Magic top-left key to implement complex characters

[lud]

Context

I don't see if this is possible at the moment, but I think no.

Describe your suggested feature

In messageease, on the top-left square of the 9-grid, there is a © character that will enable combinations of letters.

So for instance cc© becomes ç, <<© becomes «, etc..

There are a lot, for instance I could do the "lambda" symbol for maths, but I can't remember the invocation. I cannot find the list of all possible combinations.

Would you consider implementing this feature?

Other details

No response

Acknowledgements

• I have searched the existing issues and this is a new one, NOT a duplicate or related to another open issue.
• This is a single feature request, in case of multiple feature requests I will open a separate issue for each one (they can always link to each other if related)
• I have written a short but informative title.
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[slashdevslashurandom]

This feature would be reminiscent of the "Compose key" that is available on Linux systems.

Here is a list of X11 dead key and compose key combinations (in this situation we are looking for those that include Multi_key).

The only difference is that, when using the Compose key, one is supposed to input it first and then type in the keys for the character, so Compose o c makes the copyright symbol, Compose a e makes æ, Compose ^ j makes ĵ, etc.

[nightkr]

Yeah, I'd like to support this, I'm just not sure we're the correct place to maintain that kind of mapping table. Maybe if we can yoink something from CLDR or X11...

[slashdevslashurandom]

For comparison, this is how the developers of Unexpected Keyboard do character composing -- seems like they just have a list of predefined characters for specific accents, and if that's unavailable, either plug in a composing character codepoint or return failure.

As for the X11 database, it's usually taken from the libX11 source codes. In the libX11 source code file, the /libX11-1.8/nls/en_US.UTF-8/Compose.pre file contains most of the compose key definitions (including ones for non-Latin languages).

[nightkr]

Note to self: https://www.unicode.org/versions/Unicode15.1.0/ch03.pdf#G30602

[nightkr]

Online link to the Xlib compose definition: https://gitlab.freedesktop.org/xorg/lib/libx11/-/blob/041b5291f0956c5cda5054be2981c0d02b009a4c/nls/iso8859-1/Compose.pre

[Phidica]

I'm not sure if this will be useful, but I thought I'd include it in the discussion for completeness. @lud mentioned not being able to find a table of all the combinations supported in MessagEase, but I found one in the "How To..." section in the app and include it at the bottom of this comment.

While I suppose that some of these (like the accented letters) might be covered by an external library that could be relied upon by Flickboard, I think that others (like the maths symbols, punctuation, and Greek letters) are custom to MessagEase. For instance to complete @lud's example, typing a capital lambda is done with L and A.

I don't particularly mind if the required combination changes, but I think it would be nifty to be able to type some of these symbols with Flickboard.

