Unicode Escapes

This provides a regular expression definition for Unicode escapes. This is not the correct (or general) way to handle Unicode escapes. It simply makes it possible to accept Unicode escapes inside character and string literals.

Unicode Escape[3]:

\\uH[4]H[4]H[4]H[4]

This macro is invoked in definitions 30 and 32.

H[4]:

[0-9a-fA-F]

This macro is invoked in definition 3.