[antlr-interest] Optional tokens

John B. Brodie jbb at acm.org
Sun May 22 20:44:30 PDT 2005


Greetings!

On Mon, 23 May 2005 00:12:47 -0300 hammett <hammett at uol.com.br> wrote:

>I'm struggling with my grammar where I need to express that SEMI or NEWLINE 
>is required to signal the end of my statements while should be totally 
>ignored elsewhere.

...snip...

>Being concrete
>
>-- --
># a comment (Token.SKIP)
>
>class MyClass
>
>  def self.initialize
>    x, y = 1, 2
>    puts x, y
>  end
>
>end
>-- --
>
>Any help would be great!

I am sorry that I will not be very helpful in your quest, but I have to
ask the following.  Do you really expect that:

    x ; , ; y ; = ; 1 ; , ; 2

would parse to the same AST as:

    x, y = 1, 2

you did say that SEMI is to be totally ignored anywhere except at the
end of a statement...

and so just where does a statement end anyway? (answering this may
lead you to the answer of your original question)

Just Asking...
   -jbb


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