Adding a new statement to Python (eli.thegreenplace.net)

http://wiki.tcl.tk/917

http://www.yosefk.com/blog/my-history-with-forth-stack-machi...

my mind was immediately blown away by the following passage right at the top of system.fth, the part of pForth implemented in Forth on top of the C interpreter:

    : (   41 word drop ; immediate
    ( That was the definition for the comment word. )
    ( Now we can add comments to what we are doing! )

    (defmacro unless [expr & body] `(if ~expr nil (do ~@body)))

Macro in Lisp are essentially functions taking code as argument and returning code, but they are executed at compile-time.

Edit: replaced with the correct version, sorry for the error.

  unless := method(call evalArgAt(0) ifFalse(call evalArgAt(1)))

  unless(1 == 2, writeln("Tis false"))

Here's the second section:

A language-advocacy digression

------------------------------

This article doesn’t attempt to suggest the addition of an until statement to Python. Although I think such a statement would make some code clearer, and this article displays how easy it is to add, I completely respect Python’s philosophy of minimalism. All I’m trying to do here, really, is gain some insight into the inner workings of Python.