Unable to use "/" in regular expressions

[nagaozen]

e.g. extending the example to:

object {
  string name;
  string description?;
  string homepage /^http:\/\//;
  integer {1500,3000} invented;
}*;

while /^http:\/\// is a valid regular expression, it makes orderly fire an error:

Error: Lexical error on line 5. Unrecognized text.
...g homepage /^http:\/\//;  integer {1500
-----------------------^