> Lexical variables and closures don't need each other,

a "closure" over a global variable is commonly known as a function using a global variable ...

IMHO that's far too trivial to be called a closure. :-p

Not sure why you are doing this

    arg = arg # make arg a lexical variable

arg should be a lexical var right away.

you might want to compare this, a is a lexical and clos a generated closure

>>> def test(a):
...   def clos():
...     return a
...   return clos
... 
>>> x=test(1)
>>> y=test(22)
>>> x()
1
>>> y()
22

[download]

This is pretty much a demonstration of lexical scope, you will only deal with dynamic scope when using global vars or accessing class attributes.*

Update

*) Well if functions call each other and close over the same lexical one might call this a dynamic scope too.

For instance a recursive closure.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

In reply to Re^6:Evolution of python by LanX
in thread Evolution of python by betmatt

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.