This is a concise compilation of all [featherdown] operators, here divided into three major types: [#Mono], [#Mirror] and [#Minimalist] operators.

§:=

Labels :::TEXT, :::MATH, :::JS mark some places where it would be unwise to overload the operators, as they already carry meaning per se. Label :::TBA means an operator is under consideration.



## Mono-operators

These operators require a single symbol, at specific positions, possibly repeated.

SYMBOL		NAME 				START OF LINE						INLINE AS PREFIX					INLINE SURROUNDING														MULTILINE FENCING (3+)
´´*´´		asterisk 			-									:::MATH								´´** **´´ [bold|§#style]													-
´´/´´		slash 				-									:::LINKS							´´// //´´ [italic|§#style]												-
´´_´´		underscore			-									:::LINKS							´´__ __´´ [underline|§#style]											´´___________´´ [§#horizontal rule] 
´´~´´		tilde 				-									-									´´~~ ~~´´ [strikethrough|§#style]										´´~~~´´ redacted section :::TBA
´´+´´		plus 				-									:::MATH								´´++ ++´´ [newly added|§#style] text									´´´+++´´ newly added section :::TBA
´´^´´		circumflex 			-									´´^´´ [short superscript|§#style]	´´^^ ^^´´ [long superscript|§#style]									´´^^^´´ [§#footnotes] section
´´¨´´		umlaut				-									´´¨´´ [short subscript|§#style]		´´¨¨ ¨¨´´ [long subscript|§#style]										-
´´@´´		at sign 			-									´´@´´ [known person|§#people]		-																		´´@@@´´ announce :::TBA
´´{{´}}´´	acute				-									-									´´{{´´}} {{´´}}´´ [§#code snippet]										´´{{´´´}}´´ [§#code block]
´´:´´		colon 				-									´´:::´´ [§#label]					´´: :´´ [§#emoji]														-
´´|´´		vertical bar 		´´|´´ [§#admonition]				-									´´|| ||´´ [spoiler|§#style]												´´|||´´ [§#polycolumn]
´´>´´		greater than 		´´>´´ [§#blockquote]				:::MATH								-																		-
´´#´´		hash sign 			´´#´´, ´´##´´... [§#ATX heading]	´´#´´ [§#input label]				´´## , ##´´ [§#input labels]											´´###´´ [§#Setex heading] (lvl. 1)
´´=´´		equal 				-									:::MATH								´´== ==´´[highlight|§#style]											´´===´´ [§#Setex heading] (lvl. 3)
´´-´´		minus 				´´-´´ [§#unnumbered list item] 		:::MATH								:::TEXT																	´´---´´ [§#Setex heading] (lvl. 5)


Only an alphanumeric expression (with dash or underscore) can follow an operator used as a prefix.
However, a surrounded expression may contain spaces and all other characters, except the operator itself.

Multiline fencing operators require always at least three equal symbols at the beginning of the line, the rest of the line is free and may be used fro options.


## Mirror operators

The following mirror-operators are often used: 

SYMBOL		OPERATOR									EFFECT															RATIONALE
´´[ ]´´		square brackets (single)					links															akin to wikipedia links
´´[1]´´		square brackets (single, number inside)		short footnote links											the format actually used in academic writing
´´[[ ]]´´	square brackets (double)					keyboard or action shortcut explanation							visually resembles a keyboard key
´´(( ))´´	parenthesis (double)						[§#caption] or image size										essentially a caption is an aside, so parenthesis would be mildly appropriate
´´{{}}´´ 	curly brackets (double)						writes enclosed expression exactly as typed, i.e. [§#verbatim]	-


The following operators are, with some exceptions, excluded: 

SYMBOL		OPERATOR						REASON FOR EXCLUSION								EXCEPTIONS
´´< >´´		lesser-greater (single)			compatibility with html tags						-
´´{ }´´		curly brackets (single)			compatibility with javascript objects and JSON		-
´´( )´´		parenthesis (single)			compatibility with normal text						common typographical replacements like (c) ´´(c)´´
´´« »´´		guillemets (single)				not easily accessible on english keyboards			shorthands/direct function calls (advanced feature)


## Minimalist operators

Minimalist operators require no more characters than the information itself they reference. Convenient!

EXAMPLE						OPERATOR										EFFECT				
´´https://example.com´´		outer link (auto)								[§#auto outer link]		
´´image.png´´				image path										[§#inline image]		
´´page.title´´				[page property|§#site and page properties]		[§#shorthands]
´´site.name´´				[site properties|§#site and page properties]	[§#shorthands]
´´1st´´						auto-superscripted correct ordinal				[§#ordinals]
´´03/06/2023´´				auto-formatted date								[§#dates]
´´** 06/09/2023 ** change´´	changestream (bold date + text)					[§#changestream]

These can be escaped with the [§#verbatim] operator if needed.


## Poly operators

The only operators using two distinct unrelated symbols are:
- even-level [§#Setex headings], visually meaningful.
- pipes ´´|´´, when separating arguments within [§#links] and [§#shorthands].
- buttons ´´[]>>>´´


[§#Poly operators] are less ergonomic to type and harder to memorise, and thus were avoided as much as possible.



### Unused operators

The following symbols were excluded for operators because they already carry sufficient meaning.

SYMBOL						INCOMPATIBILITY
backslash ´´\\´´			:::JS
question mark ´´?´´			:::TEXT
exclamation mark ´´!´´		:::TEXT, factorial :::MATH
commas ´´,´´				:::TEXT, vectors :::MATH
full stop ´´.´´				:::TEXT, decimals :::MATH, subsetting :::JS
apostrophes ´´'´´			:::TEXT, strings :::JS
quotation mark ´´"´´		:::TEXT, strings :::JS
alphanumerics ´´ABC...89´´	:::TEXT, symbols :::MATH
currencies ´´$£€...´´		:::TEXT
ordinals ´´º´´				:::TEXT
semicolon ´´;´´				:::TEXT