MessagEase table of special characters

Symbol	Description	Combination
ƒ	script f	f and /
"	low double comma quote	, and ,
…	horizontal ellipsis	. and .
†	dagger	+ and |
‡	double dagger	+ and +
‰	per mille	% and %
Š	upper s hacek	S and ^
Œ	uppercase oe	O and E
'	single open comma quote	< and '
'	single close comma quote	> and '
"	double open comma quote	` and `
"	double close comma quote	´ and ´
–	en dash	n and -
—	em dash	m and -
˜	spacing tilde	~ and -
™	trademark	T and M
š	lowercase s hacek	s and ^
œ	lowercase oe chr	o and e
Ÿ	uppercase Y diaeresis	Y and ¨
¡	inverted exclamation	! and /
¢	cent sign	c and /
£	pound sterling	L and -
¤	general currency sign	o and =
¥	yen sign	Y and =
¦	broken vertical bar	| and -
§	section sign	S and /
©	copyright	c and o
«	left angle quote, guillemotleft	< and <
¬	not sign	- and |
®	registered trademark	o and r
¯	macron accent	- and ^
±	plus or minus	+ and -
∓	minus or plus	- and +
♂	male sign	o and >
♀	female sign	o and +
²	superscript two	2 and ^
³	superscript three	3 and ^
µ	micro sign	m and u
¶	paragraph sign	p and p
¹	superscript one	1 and ^
»	right angle quote, guillemotright	> and >
¼	fraction one-fourth	1 and 4
½	fraction one-half	1 and 2
¾	fraction three-fourths	3 and 4
¿	inverted question mark	? and /
×	multiply sign	x and x
÷	division sign	- and :
ⁿ	Superscript n	n and ^
Ω	Ohm sign	o and h
∂	Partial Differential	p and d
√	Square root sign	s and q
√	Square root sign	r and 2
∞	Infinity sign	o and o
∫	Integral sign	s and \
≈	Almost equal sign	~ and =
≠	Not equal sign	/ and =
≤	Less than or equal to	< and =
≥	Greater than or equal to	> and =
₣	French Franc Sign	f and f
₤	Italian Lira Sign	l and r
₧	Spanish Peseta Sign	p and z
‽	Interrobang	! and ?
À	capital a, grave accent	A and `
Á	capital a, acute accent	A and ´
Â	capital a, circumflex accent	A and ^
Ã	capital a, tilde	A and ~
Ä	capital a, dieresis/umlaut mark	A and ¨
Å	capital a, ring	A and °
Æ	capital ae diphthong (ligature)	A and E
Ą	capital a, ogonek (ligature)	A and C
Ç	capital C, cedilla	C and C
Č	capital C with háček	C and ^
Ć	capital C , acute accent	C and ´
Ð	capital eth, icelandic	D and -
Ď	capital D with háček	D and ^
È	capital E, grave accent	E and `
É	capital E, acute accent	E and ´
Ê	capital E, circumflex accent	E and ^
Ë	capital E, dieresis/umlaut mark	E and ¨
Ě	capital E with háček	E and ^
Ę	capital E, ogonek (ligature)	E and C
Ė	capital E, dot (ligature)	E and .
Ì	capital i, grave accent	I and `
Í	capital i, acute accent	I and ´
Î	capital i, circumflex accent	I and ^
Ï	capital i, dieresis/umlaut mark	I and ¨
Į	capital i, ogonek (ligature)	I and C
İ	capital i, dotted (Turkish)	I and .
ı	small i, dottles (Turkish)	i and .
Ğ	capital G, breve (Turkish)	G and ~
ğ	small g, breve (Turkish)	g and ~
Ň	capital N with háček	N and ^
Ñ	capital n, tilde	N and ~
Ò	capital o, grave accent	O and `
Ó	capital o, acute accent	O and ´
Ô	capital o, circumflex accent	O and ^
Õ	capital o, tilde	O and ~
Ö	capital o, dieresis/umlautmark	O and ¨
Ő	capital o, double acute /umlautmark	O and "
Ø	capital o, slash	O and /
Ř	capital R with háček	R and ^
Ť	capital T with háček	T and ^
Ù	capital u, grave accent	U and `
Ú	capital u, acute accent	U and ´
Û	capital u, circumflex accent	U and ^
Ü	capital u, dieresis/umlautmark	U and ¨
Ů	capital U with ring	U and °
Ű	capital U, double acute /umlautmark	U and "
Ų	capital U, ogonek (ligature)	U and C
Ū	capital U, bar (ligature)	U and -
Ŭ	capital U, breve (ligature)	U and U
Ŭ	capital U, breve (ligature)	U and u
Ý	capital y, acute accent	Y and ´
Ž	capital Z with háček	Z and ^
Þ	capital thorn, icelandic	I and P
ß	small sharp s, german (sz ligature)	s and s
à	small a, grave accent	a and `
á	small a, acute accent	a and ´
â	small a, circumflex accent	a and ^
ã	small a, tilde	a and ~
ä	small a, dieresis/umlaut mark	a and ¨
å	small a, ring	a and °
æ	small ae diphthong (ligature)	a and e
ą	small a, ogonek (ligature)	a and c
ç	small c, cedilla	c and c
č	small c with háček	c and ^
