On Tue, Nov 8, 2016 at 12:34 PM Fleshgrinder <p...@fleshgrinder.com> wrote:
> This requires associativity, as Python has it. > > https://docs.python.org/3/reference/expressions.html#comparisons > > The problem, as explained in the Python reference, is that in `x < y < > z` the variables `x` and `z` are never compared against each other. > This, however, works great almost always and nothing is wrong in doing > so in my opinion. > > That change would actually be brutally easy since we only need to change > the `%nonassoc` to `%left` and we are done. > > https://github.com/php/php-src/blob/master/Zend/zend_language_parser.y#L73 I don't think that alone allows the chaining of comparisons. I'd have to look closer, but it'd seem to me that zend_ast_create_binary_op (ZEND_AST_BINARY_OP) evaluation might need to be amended as well. Seems it eventually calls a `op(zval*,zval*,zval*) so the evaluated end of: one op would be a true/false, when comparing against another boolean op. Regardless of implementation, the core question you raised was should something like it exist, I'm still a strong yes on that front. I'd just promote introducing the left precedence and allowing the arbitrary chains of comparison, rather than just a single interval comparison. cheers -- Dave
