Hi everybody, I'm proposing to make colons optional. Let me call this feature Colonless Python. To show what it is like without colons, here are some examples adapted from the official tutorial. ---------- sample code ----------- if statement ============ if x < 0 x = 0 print 'Negative changed to zero' elif x == 0 print 'Zero' elif x == 1 print 'Single' else print 'More' for statement ============= for x in a print x, len(x) while statement =============== # Fibonacci series: # the sum of two elements defines the next a, b = 0, 1 while b < 10 print b a, b = b, a+b function definition ================== def fib(n) # write Fibonacci series up to n """Print a Fibonacci series up to n.""" a, b = 0, 1 while b < n print b, a, b = b, a+b class definition ================ class MyClass """A simple example class""" i = 12345 def f(self) return 'hello world' ------------- end -------------- Please note that like semicolons, one can still write one-liners with colons like if x > 0: y = z; x = y or for each in range(10): x += each; x -= each**2 I'm proposing this due to several reasons, namely - I noticed a strong tendency to forget colons by new users of Python in a second-year computer science undergraduate course. The students seemed not getting used to colons even near the end of the course. I guess it is probably because they learn Java and C first, both of which do not have colons. What other languages do you know that require colons? Colons seem to be a trap for new Python users from other languages. - We already have indentation to visually separate different levels of code. Why bother with those extra colons at all? They should be optional just like semicolons are optional (and discouraged) for line breaks. I doubt we will ever lose much, if any, by omitting colons. - I find colons pretty annoying. They interrupt mental flows of thinking. I have to do a mental break at the end of conditionals, loops, function and class definitions, and then a physical break to type "SHIFT+;" to get the colons before I continue on the subsequent lines. It's not really a big issue, but it is annoying. What do you think? Specifically, may I ask your feedback on the following issues? - Do you find yourself sometimes forget to type them and the interpreter complains? - Are the above pieces of code less readable due to lack of colons? - What problems do you think will occur if colons are made optional? PS. I had some preliminary discussion in the comments on one of Guido's blog posts about Python's history. If you are interested, you can check out this link http://python-history.blogspot.com/2009/01/pythons-design-philosophy.html#co... Best, Rio