In the default modern stropping regime supported by GCC comments are
written between { and } delimiters, and can be nested
to arbitrary depth. For example:
foo +:= 1; { Increment foo. }
If UPPER stropping is selected, this compiler additionally supports
three classical Algol 68 comment styles, in which the symbols marking
the beginning of comments are the same than the symbols marking the
end of comments and therefore can’t be nested: comment
... comment, co ... co and # .. #. For
example:
comment This is a comment. comment foo := 10; co this is also a comment co foo +:= 1; # and so is this. #
Unless -std=algol68 is specified in the command line, two
styles of nestable comments can be also used with UPPER stropping: the
already explained { ... } and a “bold” style that uses
code ... edoc. For example:
foo := 10; { this is a nestable comment in brief style. }
foo +:= 1; note this is a nestable comment in bold style. eton.
note
"Bold" nestable comments.
eton
{ "Brief" nestable comments. }
In UPPER stropping all comment styles are available, both classic and
nestable. In modern SUPPER stropping, which is based on reserved
words, only { ... } is available.