compose.md

The Compose key on the DEC LK-201, LK-401 keyboards is pressed sequentially with two other keys to input Latin-1 characters such as £ (ComposeL-) and ¶(ComposeP!).

It cannot be used while held down as Meta.

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Newsgroups: comp.sys.dec Path: cs.utk.edu!stc06.CTD.ORNL.GOV!fnnews.fnal.gov!uwm.edu !math.ohio-state.edu!howland.reston.ans.net!agate!news.Stanford.EDU !unixhub!sldb6.slac.stanford.edu!fairfield Message-ID: 1995Feb19.230712.1@sldb6.slac.stanford.edu Sender: news@unixhub.SLAC.Stanford.EDU Organization: Stanford Linear Accelerator Center References: <3i2qnj$83p@cpcw16.uea.ac.uk> Date: Mon, 20 Feb 1995 07:07:12 GMT From: fairfield@sldb6.slac.stanford.edu Subject: Re: Compose key on DEC LK401 keyboard on an Alpha 3000

In article <3i2qnj$83p@cpcw16.uea.ac.uk>, zebra@cpcw16.uea.ac.uk (Julii Brainard#) writes:

I know that people have posted messages about this before, and I have even saved a few, but there seems to be no authoritative guide for how to use the compose key on an Alpha 3000 with an LK401 keyboard to create all of those weird and wacky symbols and characters -- just a few of which may be useful in my work. [...]

    I haven't seen this topic come up very often and it's not in any
FAQ (that I know of).  The fact  is, it seems very difficult to find
this  information; usually, I expect, it's in the User's manual that
_may_ have come with the hardware (terminal), but it's  not  in  the
VMS user's manuals, or even the I/O Reference Guide, etc.  Note that
the  compose  sequences  are  common  to  all  VTxxx  terminals (and
DECterms) from the VT200_Series on  up.   [I  guess that means LK201
and LK401 keyboards, etc.]

    I _finally_ found the  compose  sequences in the Bookreader docs
for  VXT1200  X-terminals, Table 15-4.  I've reformatted the  table,
and omitted some  of  the  compose  sequences  for  characters  that
normally appear on a US keyboard (e.g., <COMPOSE> + + for the number
sign,  #).   Also,  I've omitted the dozen or so characters that you
can only access if you're using  the  ISO Latin 1 character set; the
sequences  I've listed are for the DEC Multinational character  set,
although most of these are also available in ISO Latin 1.

    -Ken

-- Kenneth H. Fairfield | Internet: Fairfield@Slac.Stanford.Edu SLAC, P.O.Box 4349, MS 98 | DECnet: 45537::FAIRFIELD (45537=SLACVX) Stanford, CA 94309 | Voice: 415-926-2924 FAX: 415-926-4335

These opinions are mine, not SLAC's, Stanford's, nor the DOE's...

=============================================================================== Note: Most sequences can also typed in reverse order, but a few must be typed in the order given.

Character	Name	Compose Sequence		Character	Name	Compose Sequence
«	opening angle brackets	<<		»	closing angle brakets	>>
¡	inverted !	!!		°	degree sign	0^
¿	inverted ?	??		¹	superscript 1	1^
¢	cent sign	C/ or C\		²	superscript 2	2^
£	pound sterling sign	L- or L=		³	superscript 3	3^
¥	yen sign	Y- or Y=		·	middle dot	.^
§	section sign	SO or S!		¼	fraction one-quarter	14
¤	currency sign**	XO		½	fraction one-half	12
©	copyright sign	CO		±	plus or minus sign	+-
ª	feminine ordinal	A_		µ	micro sign	/u
º	masculine ordinal	O_		¶	paragraph sign	P!
				ß	German small sharp s	ss
À	A grave	`A		à	a grave	`a
Á	A acute	'A		á	a acute	'a
Â	A circumflex	^A		â	a circumflex	^a
Ã	A tilde	~A		ã	a tilde	~a
Ä	A umlaut	"A		ä	a umlaut	"a
Å	A ring	*A		å	a ring	*a
Æ	A E diphthong	AE		æ	a e diphthong	ae
Ç	C cedilla	C,		ç	c cedilla	c,
È	E grave	`E		è	e grave	`e
É	E acute	'E		é	e acute	'e
Ê	E circumflex	^E		ê	e circumflex	^e
Ë	E umlaut	"E		ë	e umlaut	"e
Ì	I grave	`I		ì	i grave	`i
Í	I acute	'I		í	i acute	'i
Î	I circumflex	^I		î	i circumflex	^i
Ï	I umlaut	"I		ï	i umlaut	"i
Ñ	N tilde	~N		ñ	n tilde	~n
Ò	O grave	`O		ò	o grave	`o
Ó	O acute	'O		ó	o acute	'o
Ô	O circumflex	^O		ô	o circumflex	^o
Õ	O tilde	~O		õ	o tilde	~o
Ö	O umlaut	"O		ö	o umlaut	"o
Œ	O E diphthong*	OE		œ	o e diphthong*	oe
Ø	O slash	O/		ø	o slash	o/
Ù	U grave	`U		ù	u grave	`u
Ú	U acute	'U		ú	u acute	'u
Û	U circumflex	^U		û	u circumflex	^u
Ü	U umlaut	"U		ü	u umlaut	"u
Ÿ	Y umlaut*	"Y		ý ÿ	y umlat**	"y

• * Only available in DEC-MCS
• ** Available in Latin-1 at a different codepoint

Does Capital Y Umlaut actually work?

