Re: Writing a Carriage Return in Unicode

2009-11-28 Thread Aahz
In article mailman.773.1258787463.2873.python-l...@python.org,
Dennis Lee Bieber  wlfr...@ix.netcom.com wrote:
On Thu, 19 Nov 2009 23:22:22 -0800, Scott David Daniels
scott.dani...@acm.org declaimed the following in
gmane.comp.python.general:
 
 If you've actually typed on a physical typewriter, you know that moving
 the carriage back is a distinct operation from rolling the platen
 forward; both operations are accomplished when you push the carriage
 back using the bar, but you know they are distinct.  

   Of course, if you are describing a /real/ /manual/ typewriter, you
would rapidly discover that the sequence is lfcr -- since pushing
the bar would often trigger the line feed before it would slide the
carriage to the right.

Often, but not always; it certainly was possible on most typewriters to
return the carriage without a line feed -- and occasionally desirable for
overstrike.
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Re: Writing a Carriage Return in Unicode

2009-11-22 Thread Steve Howell
On Nov 21, 11:33 pm, Gregory Ewing greg.ew...@canterbury.ac.nz
wrote:
 Steve Howell wrote:
  If you are
  going to couple character sets to their legacy physical
  implementations, you should also have a special extra character to dot
  your i's and cross your t's.

 No, no, no. For that device you need to output a series
 of motion vectors for the scribing point. Plus control
 characters for dip nib and apply blotter, and
 possibly also pluck goose for when the print head
 becomes worn.


Greg, at the first reading of your response, it sounded overly
complicated for me to have to dip nib and  pluck goose every time
I just want to semantically indicate the ninth letter of the English
alphabet, but that's easily solved with a wizard interface, I guess.
Maybe every time I am trying to decide which letter to type in Word,
there could be some kind of animated persona that helps me choose the
character.  There could be a visual icon of an eye that reminds me
of the letter that I am trying to type, and I could configure the
depth to which I dib the nib with some kind of slider interface.  It
actually sounds quite simple and elegant, the more that I think about
it.

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Re: Writing a Carriage Return in Unicode

2009-11-21 Thread Steven D'Aprano
On Thu, 19 Nov 2009 23:22:22 -0800, Scott David Daniels wrote:

 MRAB wrote:
 u'\u240D' isn't a carriage return (that's u'\r') but a symbol (a
 visible CR graphic) for carriage return. Windows programs normally
 expect lines to end with '\r\n'; just use u'\n' in programs and open
 the text files in text mode ('r' or 'w').
 
 rant
 This is the one thing from standards that I believe Microsoft got right
 where others did not.

Oh please, that's historical revisionism -- \r\n wasn't invented by 
Microsoft. Microsoft didn't get it right, they simply copied what CP/M 
did, on account of the original MS-DOS being essentially a clone of CP/M.

And of course the use of \r\n predates computers -- CR+LF (Carriage 
Return + LineFeed) were necessary to instruct the print head on teletype 
printers to move down one line and return to the left. It was a physical 
necessity for the oldest computer operating systems, because the only 
printers available were teletypes.


 The ASCII (American Standard for Information
 Interchange) standard end of line is _both_ carriage return (\r) _and_
 line feed (\n)

I doubt that very much. Do you have a reference for this?

It is true that the predecessor to ANSI (not ASCII), ASA, specified \r\n 
as the line terminator, but ISO specified that both \n and \r\n should be 
accepted.


 I believe in that order.

You believe in that order? But you're not sure?

That's the trouble with \r\n, or \n\r -- it's an arbitrary choice, and 
therefore hard to remember which it is. I've even seen proprietary 
business-to-business software where the developers (apparently) couldn't 
remember which was the standard, so when exporting data to text, you had 
to choose which to use for line breaks.

Of course, being Windows software, they didn't think that you might want 
to transfer the text file to a Unix system, or a Mac, and so didn't offer 
\n or \r alone as line terminators.


 The Unix operating system, in its enthusiasm to make _everything_
 simpler (against Einstein's advice, Everything should be made as simple
 as possible, but not simpler.) decided that end-of-line should be a
 simple line feed and not carriage return line feed.

Why is it too simple to have line breaks be a single character? What is 
the downside of the Unix way? Why is \r\n better? We're not using 
teletypes any more.

Or for that matter, classic Mac OS, which used a single \r as newline.

Likewise for other OSes, such as Commodore, Amiga, Multics...


 Before they made
 that decision, there was debate about the order of cr-lf or lf-cr, or
 inventing a new EOL character ('\037' == '\x1F' was the candidate).

IBM operating systems that use EBCDIC used the NEL (NExt Line) character 
for line breaks, keeping CR and LF for other uses. 

