"Cameron Laird" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> In article <[EMAIL PROTECTED]>,
> <[EMAIL PROTECTED]> wrote:
>>Hi,
>>
>>I have a file that contains a "tcl" list stored as a string. The list
>>members are
>>sql commands ex:
>> { begin { select * from foo
>> where baz='whatever'}
>> {select * from gooble } end
>> { insert into bar values('Tom', 25) } }
>>
>>I would like to parse the tcl list into a python list...
>>
>>Any suggestions ( I am running Tkinter...)
> .
> .
> .
> No correct solution's going to be as elegant as I suspect you imagine.
> Here's an example of what's required:
>
> # If you try anything you suspect is simpler, you're going to have to
> # teach Python about Tcl treatment of whitespace, or teach Tcl how
> # Python quotes, or ...
>
> import Tkinter
> tcl_list = """{ begin { select * from foo
> where baz='whatever'}
> {select * from gooble } end
> { insert into bar values('Tom', 25) } }"""
>
> # Collect the Python list here.
> result = []
> # Create a single Tcl interpretive context for all the work.
> tk_instance = Tkinter.Tk().tk.eval
> # Everything Tcl returns is a string; make this value an integer.
> tcl_list_length = int(tk_instance(
> "set tcl_list %s; llength $tcl_list" % tcl_list))
>
> # With all the set-up done, simply loop over the elements.
> for counter in range(tcl_list_length):
> # Ask Tcl for each successive list item.
> result.append(tk_instance("lindex $tcl_list %d" % counter))
>
> print result
>
> The output is
> ['begin', " select * from foo\n where baz='whatever'",
> 'select * from gooble ', 'end', " insert into bar values('Tom', 25) "]
Elegant-shmelegant, looks like it gets the job done, and neatly too. I had
no idea that you can invoke Tcl so easily from Python.
Why is your indentation so weird though? The comments actually make your
solution harder to read. If I may be so forward as to edit for readability
(I think a list comprehension to build the actual list is easier to follow
than the for loop with the strangely-indented comments):
# Create a single Tcl interpretive context for all the work.
tk_instance = Tkinter.Tk().tk.eval
# define list in Tcl context, and extract number of elements
tk_instance("set tcl_list %s" % tcl_list)
numItems = int(tk_instance("llength $tcl_list"))
# build Python list indexing by each item
result = [ tk_instance("lindex $tcl_list %d" % i)
for i in range(numItems)]
-- Paul
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