Python syntax in Lisp and Scheme

[Marco Antoniotti]

David Eppstein wrote:

> In article <blsbpf$i9n$1 at newsreader2.netcologne.de>,
>  Pascal Costanza <costanza at web.de> wrote:
> 
> 
>>I don't know a lot about Python, so here is a question. Is something 
>>along the following lines possible in Python?
>>
>>(with-collectors (collect-pos collect-neg)
>>   (do-file-lines (l some-file-name)
>>     (if (some-property l)
>>       (collect-pos l)
>>       (collect-neg l))))
>>
>>
>>I actually needed something like this in some of my code...
> 
> 
> Not using simple generators afaik.  The easiest way would probably be to 
> append into two lists:
> 
>     collect_pos = []
>     collect_neg = []
>     for l in some_file_name:
                ^^^^^^^^^^^^^^

Please be precise.  You are missing the definition of 'some_file_name'. 
  The CL macro can hide the fact that you are passing the iterator 
either a string or a structured pathname or an iterator instance.  In 
Python you have to include the definition of 'some_file_name'.

In CL the following will work (assuming that the DO-FILE-LINES CL macro 
is written correctly)

	(let ((some-file-name "/tmp/foo.txt"))
	   (with-collectors (collect-pos collect-neg)
	      (do-file-lines (l some-file-name)
	         (if (some-property l)
	            (collect-pos l)
	            (collect-neg l)))))

In Pyhton

	some_file_name = '/tmp/foo.txt'
	collect_pos = []
	collect_pos = []
	for l in some_file_name:

will happily bind 'l' to the characters in '/tmp/foo.txt'.


Cheers
--
Marco