The Unicode standard also specifies that any of the following be 
recognised as line separators or terminators:

LF, CR, CR+LF, NEL, FF (FormFeed, \f), LS (LineSeparator, U+2028) and PS 
(ParagraphSeparator, U+2029).


 If you've actually typed on a physical typewriter, you know that moving
 the carriage back is a distinct operation from rolling the platen
 forward; 

I haven't typed on a physical typewriter for nearly a quarter of a 
century.

If you've typed on a physical typewriter, you'll know that to start a new 
page, you have to roll the platen forward until the page ejects, then 
move the typewriter guide forward to leave space, then feed a new piece 
of paper into the typewriter by hand, then roll the platen again until 
the page is under the guide, then push the guide back down again. That's 
FIVE distinct actions, and if you failed to do them, you would type but 
no letters would appear on the (non-existent) page. Perhaps we should 
specify that text files need a five-character sequence to specify a new 
page too?


 both operations are accomplished when you push the carriage
 back using the bar, but you know they are distinct.  Hell, MIT even had
 line starve character that moved the cursor up (or rolled the platen
 back).
 /rant
 
 Lots of people talk about dos-mode files and windows files as if
 Microsoft got it wrong; it did not -- Unix made up a convenient fiction
 and people went along with it. (And, yes, if Unix had been there first,
 their convention was, in fact, better).

This makes zero sense. If Microsoft got it right, then why is the Unix 
convention convenient and better? Since we're not using teletype 
machines, I would say Microsoft is now using an *inconvenient* fiction.




-- 
Steven
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Re: Writing a Carriage Return in Unicode

2009-11-21 Thread sturlamolden
On 21 Nov, 09:12, Steven D'Aprano st...@remove-this-
cybersource.com.au wrote:

 Oh please, that's historical revisionism -- \r\n wasn't invented by
 Microsoft. Microsoft didn't get it right, they simply copied what CP/M
 did, on account of the original MS-DOS being essentially a clone of CP/M.

Actyually \r\n goes back to early mechanical typewriters with
typebars, such as the Hermes. The operator would hit CR to return the
paper carriage and LF to move down to the next line.






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Re: Writing a Carriage Return in Unicode

2009-11-21 Thread sturlamolden
On 21 Nov, 08:10, Dennis Lee Bieber wlfr...@ix.netcom.com wrote:

         Of course, if you are describing a /real/ /manual/ typewriter, you
 would rapidly discover that the sequence is lfcr -- since pushing
 the bar would often trigger the line feed before it would slide the
 carriage to the right.

         But on a teletype, it would be crlf, and maybe a few rub-outs
 for timing -- as the cr was the slower operation, and would complete
 while the other characters were operated upon...

Ah, yes you are right :-)

The sequence is lfcr on a typewriter.

Which is why the RETURN button often had the symbol

 |
|









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Re: Writing a Carriage Return in Unicode

2009-11-21 Thread Steve Howell
On Nov 21, 12:12 am, Steven D'Aprano st...@remove-this-
cybersource.com.au wrote:
 On Thu, 19 Nov 2009 23:22:22 -0800, Scott David Daniels wrote:

  If you've actually typed on a physical typewriter, you know that moving
  the carriage back is a distinct operation from rolling the platen
  forward;

 I haven't typed on a physical typewriter for nearly a quarter of a
 century.

 If you've typed on a physical typewriter, you'll know that to start a new
 page, you have to roll the platen forward until the page ejects, then
 move the typewriter guide forward to leave space, then feed a new piece
 of paper into the typewriter by hand, then roll the platen again until
 the page is under the guide, then push the guide back down again. That's
 FIVE distinct actions, and if you failed to do them, you would type but
 no letters would appear on the (non-existent) page. Perhaps we should
 specify that text files need a five-character sequence to specify a new
 page too?

  both operations are accomplished when you push the carriage
  back using the bar, but you know they are distinct.  Hell, MIT even had
  line starve character that moved the cursor up (or rolled the platen
  back).
  /rant

  Lots of people talk about dos-mode files and windows files as if
  Microsoft got it wrong; it did not -- Unix made up a convenient fiction
  and people went along with it. (And, yes, if Unix had been there first,
  their convention was, in fact, better).

 This makes zero sense. If Microsoft got it right, then why is the Unix
 convention convenient and better? Since we're not using teletype
 machines, I would say Microsoft is now using an *inconvenient* fiction.

 --
 Steven

It's been a long time since I have typed on a physical typewriter as
well, but I still vaguely remember all the crazy things I had to do to
get the tab key to produce a predictable indentation on the paper
output.

