Re: Linux.com: Python 3 makes a big break

[Jean-Paul Calderone]

On Sat, 18 Oct 2008 15:30:23 -0400, Terry Reedy <tj*****@udel.eduwrote:

>http://www.linux.com/feature/150399
Interesting article with one minor incompleteness.
"For instance, the print statement got turned into a print function; you
must now put parentheses around what you want to print to the screen. The
change allows developers to work with print in a more flexible and uniform
way. If someone needs to replace the print function with some other action,
it can be done with a universal search and replace, rather than rewriting
each print statement by hand."

Even easier, print as a function can be replaced simply by defining a new
version with the same name. No search/replace is needed. And reversion to
the built-in only requires commenting out the replacement.

Perhaps it also omitted the fact that nothing prevents you from defining a
function to write things to stdout (or elsewhere) in Python 2.5, making the
Python 3.x change largely a non-feature. ;)

Jean-Paul

[Kay Schluehr]

On 18 Okt., 22:01, Jean-Paul Calderone <[e-mail]:

Perhaps it also omitted the fact that nothing prevents you from defining a
function to write things to stdout (or elsewhere) in Python 2.5, making the
Python 3.x change largely a non-feature. ;)

Jean-Paul

Even more. If someone had solved the hard problem of finding a less
cumbersome way of writing sys.stdout.write(...) the request for
multiline lambdas ( multi expression lambdas actually ) could have
been decreased about 75-80%.

[Lawrence D'Oliveiro]

In message
<de**********************************@g61g2000hsf. googlegroups.com>, Kay
Schluehr wrote:

If someone had solved the hard problem of finding a less
cumbersome way of writing sys.stdout.write(...) ...

I don't see what the big deal is. I regularly write things like

sys.stdout.write \
(
"<INPUT TYPE=\"RADIO\" NAME=\"%(name)s\""
" ID=\"%(name)s[%(value)s]\" VALUE=\"%(value)s\"%(checked)s>"
"<LABEL FOR=\"%(name)s[%(value)s]\">%(title)s</LABEL>\n"
# using LABEL lets user click on text to select button
%
{
"name" : EscapeHTML(Name),
"value" : EscapeHTML(Value),
"title" : Title,
"checked" : ("", " CHECKED")[Checked],
}
)

[Steven D'Aprano]

On Sat, 18 Oct 2008 21:34:13 -0700, Kay Schluehr wrote:

On 18 Okt., 22:01, Jean-Paul Calderone <[e-mail]:

>Perhaps it also omitted the fact that nothing prevents you from
defining a function to write things to stdout (or elsewhere) in Python
2.5, making the Python 3.x change largely a non-feature. ;)

Jean-Paul

Even more. If someone had solved the hard problem of finding a less
cumbersome way of writing sys.stdout.write(...) the request for
multiline lambdas ( multi expression lambdas actually ) could have been
decreased about 75-80%.

Er, am I missing something? How about this?

import sys
pr = sys.stdout.write

pr('Is this less cumbersome enough for you?')

But of course, that doesn't really help you avoid multi-expression
lambdas, unless you want to write obfuscated code:

def foo(x):
y = x+1
print y
return y

is roughly, but inefficiently, equivalent to:

lambda x: sys.stdout.write(x+1) or x+1

But that's cumbersome and obfuscated, and not scalable at all.

--
Steven

[Aahz]

In article <gd**********@lust.ihug.co.nz>,
Lawrence D'Oliveiro <ld*@geek-central.gen.new_zealandwrote:

>In message
<de**********************************@g61g2000hsf .googlegroups.com>, Kay
Schluehr wrote:

>>
If someone had solved the hard problem of finding a less
cumbersome way of writing sys.stdout.write(...) ...

I don't see what the big deal is. I regularly write things like

sys.stdout.write \
(
"<INPUT TYPE=\"RADIO\" NAME=\"%(name)s\""
" ID=\"%(name)s[%(value)s]\" VALUE=\"%(value)s\"%(checked)s>"
"<LABEL FOR=\"%(name)s[%(value)s]\">%(title)s</LABEL>\n"
# using LABEL lets user click on text to select button
%
{
"name" : EscapeHTML(Name),
"value" : EscapeHTML(Value),
"title" : Title,
"checked" : ("", " CHECKED")[Checked],
}
)

Why are you using a backslash?
--
Aahz (aa**@pythoncraft.com) <* http://www.pythoncraft.com/

import antigravity

[D'Arcy J.M. Cain]

On 19 Oct 2008 07:44:52 -0700
aa**@pythoncraft.com (Aahz) wrote:

sys.stdout.write \
(

Why are you using a backslash?

Because he hasn't opened the paren yet. He could have put the open
paren on the same line as the write obviating the need for the
backslash but then his open/close parens wouldn't line up. It just a
matter of style.

--
D'Arcy J.M. Cain <da***@druid.net | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
[phone] (DoD#0082) (eNTP) | what's for dinner.

[Aahz]

In article <ma**************************************@python.o rg>,
D'Arcy J.M. Cain <da***@druid.netwrote:

>On 19 Oct 2008 07:44:52 -0700
aa**@pythoncraft.com (Aahz) wrote:

>> sys.stdout.write \
(

Why are you using a backslash?

Because he hasn't opened the paren yet. He could have put the open
paren on the same line as the write obviating the need for the
backslash but then his open/close parens wouldn't line up. It just a
matter of style.

Well, no, it's not *just* a matter of style. I'm strongly opposed to
backslashes because they break when you get whitespace after them. (And
note carefully that I said "when" and not "if".)
--
Aahz (aa**@pythoncraft.com) <* http://www.pythoncraft.com/

import antigravity

[Lawrence D'Oliveiro]

In message <vZ******************************@earthlink.com> , Dennis Lee
Bieber wrote:

There is also the matter that the original material is using " on
each line to delimit the string, and then \" within the line to escape
the desired output "s, rather than either using ' for the string and
bare " for the output characters ...

I prefer using double-quotes universally. One less decision to make.

... or triple quoting the whole block...

Not a good idea.

[Lawrence D'Oliveiro]

In message <gd**********@panix3.panix.com>, Aahz wrote:

I'm strongly opposed to backslashes because they break when you get
whitespace after them.

1) I've never had that problem.
2) Even if I did, it would report a syntax error, it's not going to fail
silently and introduce any run-time bugs, is it?