char and word cases

[Stephen Weeks]

I am in the process of adding in char and word cases to all the ILs.  I have to
decide how to change MACHINE.  My current thinking is to add two new kinds of
switch statements to the signature, so it looks something like:

	    val switch: {
			 test: Operand.t,
			 cases: (int * Label.t) list,
			 default: Label.t option
			} -> t
	    val switchChar: {
			 test: Operand.t,
			 cases: (char * Label.t) list,
			 default: Label.t option
			} -> t
	    val switchWord: {
			 test: Operand.t,
			 cases: (word * Label.t) list,
			 default: Label.t option
			} -> t

Any thoughts?  Any other ways you think I should go?