Why don't people like lisp?

[Jock Cooper]

Pascal Costanza <costanza at web.de> writes:
> Andrew Dalke wrote:
> 
> (with-open-file (f "...")
>    ...
>    (read f)
>    ...)
> 
> ...is much clearer than...
> 
> try:
>     f=open('...')
>     ...
>     f.read()
>     ...
> finally:
>     f.close()
> 
> Why do I need to say "finally" here? Why should I even care about
> calling close? What does this have to do with the problem I am trying
> to solve? Do you really think it does not distract from the problem
> when you first encounter that code and try to see the forest from the
> trees?
>snip

Can you implement with-open-file as a function?  If you could how would
it compare to the macro version?  It would look something like:

(defun with-open-file (the-func &rest open-args)
  (let ((stream (apply #'open open-args)))
        (unwind-protect 
          (funcall the-func stream)
          (close stream))))

(defun my-func (stream)
  ... operate on stream...
)

(defun do-stuff ()
   (with-open-file #'my-func "somefile" :direction :input))

One of the important differences is that MY-FUNC is lexically isolated
from the environment where WITH-OPEN-FILE appears.  The macro version
does not suffer this; and it is often convenient for the code block
in the WITH-OPEN-FILE to access that environment.