Robert Uhl wrote:
> o Macros
>
> As mentioned above, macros can make one's life significantly nicer. I
> use Python a lot (it's currently a better choice than Lisp for many of
> the problems I face), and I find myself missing macros all the time.
> The ability to take some frequently-used idiom and wrap it up in a macro
> is wonderful. E.g. a common idiom in Python is:
>
> file = open(path, 'r')
> for line in file.readlines():
> foo(line)
> bar(line)
> baz(line)
>
> Even this isn't much nicer:
>
> for line in open(path, 'r').readlines():
> foo(line)
> bar(line)
> baz(line)
>
> Wouldn't it be nice to have a macro with-open-file?
>
> filefor line in path:
> foo(line)
> bar(line)
> baz(line)
>
You probably need to refresh your Python skills if you want to be more
productive in it. Files have been iterable for the last couple of years
(since 2.1-2.2, don't remember).
for line in open(path):
foo(line)
bar(line)
baz(line)
You can also iterate through the lines of more than one files using the
fileinput module (http://docs.python.org/lib/module-fileinput.html):
import fileinput
# iterate over the lines of the files passed as command line
# arguments (sys.argv[1:]) or sys.stdin for no arguments
for line in fileinput.input():
foo(line)
I'm sure there should be more convincing examples for macros, but
neither this nor the 'unless' syntax sugar cuts it.
George
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