Re: Problem with infinite left-recursion...

cbs@ascinc.com (Casper B. Stoel) writes:


>I have a problem with left-recursion in my grammar. I am wondering if
>there is a 'standard' way of breaking the recursion? Is there an easy
>way of breaking up the rule into multiple rules?


Most left and right recursion in grammars follows a standard idiom.
To describe a list of A's left-recursively, we typically write
      list ::= list A
| A
To describe a list of A's right-recursively, we typically write
      list ::= A more-A
      more-A ::= A
| empty
Separators go in fairly obvious places, if needed.
Expressions are just lists of operands separated by operators.
If you have a lot of left-recursive rules it is tedious to
change them all, but not difficult.
--
Jon Mauney jon@mauney.com
Mauney Computer Consulting (919) 828-8053
Raleigh NC
--

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