I agree with Steven that \r\n is completely insane.  If you are
going to couple character sets to their legacy physical
implementations, you should also have a special extra character to dot
your i's and cross your t's.  Apparently neither Unix or Microsoft got
that right.  I mean, think about it, dotting the i is a distinct
operation from creating the undotted i. ;)

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Re: Writing a Carriage Return in Unicode

2009-11-21 Thread Gregory Ewing

Steve Howell wrote:

If you are
going to couple character sets to their legacy physical
implementations, you should also have a special extra character to dot
your i's and cross your t's.


No, no, no. For that device you need to output a series
of motion vectors for the scribing point. Plus control
characters for dip nib and apply blotter, and
possibly also pluck goose for when the print head
becomes worn.

--
Greg
--
http://mail.python.org/mailman/listinfo/python-list


Re: Writing a Carriage Return in Unicode

2009-11-20 Thread Scott David Daniels

MRAB wrote:

u'\u240D' isn't a carriage return (that's u'\r') but a symbol (a visible
CR graphic) for carriage return. Windows programs normally expect
lines to end with '\r\n'; just use u'\n' in programs and open the text
files in text mode ('r' or 'w').


rant
This is the one thing from standards that I believe Microsoft got right
where others did not.  The ASCII (American Standard for Information
Interchange) standard end of line is _both_ carriage return (\r) _and_
line feed (\n) -- I believe in that order.

The Unix operating system, in its enthusiasm to make _everything_
simpler (against Einstein's advice, Everything should be made as simple
as possible, but not simpler.) decided that end-of-line should be a
simple line feed and not carriage return line feed.  Before they made
that decision, there was debate about the order of cr-lf or lf-cr, or
inventing a new EOL character ('\037' == '\x1F' was the candidate).

If you've actually typed on a physical typewriter, you know that moving
the carriage back is a distinct operation from rolling the platen
forward; both operations are accomplished when you push the carriage
back using the bar, but you know they are distinct.  Hell, MIT even had
line starve character that moved the cursor up (or rolled the platen
back).
/rant

Lots of people talk about dos-mode files and windows files as if
Microsoft got it wrong; it did not -- Unix made up a convenient fiction
and people went along with it. (And, yes, if Unix had been there first,
their convention was, in fact, better).

So, sorry for venting, but I have bee wanting to say this in public
for years.

--Scott David Daniels
scott.dani...@acm.org
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Re: Writing a Carriage Return in Unicode

2009-11-20 Thread sturlamolden
On 19 Nov, 01:14, Doug caldwelli...@verizon.net wrote:

 Thanks for your help!!

A carriage return in unicode is

   u\r

how this is written as bytes is dependent on the encoder.

Don't try to outsmart the UTF-8 codec, it knows how to translate \r
to UTF-8.


Sturla Molden
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Re: Writing a Carriage Return in Unicode

2009-11-19 Thread Doug

Hi! Thanks for clearing this up!!
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Writing a Carriage Return in Unicode

2009-11-18 Thread Doug

Hi!

I am trying to write a UTF-8 file of UNICODE strings with a carriage
return at the end of each line (code below).

filOpen = codecs.open(c:\\temp\\unicode.txt,'w','utf-8')

str1 = u'This is a test.'
str2 = u'This is the second line.'
str3 = u'This is the third line.'

strCR = u\u240D

filOpen.write(str1 + strCR)
filOpen.write(str2 + strCR)
filOpen.write(str3 + strCR)

filOpen.close()

The output looks like
This is a test.␍This is the second line.␍This is the third
line.␍ when opened in Wordpad as a UNICODE file.

Thanks for your help!!
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Re: Writing a Carriage Return in Unicode

2009-11-18 Thread MRAB

Doug wrote:

Hi!

I am trying to write a UTF-8 file of UNICODE strings with a carriage
return at the end of each line (code below).

filOpen = codecs.open(c:\\temp\\unicode.txt,'w','utf-8')

str1 = u'This is a test.'
str2 = u'This is the second line.'
str3 = u'This is the third line.'

strCR = u\u240D

filOpen.write(str1 + strCR)
filOpen.write(str2 + strCR)
filOpen.write(str3 + strCR)

filOpen.close()

The output looks like
This is a test.�This is the second line.�This is the third
line.� when opened in Wordpad as a UNICODE file.

Thanks for your help!!


u'\u240D' isn't a carriage return (that's u'\r') but a symbol (a visible
CR graphic) for carriage return. Windows programs normally expect
lines to end with '\r\n'; just use u'\n' in programs and open the text
files in text mode ('r' or 'w').

Some Windows programs won't recognise UTF-8 text as UTF-8 in files
unless they start with a BOM; this will be handled automatically in
Python if you specify the encoding as 'utf-8-sig'.
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