Question

What is the regular expression that’d match anything , except these strings:
=>, | ?

If you’re familiar with javacc, I’m trying to define my ANYTHING token as shown below:

TOKEN :
{
 <ARROW: "=>" >
|
 <ANYTHING: (["\u0001" - "\uffdc"])+>
|
 <PIPE: "|">
|
 <UPPER_CHAR: (["A"-"Z"])>
}

Thanks

Answer 1

Try something like this:

Test.jj

options {
    STATIC = false ;
}

PARSER_BEGIN(Test)
public class Test {
  public static void main(String[] args) throws Exception {
    Test parser = new Test(new java.io.StringReader("foo=>bar=baz|done"));
    parser.Parse();
  }
}
PARSER_END(Test)

TOKEN :
{
     < ARROW    : "=>" >
  |  < PIPE     : "|" >
  |  < ANYTHING : (~["=", "|"] | "=" ~[">"])+ >
}

void Parse() : 
{} 
{
  (Any())* <EOF>
}

void Any() :
{Token t;}
{
  ( t=<ARROW>    {System.out.println("ARROW    = '" + t.image + "'");}
  | t=<PIPE>     {System.out.println("PIPE     = '" + t.image + "'");}
  | t=<ANYTHING> {System.out.println("ANYTHING = '" + t.image + "'");}
  )  
}

Generate the parser classes:

javacc Test.jj

and run the main method:

java Test

will print the following for the input "foo=>bar=baz|done":

ANYTHING = 'foo'
ARROW    = '=>'
ANYTHING = 'bar=baz'
PIPE     = '|'
ANYTHING = 'done'