On 5-Feb-09, at 6:05 PM, Steven D'Aprano wrote:
A switch/case statement is equivalent to a series of
statements, so it would be inconsistent to require colons in a
switch but not in if...elif.
Python does not have switch/case statements. Java/C does not have
significant indentation. Do you mean Java/C should also use colons
after if's, given that they use colons after case's?
My point was that both languages (Pascal and Python)
use colons in a
way which is very familiar and standard to the English language,
albeit different usages in the two languages. If newbies to either
language find colons confusing, that's indicative of the general
decline of educational standards. If people whose first language is
not English have trouble with colons, then I sympathize, but then so
much of Python is based on English-like constructs that colons will
be the least of their problem.
I did not notice anybody complained about colons because their first
language is not English. Why bring it up?
Yes, colons are natural in English. It is even more natural in English
to end sentences with periods. Do you want to do that in Python?
Erlang does that, and it's ugly.
you cannot simply copy what we do in English to programming languages
after all we do not carriage-return and indent our sentences like Python
Yes I agree
with you that many people like colons. What bothers me
is that some people dislike them, but not given the choice to avoid
them. We don't like semicolons in Python, but what would stop a
hard-core C users to end every statement with a semicolon?
Peer pressure. Everybody would laugh at their code and think they're
Same for semicolons, I would laugh and think it's foolish to type
colons when we have to carriage-return and indent right after them
Flexibility of punctuation hurts computer languages, not helps.
So we should really forbid x, y = m, n and instead force (x, y) = (m, n)
trailing colons OPTIONAL, we can probably have the chance
to field test. If people really think colons improve readability
that much, they can still use them, just like we feel semicolons
are line noise and void them if possible, even though we CAN use
them. I don't think we will ever lose anything to make colons
Of course we do. It makes the language bigger and more complex. The
parser has to be more complex. Who is going to write that, maintain
Do you really think making colons optional makes Python bigger and
more complex? One less thing to worry about in addition to indentation
makes the parser more complex?
Every time you write a def block you have to decide
"colon or not?".
Most people will standardize on one or the other, and the decision
will go away, but they will still need to read other people's code,
and then colon-haters will be unhappy, because they have to read
other people's code containing colons, while colon-likers will be
unhappy, because they have to read other people's code missing colons.
Optional colons are the worst of both worlds, because it makes
"Every time you start a new line you have to decide "semicolon or
not?". Most people will standardize on one or the other, and the
decision will go away, but they will still need to read other people's
code, and then semicolon-haters will be unhappy, because they have to
read other people's code containing semicolons, while semicolons- likers will be unhappy, because they have to read other people's code
Optional semicolons are the worst of both worlds, because it makes
everybody unhappy. "
Does that happen? I would argue if colons are made optional, in the
long run we will treat them like dinosaurs. If you disagree, think
this: try convincing hard-core C users that they should really get rid