silly question: why can't i alias an expression?

[BCS]

Reply to dennis,

> why is something like that not possible? (except the missing langauge
> feature thing)
> 
> could it be a nice extension?
> 
> double A,B;
> alias ( A + B * 10 ) my_expression;
> double C = my_expression;

You can only alias things that at some level are symbols. In effect an alias 
is a link (as in soft/hard link) in the symbol table.