Re: Using append to create a list from a line of text

[Pascal J. Bourguignon]

Barry Margolin <barmar@alum.mit.edu> writes:

> In article <87ip3m6vyj.fsf@kuiper.lan.informatimago.com>,
>  "Pascal J. Bourguignon" <pjb@informatimago.com> wrote:
>
>> acomber <deedexy@gmail.com> writes:
>> 
>> > I want to create a list of words from a line of text delimitted by tabs. I
>> > want to basically split the line into atoms, split by tab.
>> >
>> > The code below is sort of pseudocode but is this the best approach to do
>> > this type of thing?
>> >
>> > Here is my first attempt:-
>> >
>> > (defun get-hdr()
>> >     ;obviously point must be positioned on correct line
>> >     (let (mylist)
>> >       while(not (end-of-line)
>> >          while(re-search-forward ("[A-Za-z]+[^\t\n]" nil t)
>> >            append (match-string 1) mylist      
>> >          )
>> >       )
>> >    )
>> > )
>> 
>> Nice, but it's not formatted correctly.  I'd avise you to use
>> paredit-mode.
>> 
>> Adding and removing newlines where one should, and letting emacs indent
>> the sexp, we get this text:
>> 
>> 
>>     (defun get-hdr()
>>       ;; obviously point must be positioned on correct line
>>       (let (mylist)
>>         while
>>         (not (end-of-line)
>>              while
>>              (re-search-forward ("[A-Za-z]+[^\t\n]" nil t)
>>                                 append
>>                                 (match-string 1)
>>                                 mylist))))
>> 
>> Now, two obvious things:
>> 
>> 1- undefined variable named `while'.  Where does that variable come
>>    from?
>> 
>> 2- the function `not' is passed three arguments, when it expects only
>>    one!
>
> I think you missed that he said this was pseudo-code, not valid Lisp 
> code.

Indeed, I missed it.  But also, if you write your pseudo code as a
possibly valid lisp form, you can easily make it executable:

http://groups.google.com/group/comp.lang.lisp/msg/a827235ce7466a92

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.