Leonardo Varuzza  <varuzza@gmail.com> wrote:
+---------------
| If I want to print a list with the values separated by commas I can
| use this handy format recipe:
| 
| (format t "~{~a~^,~}" '(1 2 3))
| 
| But how I can reproduce this for a Tab Delimited printing?
| Or, how to embed a tab character in a lisp string?
+---------------

Several ways:

1. Tabs aren't "special" in CL strings; simply insert it:

        ; A #\Tab is here ---v
        > (format t "~&~{~a~^	~}" '(1 2 3))
        1	2	3
        NIL
        > 

2. If you don't need "real" tabs, just tabular spacing,
   then you can use the "~T" FORMAT control:

        > (format t "~&~{~a~^~0,8t~}" '(1 2 3))
        1       2       3
        NIL
        > 

3. If you need real #\Tab characters but don't want to have
   obscure bugs because of unexpected whitespace reformatting
   [e.g., some editors "helpfully" silently replace spaces
   by tabs or vice-versa under certain random conditions],
   then you can do something like this:

        > (let ((fmt (format nil "~~&~~{~~a~~^~c~~}" #\Tab)))
            (format t fmt '(1 2 3)))
        1	2	3
        NIL
        > 


-Rob

p.s. I have tried to have the only tabs in this reply be
only the five instances that *should* be there in the example
codes & outputs above, but my editor and/or the netnews system
may tweak the result between me & thee. If so, then my most
abject apologies in advance...

-----
Rob Warnock                     <rpw3@rpw3.org>
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San Mateo, CA 94403             (650)572-2607