ć	small c, acute accent	c and ´
ð	small eth, icelandic	d and -
ď	small d with háček	d and ^
è	small e, grave accent	e and `
é	small e, acute accent	e and ´
ê	small e, circumflex accent	e and ^
ë	small e, dieresis/umlaut mark	e and ¨
ě	small e with háček	e and ^
ę	small e, ogonek (ligature)	e and c
ė	small e, dot (ligature)	e and .
ì	small i, grave accent	i and `
í	small i, acute accent	i and ´
î	small i, circumflex accent	i and ^
ï	small i, dieresis/umlaut mark	i and ¨
į	small i, ogonek (ligature)	i and c
ň	small n with háček	n and ^
ñ	small n, tilde	n and ~
ò	small o, grave accent	o and `
ó	small o, acute accent	o and ´
ô	small o, circumflex accent	o and ^
õ	small o, tilde	o and ~
ő	small o, double acute /umlautmark	o and "
ö	small o, dieresis/umlaut mark	o and ¨
ø	small o, slash	o and /
ř	small r with háček	r and ^
ŝ	small s with háček	s and ^
Ŝ	Capital S with háček	S and ^
š	small s with caron	s and ˇ
Š	Capital S with caron	S and ˇ
ş	small s with cedilla	s and >
Ş	Capital S with cedilla	S and >
ţ	small t with cedilla	t and >
Ţ	Capital T with cedilla	T and >
ť	small t with háček	t and ^
ù	small u, grave accent	u and `
ú	small u, acute accent	u and ´
û	small u, circumflex accent	u and ^
ü	small u, dieresis/umlaut mark	u and ¨
ů	small u with ring	u and °
ű	small u, double acute /umlautmark	u and "
ų	small u, ogonek (ligature)	u and c
ū	small u, bar (ligature)	u and -
ŭ	small U, breve (ligature)	u and U
ŭ	small U, breve (ligature)	u and u
ý	small y, acute accent	y and ´
ž	small z with háček	z and ^
þ	small thorn, icelandic	i and p
ÿ	small y, dieresis/umlaut mark	y and ¨
Α	Uppercase Alpha	A and L
Β	Uppercase Beta	B and E
Γ	Uppercase Gamma	G and A
Δ	Uppercase Delta	D and E
Ε	Uppercase Epsilon	E and P
Ζ	Uppercase Zeta	Z and E
Η	Uppercase Eta	E and T
Θ	Uppercase Theta	T and E
Ι	Uppercase Iota	I and O
Κ	uppercase Kappa	K and A
Λ	uppercase Lambda	L and A
Μ	uppercase Mu	M and U
Ν	uppercase Nu	N and U
Ξ	uppercase Xi	X and I
Ο	uppercase Omicron	O and N
Π	uppercase Pi	P and I
Ρ	uppercase Rho	R and O
Σ	uppercase Sigma	S and I
Τ	uppercase Tau	T and A
Υ	uppercase Upsilon	U and P
Φ	uppercase Phi	P and H
Χ	uppercase Chi	C and H
Ψ	uppercase Psi	P and S
Ω	uppercase Omega	O and M
α	Lowercase Alpha	a and l
β	Lowercase Beta	b and e
γ	Lowercase Gamma	g and a
δ	Lowercase Delta	d and e
ε	Lowercase Epsilon	e and p
ζ	Lowercase Zeta	z and e
η	Lowercase Eta	e and t
θ	Lowercase Theta	t and e
ι	Lowercase Iota	i and o
κ	Lowercase Kappa	k and a
λ	Lowercase Lambda	l and a
μ	Lowercase Mu	m and u
ν	Lowercase Nu	n and u
ξ	Lowercase Xi	x and i
ο	Lowercase Omicron	o and n
π	Lowercase Pi	p and i
ρ	Lowercase Rho	r and o
ς	Lowercase Final Sigma	f and s
σ	Lowercase Sigma	s and i
τ	Lowercase Tau	t and a
υ	Lowercase Upsilon	u and p
φ	Lowercase Phi	p and h
χ	Lowercase Chi	c and h
ψ	Lowercase Psi	p and s
ω	Lowercase Omega	o and m

[lverweijen]

I know that vim and emacs use RFC1345 (with their own modifications) for making special characters, which has a lot of symbols.

It does have a few downsides that you may want to think about:

• It's no longer updated. It's an old standard.
• It doesn't have a euro sign €. This symbol is on the main layout, but other modern symbols might be missing.
• Instead of writing e/ to get é it would make more sense to write e´ instead. This is because the rfc assumes ` and ´ are not available on old computer keyboards, so it uses slashes for this. It also uses e: instead of e" for dotted e.

[nightkr]

@lverweijen

Yeah, hm.. that's a pretty big downside. But we can always make the source an option or something, and as you say it doesn't have to be the only way to enter characters.

@Phidica

Thanks for the list! Looking at it, it seems like there are basically two different "patterns" going on: "Character with accent" (a¨ -> ä) and "smash these two regular characters together" (ae -> æ). I think, ideally, the former should hopefully already be solved by dead letters/zalgo mode, so the latter is probably what I'd focus on for this.