Java, JavaCC: How to parse characters outside the BMP?
java, javacc, unicode, utf-16
Solution
Have a look at `Character.toCodePoint(char, char)` which will convert a surrogate pair into a full range code point. `String.codePointAt` may well be useful to you, too.
There's a lot of other surrogate support within Character and String. To know exactly which methods to call, we'd need to know the exact details of your situation.
Problem
I am referring to the XML 1.1 spec. Look at the definition of `NameStartChar`: `NameStartChar ::= ":" | [A-Z] | "_" | [a-z] | [#xC0-#xD6] | [#xD8-#xF6] | [#xF8-#x2FF] | [#x370-#x37D] | [#x37F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]` If I interpret this correctly, the last range (`#x10000-#xEFFFF`) goes beyond the UTF16 range of Java's `char` type. So it must be UTF32, right? So, I need to check pairs of `char` against this range, instead of single `char`s, right? My questions are: - How do I check for such character ranges using standard Java methods? - How is it possible to define such ranges in JavaCC? - JavaCC complains about `\u10000` and `\uEFFFF` Thank you! NOTE: Don't worry, I am not trying to write an own XML-parser. EDIT: I am writing a parser, which would check if text input from miscellaneous (non-XML) text formats would match valid XML names.