Larry Wall wrote:
And there aren't that many regexish languages anyway. So I think :syntax is relatively useless except for documentation, and in practice people will almost always omit it, which makes it even less useful, and pretty nearly kicks it over into the category of multiplied entities for me.
Its surprising how many are out there. Even if we ignore the various dialects of standard rexen, we can find interesting examples such as PSL, a language for specifying temporal assertions, for hardware design: http://www.project-veripage.com/psl_tutorial_5.php. Whether one would want to fold this syntax into a C<rule> is a different question.
There are actually a number of competing languages in this space. E.g. http://www.pslsugar.org/papers/pslandsva.pdf.