Brace expansion
---------------
`x{A,B}y' expands to `xAy:xBy'. For example:
foo/{1,2}/baz
expands to `foo/1/baz:foo/2/baz'. `:' is the path separator on the
current system; e.g., on a DOS system, it's `;'.
Braces can be nested; for example, `x{A,B{1,2}}y' expands to
`xAy:xB1y:xB2y'.
Multiple non-nested braces are expanded from right to left; for
example, `x{A,B}{1,2}y' expands to `x{A,B}1y:x{A,B}2y', which expands
to `xA1y:xB1y:xA2y:xB2y'.
This feature can be used to implement multiple TeX hierarchies, by
assigning a brace list to `$TEXMF', as mentioned in `texmf.in'.
You can also use the path separator in stead of the comma. The last
example could have been written `x{A:B}{1:2}y'.
Brace expansion is implemented in the source file
`kpathsea/expand.c'. It is a modification of the Bash sources, and is
thus covered by the GNU General Public License, rather than the Library
General Public License that covers the rest of Kpathsea.