Directives are similar to a WikiLink in form, except they
begin with ! and may contain parameters. The general form is:
[[!directive param="value" param="value"]]
This gets expanded before the rest of the page is processed, and can be used to transform the page in various ways.
The quotes around values can be omitted if the value is a simple word. Also, some directives may use parameters without values, for example:
[[!tag foo]]
A directive does not need to all be on one line, it can be wrapped to multiple lines if you like:
[[!directive foo="baldersnatch"
bar="supercalifragilisticexpialidocious" baz=11]]
Also, multiple lines of quoted text can be used for a value. To allow quote marks inside the quoted text, delimit the block of text with triple-double-quotes or triple-single-quotes:
[[!directive text="""
1. "foo"
2. "bar"
3. "baz"
""" othertext='''
1. 'quux'
2. "foo"
''']]
If you want to put text with triple quotes into a parameter value, you can use perl-style here-doc syntax, even nesting it like this:
[[!directive text=<<OUTER
[[!otherdirective <<INNER
inner text
INNER]]
outer text
OUTER]]
ikiwiki also has an older syntax for directives, which requires a space in
directives to distinguish them from wikilinks. This
syntax has several disadvantages: it requires a space after directives with
no parameters (such as [[pagecount ]]), and it prohibits spaces in
wikilinks. ikiwiki now provides the !-prefixed
syntax shown above as default. However, ikiwiki still supports wikis using
the older syntax, if the prefix_directives option is disabled.