Re: [go-nuts] Re: Parsing ambiguity?
On Fri, Sep 16, 2016 at 4:13 PM adonovan via golang-nuts < golang-nuts@googlegroups.com> wrote: > The grammar is indeed ambiguous, but the ambiguity is (implicitly) resolved by favoring the leftmost derivation, which is what you get from an LL(k) parser. By the same token (hah!), the grammar expresses that unary operations have higher precedence than binary ones. For example, -x + y is parsed as (-x)+y, not -(x+y). If you want a derivation other than the leftmost one, you need to use parentheses. Thank you as well. This information is valuable for fixing the issue. -- -j -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[go-nuts] Re: Parsing ambiguity?
On Friday, 16 September 2016 06:43:38 UTC-4, Jan Mercl wrote: > > Which rule selects the first parse? Can anybody please enlighten me? > Thanks in advance. > The grammar is indeed ambiguous, but the ambiguity is (implicitly) resolved by favoring the leftmost derivation, which is what you get from an LL(k) parser. By the same token (hah!), the grammar expresses that unary operations have higher precedence than binary ones. For example, -x + y is parsed as (-x)+y, not -(x+y). If you want a derivation other than the leftmost one, you need to use parentheses. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
