Hex constants (idle question)

[Enrico Colombini <erix@...>]

I'd like my users to be able to type in hexadecimal (and possibly binary) 
constants in as painless a way as possible. Currently I have:

  n = htoi("c3")

which of course works fine, but makes complex expressions less readable for an 
inexperienced user. 
Is there a simpler way? I thought of:
  
  n = hex.c3

but it would work only for hex constants beginning with a letter. The 
alternative:

  n = const.h3c

seems ugly and error-prone.
Did I miss other possibilities?

  Enrico