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Trigraphs

 
 
Richard Bos
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      11-09-2005
http://www.velocityreviews.com/forums/(E-Mail Removed) (Richard Tobin) wrote:

> In article <(E-Mail Removed)>,
> Mark McIntyre <(E-Mail Removed)> wrote:
>
> >>US keyboards aren't the problem. What characters are missing from your
> >>Mac's US keyboard?

> >
> >There's no hash key.....

>
> Really? I thought that was just on UK keyboards. What do you have
> on shift-3?


Mine has a hash. I've no idea what Mark is using, but it's not a normal
Mac US keyboard.

Richard
 
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Michael Wojcik
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      11-09-2005

In article <436fe91e$0$11078$(E-Mail Removed)4all.nl>, Skarmander <(E-Mail Removed)> writes:
>
> EBCDIC has many funky versions, but do you actually know ones that do
> not have the characters of the C trigraph set (# [ \ ] ^ { | } ~)? (This
> is a genuine question, not an attempt at being snarky.)


Yes. The standard US EBCDIC "coded graphic character set" (which
consists of character set 600 encoded using code page 500) doesn't
have the square brackets, for example, or the tilde. And those
characters don't appear on the standard US keyboards for some IBM
terminal types for systems that have C implementations available,
such as the 5250.

00640-00500 also seems to be missing the number sign, though since
that does appear in most older IBM character sets (eg A, AE, 930, and
USS), it's probably widely available on EBCDIC systems. I don't
recall offhand if it appears on the US 5250 keyboard.

Hmm. I've now put my reference away, but I think the "broken"
vertical bar character is missing from most EBCDIC keyboards as well.
However, the EBCDIC C compilers I've used will also accept EBCDIC's
"solid vertical bar" character in its place, and that does appear on
the EBCDIC keyboards I've used.

It's the lack of square brackets that are really annoying. Why EBCDIC
includes the cent symbol, which is of precious little use to anyone,
and not the square brackets, which are widely used in English, is a
mystery to me. (Technically, EBCDIC doesn't "omit" the square
brackets, but their code points are device dependent, which is about
as bad. There was a thread on this in alt.folklore.computers a
while back if anyone's curious.)

Daniel Rudy's evaluation that trigraphs are no longer necessary
"today" is faulty. They're just as "necessary" now as they ever
were. Just how necessary they ever were is a different question; as
others have pointed out, it's debatable whether the language should
have sought to solve this problem, and whether trigraphs were a good
approach to doing so.

--
Michael Wojcik (E-Mail Removed)

Thanatos, thanatos! The labourer, dropping his lever,
Hides a black letter close to his heart and goes,
Thanatos, thanatos, home for the day and for ever. -- George Barker
 
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Gary
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      11-09-2005

"Jordan Abel" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> On 2005-11-08, Mark McIntyre <(E-Mail Removed)> wrote:
> > There's no hash key.....

>
> What's on shift-3?


I think the OP was perhaps referring to the UK Mac keyboard, which has no #
key. On Shift+3 I think there is £ although I'm not near my Mac at the
moment.

To get # you have to use Option-3 or Shift-Option-3 or some other finger
gymnastics. Typing trigaph ??= is easier.


 
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Jordan Abel
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      11-09-2005
On 2005-11-09, Michael Wojcik <(E-Mail Removed)> wrote:
>
> In article <436fe91e$0$11078$(E-Mail Removed)4all.nl>, Skarmander <(E-Mail Removed)> writes:
>>
>> EBCDIC has many funky versions, but do you actually know ones that do
>> not have the characters of the C trigraph set (# [ \ ] ^ { | } ~)? (This
>> is a genuine question, not an attempt at being snarky.)

>
> Yes. The standard US EBCDIC "coded graphic character set" (which
> consists of character set 600 encoded using code page 500) doesn't
> have the square brackets, for example, or the tilde. And those
> characters don't appear on the standard US keyboards for some IBM
> terminal types for systems that have C implementations available,
> such as the 5250.
>
> 00640-00500 also seems to be missing the number sign, though since
> that does appear in most older IBM character sets (eg A, AE, 930, and
> USS), it's probably widely available on EBCDIC systems. I don't
> recall offhand if it appears on the US 5250 keyboard.
>
> Hmm. I've now put my reference away, but I think the "broken"
> vertical bar character is missing from most EBCDIC keyboards as well.
> However, the EBCDIC C compilers I've used will also accept EBCDIC's
> "solid vertical bar" character in its place, and that does appear on
> the EBCDIC keyboards I've used.