The FAQ lists some glyphs which are not Latin-1 characters. Do they work on a VT340 in Latin-1 mode? No. They share the same code-point as Latin-1 glyphs, so they only work in DEC-MCS mode. (Set Up Key -> General -> User Pref Charset). Hackerb9 recommends using Latin-1 mode for modern VT340 usage.

Table of conflicting characters between MCS and Latin-1

The two characters in each row have the same code point.

Code	DEC-MCS	Name	Compose Sequence		Latin-1	Name	Compose Sequence
0xD7	Œ	O E diphthong	OE		×	Multiplication	xx
0xF7	œ	o e diphthong	oe		÷	Division	-:
0xDD	Ÿ	Y umlaut	"Y		Ý	Y acute	'Y
0xDD	ÿ	y umlaut	"y		ý	y acute	'y
0xFF		Invalid			ÿ	y umlaut	"y
0xA8	¤	Currency sign	XO		¨	Diaeresis	""
0xA4		Undefined			¤	Currency sign	XO

Sidenote: Character 0xFF (y umlaut) is invalid when the VT340 is set to MCS and the glyph will be omitted instead of being substituted with the backwards question mark (DEC replacement character).

Latin-1 VT340 compose keys not found in Shufford's DEC FAQ

Code	Character	Name	Compose Sequence
a0	" "	No-break space	SpaceSpace
a6	¦	Broken pipe	PipePipe
a8	¨	Diaeresis	""
ac	¬	Not	-,
ad	­	Soft hyphen	--
ae	®	Registered	RO
af	¯	Macron	^-
b4	´	Acute accent	''
b8	¸	Cedilla	,,
be	¾	Three quarters	34
d0	Ð	Icelandic Eth	-D
d7	×	Multiplication	xx
dd	Ý	Y acute	'Y
de	Þ	Icelandic Thorn	TH
f0	ð	Icelandic eth	-d
f7	÷	Division	-:
fd	ý	y acute	'y
fe	þ	Icelandic thorn	th
ff	ÿ	y umlaut	"y

X11 compose is very similar

X11 uses a near superset of the compose key sequences on the VT340. To use it, one just needs to assign a key to be "Compose" (e.g., setxkbmap -option compose:rctrl). See the file /usr/share/X11/locale/en_US.UTF-8/Compose for all possible compose sequences. Also see /usr/share/X11/locale/iso8859-1/Compose for a much shorter list of keys which more closely fits with the VT340.

Compose keys from X11 Compose

DEC	HEX	OCT	CHAR	NAME	X11 Compose
160	a0	240		Non-breakable space	spacespace
166	a6	246	¦	Broken bar	!^
168	a8	250	¨	Diaeresis	""
172	ac	254	¬	Not	-,
173	ad	255	­	Soft hyphen	--
175	af	257	¯	Macron	^-	X11 adds a space at the end
180	b4	264	´	Acute accent	''
208	d0	320	Ð	Icelandic Eth	-D	X11 specifies ~ instead of -
215	d7	327	×	Multiply	xx
221	dd	335	Ý	Y-acute	'Y
222	de	336	Þ	Icelandic Thorn	TH	X11 uses ~ T
240	f0	360	ð	Icelandic eth	-d	X11 uses ~ instead of -
247	f7	367	÷	Divide	-:
253	fd	375	ý	y-acute	'y
254	fe	376	þ	Icelandic thorn	th	X11 uses ~ t

Redundant ASCII

The Compose key on the VT340 (and in X11) allows one to type some ASCII characters that may be difficult to access on some keyboards. Since they merely replace keys that exist on the US keyboard, they were not listed in Shufford's DEC keyboard FAQ.

Character	Name	Compose Sequence
{	Left curly brace	-(
}	Right curly brace	)-
[	Left square bracket	((
]	Right square bracket	))
#	Number sign	++
\	Backslash	//
Pipe	Pipe symbol	/^

Aliases available in X11, missing on VT340

These additional sequences are listed as aliasses in X11. Do they also work on the VT340? Nope. Just use the standard sequences.

character	Name	X11 Compose Alias	Standard Compose
°	Degree	oo	0^
µ	Micro	mu	/u

X11 UTF-8 Compose

X11 changes the meaning of some compose sequences when LANG=en_US.utf-8 (versus LANG=en_US.iso8859-1).

feminine and masculine ordinals

In X11's UTF-8 encoding, _a is ā (a with macron) and _o is ō (o with macron). Instead X11 requires ^_a and ^_o for ª and º

Degree and superscript zero

In X11, ^0 is ⁰ (superscript zero), use oo for degree.

Many Unicode Characters not possible on VT340

With a Unicode locale, the Compose key in X11 has a much wider repertoire. Do not expect the VT340 to be able to do sequences like:

Char	Name	Compose sequence
⌣	Smile	:)
♥	Heart	<)3/kbd>

However, DEC APL does somehow allow redefining the compose keys so as to make unusal glyphs. This has been tested with the VWS terminal emulator, but needs to be tested with a VT340.