(BLOCK (PARA (TEXT "The metadata of a zettel is a collection of key-value pairs.") (SOFT) (TEXT "The syntax roughly resembles the internal header of an email (") (LINK-EXTERNAL () "https://tools.ietf.org/html/rfc5322" (TEXT "RFC5322")) (TEXT ").")) (PARA (TEXT "The key is a sequence of alphanumeric characters, a hyphen-minus character (") (FORMAT-QUOTE () (LITERAL-INPUT () "-")) (TEXT ", U+002D) is also allowed.") (SOFT) (TEXT "It begins at the first position of a new line.") (SOFT) (TEXT "Uppercase letters of a key are translated to their lowercase equivalence.")) (PARA (TEXT "A key is separated from its value either by")) (UNORDERED (INLINE (TEXT "a colon character (") (FORMAT-QUOTE () (LITERAL-INPUT () ":")) (TEXT "),")) (INLINE (TEXT "a non-empty sequence of space characters,")) (INLINE (TEXT "a sequence of space characters, followed by a colon, followed by a sequence of space characters."))) (PARA (TEXT "A value is a sequence of printable characters.") (SOFT) (TEXT "If the value should be continued in the following line, that following line (") (FORMAT-QUOTE () (TEXT "continuation line")) (TEXT ") must begin with a non-empty sequence of space characters.") (SOFT) (TEXT "The rest of the following line will be interpreted as the next part of the value.") (SOFT) (TEXT "There can be more than one continuation line for a value.")) (PARA (TEXT "A non-continuation line that contains a possibly empty sequence of characters, followed by the percent sign character (") (FORMAT-QUOTE () (LITERAL-INPUT () "%")) (TEXT ") is treated as a comment line.") (SOFT) (TEXT "It will be ignored.")) (PARA (TEXT "Parsing metadata ends, if an empty line is found or if a line with at least three hyphen-minus characters is found.")) (PARA (TEXT "Some examples:")) (VERBATIM-CODE (("" . "meta")) "title1:The Title\n title-2 : Another title\ntitle-3: A wrapped\n title\ntitle-4: A\n wrapped\n title\n with\n more\n than\n one\n  continuation\n line\n% A comment line\n % Another comment line.\n\nNo metadata anymore, because of the empty line."))