The ascii character has always been a solid vertical bar as far as i
know - a broken vertical bar glyph erroneously appears in that position
on some PC video cards, and from there it's often printed that way on US
keyboards as more and more people think that's how it's supposed to
look, but broken vertical bar is at latin-1 0xA6.

> It's the lack of square brackets that are really annoying. Why EBCDIC
> includes the cent symbol, which is of precious little use to anyone,


You only think that because you're used to not having it available

> and not the square brackets, which are widely used in English, is a


Widely used? There's only one common english use for it that i can think
of.

> mystery to me. (Technically, EBCDIC doesn't "omit" the square
> brackets, but their code points are device dependent, which is about
> as bad. There was a thread on this in alt.folklore.computers a
> while back if anyone's curious.)

 
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Mark McIntyre
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      11-09-2005
On 8 Nov 2005 23:09:29 GMT, in comp.lang.c , (E-Mail Removed)
(Richard Tobin) wrote:

>In article <(E-Mail Removed)>,
>Mark McIntyre <(E-Mail Removed)> wrote:
>
>>>US keyboards aren't the problem. What characters are missing from your
>>>Mac's US keyboard?

>>
>>There's no hash key.....

>
>Really? I thought that was just on UK keyboards. What do you have
>on shift-3?


No idea. That mac is currently holding fort in my loft, as it wouldn't
accept an upgrade to OSX. It might have been a UK keyboard tho I'd be
surprised since it was bought in the US.

>Mac UK keyboards have the sterling symbol, and hash is available as
>alt-3, which is a real pain if you use normal keyboards too.


Yes, figured it was there somewhere. It just ended up being more
convenient to write my code on a PC, save on a shared drive and
compile it on the mac.

Or use trigraphs of course
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt>

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Mark McIntyre
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      11-09-2005
On Wed, 09 Nov 2005 07:29:52 GMT, in comp.lang.c ,
(E-Mail Removed) (Richard Bos) wrote:

>(E-Mail Removed) (Richard Tobin) wrote:
>
>> In article <(E-Mail Removed)>,
>> Mark McIntyre <(E-Mail Removed)> wrote:
>>
>> >>US keyboards aren't the problem. What characters are missing from your
>> >>Mac's US keyboard?
>> >
>> >There's no hash key.....

>>
>> Really? I thought that was just on UK keyboards. What do you have
>> on shift-3?

>
>Mine has a hash. I've no idea what Mark is using, but it's not a normal
>Mac US keyboard.


I'm quite happy concede it might have been a UK keyboard. If anyone
/really/ wants to know I can dig it out of the loft.

Main thing is, it doesn't have a hash key and discovering the magic
keycombinations kinda defeated one of the supposed virtues of a mac.
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt>

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Michael Wojcik
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      11-10-2005

In article <(E-Mail Removed)>, Jordan Abel <(E-Mail Removed)> writes:
> On 2005-11-09, Michael Wojcik <(E-Mail Removed)> wrote:
> >
> > Hmm. I've now put my reference away, but I think the "broken"
> > vertical bar character is missing from most EBCDIC keyboards as well.
> > However, the EBCDIC C compilers I've used will also accept EBCDIC's
> > "solid vertical bar" character in its place, and that does appear on
> > the EBCDIC keyboards I've used.

>
> The ascii character has always been a solid vertical bar as far as i
> know - a broken vertical bar glyph erroneously appears in that position
> on some PC video cards, and from there it's often printed that way on US
> keyboards as more and more people think that's how it's supposed to
> look, but broken vertical bar is at latin-1 0xA6.


Right. I think I may have confused which one was missing from the
US EBCDIC keyboards I've used, too. Thanks for the correction.

> > It's the lack of square brackets that are really annoying. Why EBCDIC
> > includes the cent symbol, which is of precious little use to anyone,

>
> You only think that because you're used to not having it available


No, I think that because it's of precious little use, as far as I
can tell. I have it available to me when I write in longhand; I
have it available with little effort on the computers that I use
daily. I never need it. I almost never see it in anything printed
in, say, the last fifty years.

> > and not the square brackets, which are widely used in English, is a

>
> Widely used? There's only one common english use for it that i can think
> of.


So? That doesn't mean they're not widely used. There's only one
common English use for parentheses, too, yet they appear all over
the place.

They're very common in much of the English prose *I* read, for
editorial insertion and for citation. The _Oxford Companion_ also
notes frequent use in dictionaries, "texts of plays", and "reports of
meetings or proceedings". They also appear in some specialized uses
(eg syntax diagrams), though those were not prominent, as far as I
know, when the original EBCDIC character set was defined.

