset:seq' of `exit-info' as the second return
  +value."))
   
   (defmethod expand ((thing string))
     (fset:seq (make-string-fragment thing :literal t)))
  
positive.code:   (:import-from :shcl/core/posix #:syscall-error)
    (:import-from :shcl/core/posix-types #:dirent #:d-name)
    (:import-from :shcl/core/fd-table #:with-dir-ptr-for-fd #:openat-retained #:fd-release)
    (:export
     #:expansion-for-words #:set-alias #:unalias #:expand #:make-string-fragment
     #:word-boundary #:*split-fields* #:split))
  
negative.code: 
      (unless expand-pathname
        (return-from expansion-for-words
          (values (fset:image #'concat-fragments result)
                  exit-infos)))
  
      (let ((pathname-expansion-results (fset:empty-seq)))
        (fset:do-seq (fragments result)
          (fset:appendf pathname-expansion-results (expand-pathname fragments)))
        (values pathname-expansion-results
                exit-infos))))
  
  (defstruct wild-path
    "This struct represents a path which may have components which
  