Matching start and end

[Alex Duller]

Hi,
I'm trying to parse the following bit of code and want to check that the 
yIDENTIFIER words are the same (in the following case yIDENTIFIER is 
TestFir). The regular expression for an yIDENTIFIER is 
[a-zA-Z_][a-zA-Z0-9_$]*

entity TestFir is
end entity TestFir;

The rule for parsing the above is:
yENTITY yIDENTIFIER yIS
...
yEND yENTITY yIDENTIFIER ';'

thanks,
Alex