(((meta (@ (content . "Zettelmarkup: Attributes") (name . "title"))) (meta (@ (content . "manual") (name . "role"))) (meta (@ (content . "#manual #zettelmarkup #zettelstore") (name . "tags"))) (meta (@ (content . "zmk") (name . "syntax"))) (meta (@ (content . "00001007000000 00001007010000 00001007030400 00001007030500 00001007030600 00001007030700 00001007030800 00001007030900 00001007031100 00001007031110 00001007031200 00001007031300 00001007031400 00001007040100 00001007040200 00001007040322 00001007800000 00001012931000") (name . "back"))) (meta (@ (content . "00001007000000 00001007010000 00001007030400 00001007030500 00001007030600 00001007030700 00001007030800 00001007030900 00001007031100 00001007031110 00001007031200 00001007031300 00001007031400 00001007040000 00001007040100 00001007040200 00001007040322 00001007050100 00001007800000 00001012931000") (name . "backward"))) (meta (@ (content . "1") (name . "box-number"))) (meta (@ (content . "(c) 2020-present by Detlef Stern <ds@zettelstore.de>") (name . "copyright"))) (meta (@ (content . "20210126175322") (name . "created"))) (meta (@ (content . "00001007030000 00001007040000 00001007050100 00001007050200") (name . "forward"))) (meta (@ (content . "en") (name . "lang"))) (meta (@ (content . "EUPL-1.2-or-later") (name . "license"))) (meta (@ (content . "20220630194106") (name . "modified"))) (meta (@ (content . "20220630194106") (name . "published"))) (meta (@ (content . "public") (name . "visibility")))) (p "Attributes allows to modify the way how material is presented." " " "Alternatively, they provide additional information to markup elements." " " "To some degree, attributes are similar to " (a (@ (href . "https://html.spec.whatwg.org/multipage/dom.html#global-attributes") (rel . "external")) "HTML attributes") ".") (p "Typical use cases for attributes are to specify the (natural) " (a (@ (href . "00001007050100")) "language") " for a text region, to specify the " (a (@ (href . "00001007050200")) "programming language") " for highlighting program code, or to make white space visible in plain text.") (p "Attributes are specified within curly brackets " (code "{...}") "." " " "Of course, more than one attribute can be specified." " " "Attributes are separated by a sequence of space characters or by a comma character.") (p "An attribute normally consists of an optional key and an optional value." " " "The key is a sequence of letters, digits, a hyphen-minus (" (@L (@H "&ldquo;") (kbd "-") (@H "&rdquo;")) ", U+002D, and a low line / underscore (" (@L (@H "&ldquo;") (kbd "_") (@H "&rdquo;")) ", U+005D)." " " "It can be empty." " " "The value is a sequence of any character, except space and the right curly bracket (" (@L (@H "&ldquo;") (kbd "}") (@H "&rdquo;")) ", U+007D)." " " "If the value must contain a space or the right curly bracket, the value can be specified within two quotation marks (" (@L (@H "&ldquo;") (kbd "\"") (@H "&rdquo;")) ", U+0022)." " " "Within the quotation marks, the backslash character functions as an escape character to specify the quotation mark (and the backslash character too).") (p "Some examples:") (ul (li (code "{key=value}") " sets the attribute " (em "key") " to value " (em "value") ".") (li (code "{key=\"value with space\"}") " sets the attribute to the given value.") (li (code "{key=\"value with quote \\\" (and backslash \\\\)\"}")) (li (code "{name}") " sets the attribute " (em "name") "." " " "It has no corresponding value." " " "It is equivalent to " (code "{name=}") ".") (li (code "{=key}") " sets the " (em "generic attribute") " to the given value." " " "It is mostly used for modifying behavior according to a programming language.") (li (code "{.key}") " sets the " (em "class attribute") " to the given value." " " "It is equivalent to " (code "{class=key}") ".")) (p "In these examples, " (code "key") " must conform the the syntax of attribute keys, even if it is used as a value.") (p "If a key is given more than once in an attribute, the values are concatenated (and separated by a space).") (ul (li (code "{key=value1 key=value2}") " is the same as " (code "{key\"value1 value2\"}") ".") (li (code "{key key}") " is the same as " (code "{key}") ".") (li (code "{.class1 .class2}") " is equivalent to " (code "{class=\"class1 class2\"}") ".")) (p "This is not true for the generic attribute." " " "In " (code "{=key1 =key2}") ", the first key is ignored." " " "Therefore it is equivalent to " (code "{=key2}") ".") (p "The key " (@L (@H "&ldquo;") (kbd "-") (@H "&rdquo;")) " (just hyphen-minus) is special." " " "It is called " (em "default attribute") " and has a markup specific meaning." " " "For example, when used for plain text, it replaces the non-visible space with a visible representation:") (ul (li (kbd "``Hello, world``{-}") " produces " (samp "Hello,␣world") ".") (li (kbd "``Hello, world``") " produces " (samp "Hello, world") ".")) (p "Attributes may be continued on the next line when a space or line ending character is possible." " " "In case of a quoted attribute value, the line ending character will be part of the attribute value." " " "For example:") (pre (code "{key=\"quoted\nvalue\"}")) (p "will produce a value " (kbd "quoted\\nvalue") " (where \\n denotes a line ending character).") (pre (code "::GREEN::{class=example\nbackground=grey}")) (p "is allowed, but not") (pre (code "::GREEN::{background=color:\ngreen}")) (p "However,") (pre (code "::GREEN::{background=color:\"\ngreen\"}")) (p "is allowed, because line endings are allowed within quotes.") (p "For " (a (@ (href . "00001007030000")) "block-structured elements") ", there is a syntax variant if you only want to specify a generic attribute." " " "For all line-range blocks you can specify the generic attributes directly in the first line, after the three (or more) characters starting the block.") (pre (code ":::attr\n...\n:::")) (p "is equivalent to") (pre (code ":::{=attr}\n...\n:::")) (p "For block-structured elements, spaces are allowed between the blocks characters and the attributes.") (pre (code "=== Heading {example}")) (p "is allowed and equivalent to") (pre (code "=== Heading{example}")) (p "For " (a (@ (href . "00001007040000")) "inline-structured elements") ", the attributes must immediately follow the inline markup.") (p (code "::GREEN::{example}") " is allowed, but not " (code "::GREEN:: {example}") ".") (h2 (@ (id . "reference-material")) "Reference material") (ul (li (a (@ (href . "00001007050100")) "Supported attribute values for natural languages")) (li (a (@ (href . "00001007050200")) "Supported attribute values for programming languages"))))