The metadata of a zettel is a collection of key-value pairs. The syntax roughly resembles the internal header of an email (RFC5322➚).
The key is a sequence of alphanumeric characters, a hyphen-minus character (
-, U+002D) is also allowed. It begins at the first position of a new line.
A key is separated from its value either by
- a colon character (
- a non-empty sequence of space characters,
- a sequence of space characters, followed by a colon, followed by a sequence of space characters.
A Value is a sequence of printable characters. If the value should be continued in the following line, that following line (
continuation line) must begin with a non-empty sequence of space characters. The rest of the following line will be interpreted as the next part of the value. There can be more than one continuation line for a value.
A non-continuation line that contains a possibly empty sequence of characters, followed by the percent sign character (
%) is treated as a comment line. It will be ignored.
Parsing metadata ends, if an empty line is found or if a line with at least three hyphen-minus characters is found.
title1:The Title title-2 : Another title title-3: A wrapped title title-4: A wrapped title with more than one continuation line % A comment line % Another comment line. No metadata anymore, because of the empty line.