Aliasing frequently used patterns in Lex

Question

I have one regexp, which is used in a several rules. Can I define alias for it, to keep this regexp definition in one place and just use it across the code? Example:

[A-Za-z0-9].[A-Za-z0-9_-]* (expression) NAME (alias)
...
%%
NAME[=]NAME {
  //Do something.
}
%%

Answer 1

It goes in the definitions section of your lex input file (before the %%) and you use it in a regular expression by putting the name inside curly braces ({…}). For example:

name        [A-Za-z0-9][A-Za-z0-9_-]*

%%

{name}[=]{name}  { /* Do something */ }