However, editorial insertion alone makes square brackets more useful
than the cent sign. The cent sign has an obvious and completely
suitable alternative: the value scaled by 1/100 and the dollar sign,
if available, or suitable notation (eg "USD") if not. No such
entirely suitable alternative exists for square brackets.

This is now off-topic for CLC, IMO, having drifted away from the
question of trigraphs; but I certainly don't see any grounds for
arguing that the cent sign is more useful in an English character set
than the square brackets.

--
Michael Wojcik (E-Mail Removed)

There are many definitions of what art is, but what I am convinced art is not
is self-expression. If I have an experience, it is not important because it
is mine. It is important because it's worth writing about for other people,
worth sharing with other people. That is what gives it validity. (Auden)
 
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Jordan Abel
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      11-10-2005
On 2005-11-10, Michael Wojcik <(E-Mail Removed)> wrote:
>
> In article <(E-Mail Removed)>, Jordan Abel <(E-Mail Removed)> writes:
>> On 2005-11-09, Michael Wojcik <(E-Mail Removed)> wrote:
>> >
>> > Hmm. I've now put my reference away, but I think the "broken"
>> > vertical bar character is missing from most EBCDIC keyboards as well.
>> > However, the EBCDIC C compilers I've used will also accept EBCDIC's
>> > "solid vertical bar" character in its place, and that does appear on
>> > the EBCDIC keyboards I've used.

>>
>> The ascii character has always been a solid vertical bar as far as i
>> know - a broken vertical bar glyph erroneously appears in that position
>> on some PC video cards, and from there it's often printed that way on US
>> keyboards as more and more people think that's how it's supposed to
>> look, but broken vertical bar is at latin-1 0xA6.

>
> Right. I think I may have confused which one was missing from the
> US EBCDIC keyboards I've used, too. Thanks for the correction.
>
>> > It's the lack of square brackets that are really annoying. Why EBCDIC
>> > includes the cent symbol, which is of precious little use to anyone,

>>
>> You only think that because you're used to not having it available

>
> No, I think that because it's of precious little use, as far as I
> can tell. I have it available to me when I write in longhand; I
> have it available with little effort on the computers that I use
> daily. I never need it. I almost never see it in anything printed
> in, say, the last fifty years.
>
>> > and not the square brackets, which are widely used in English, is a

>>
>> Widely used? There's only one common english use for it that i can think
>> of.

>
> So? That doesn't mean they're not widely used. There's only one
> common English use for parentheses, too, yet they appear all over
> the place.
>
> They're very common in much of the English prose *I* read, for
> editorial insertion and for citation. The _Oxford Companion_ also
> notes frequent use in dictionaries, "texts of plays", and "reports of
> meetings or proceedings". They also appear in some specialized uses
> (eg syntax diagrams), though those were not prominent, as far as I
> know, when the original EBCDIC character set was defined.
>
> However, editorial insertion alone makes square brackets more useful
> than the cent sign. The cent sign has an obvious and completely
> suitable alternative: the value scaled by 1/100 and the dollar sign,


Or whatever other currency sign [I've seen arguments against using ˘ for
euro cents or whatever, and they're quite weak]

> if available, or suitable notation (eg "USD") if not. No such
> entirely suitable alternative exists for square brackets.
>
> This is now off-topic for CLC, IMO, having drifted away from the
> question of trigraphs; but I certainly don't see any grounds for
> arguing that the cent sign is more useful in an English character set
> than the square brackets.


Could the reason have been that it appeared on traditional typewriter
layouts? and maybe square brackets did not.
 
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lawrence.jones@ugs.com
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      11-10-2005
Michael Wojcik <(E-Mail Removed)> wrote:
>
> It's the lack of square brackets that are really annoying. Why EBCDIC
> includes the cent symbol, which is of precious little use to anyone,
> and not the square brackets, which are widely used in English, is a
> mystery to me.


I don't mind the cent sign so much, but the logical "not" symbol?!?

-Larry Jones

It's SUSIE! It's a GIRL! Santa would understand! -- Calvin
 
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lawrence.jones@ugs.com
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      11-10-2005
Jordan Abel <(E-Mail Removed)> wrote:
>
> The ascii character has always been a solid vertical bar as far as i
> know - a broken vertical bar glyph erroneously appears in that position
> on some PC video cards, and from there it's often printed that way on US
> keyboards as more and more people think that's how it's supposed to
> look, but broken vertical bar is at latin-1 0xA6.


The original ASCII standard also rendered it as a broken bar, which lead
to the confusion about whether it was "supposed" to be a solid bar or a
broken bar. That was fixed in the 1977 revision, I believe, but by that
time the broken bar was already solidly entrenched in some contexts.

-Larry Jones

Oh yeah? You just wait! -- Calvin
 
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