define variables and expand its variables

input sample.inp

name=John
quantity=23

Hello $name,


You will have 23 boxes.

Thanks

output

Hello John,


You will have 23 boxes.

Thanks

jflex

/**
copy as java comment
*/


%%

%public
%class ClassName

//%debug
%standalone

%unicode

%{
  String name;
  String quantity;

%}

%%

"name=" [a-zA-Z]+  
    { 
      name = yytext().substring(5); 
    }

"quantity=" [0-9]+  
    { 
      quantity = yytext().substring("quantity=".length()); 
    }

"$name"  { System.out.print(name); }
"$quantity"  { System.out.print(quantity); }

jflex simple.flex
javac ClassName
java ClassName sample.inp