Zeev, >> And note that this can only work with strict types since you can do the >> necessary type inference and reconstruction (both forward from a function >> call, and backwards before it). > > Please do explain how strict type hints help you do inference that you > couldn't do with dynamic type hints. Ultimately, your whole argument hinges > on that, but you mention it in parentheses almost as an afterthought. > I claim the opposite - you cannot infer ANYTHING from Strict STH that you > cannot infer from Coercive STH. Consequently, everything you've shown, down > to the C-optimized version of strict_foo() can be implemented in the exact > same way for very_lax_foo(). Being able to optimize away the value > containers is not unique to languages with strict type hints. It's done in > JavaScript JIT engines, and it was done in our JIT POC.
I do here: http://news.php.net/php.internals/83504 I'll re-state the specific part in this mail: <?php declare(strict_types=1); function foo(int $int): int { return $int + 1; } function bar(int $something): int { $x = $something / 2; return foo($x); } ^^ In that case, without strict types, you'd have to generate code for both integer and float paths. With strict types, this code is invalid. You can tell because you know the function foo expects an integer. So you can infer that $x will have to have the type integer due to the future requirement. Which means the expression "$something / 2" must also be an integer. We know that's not the case, so we can raise an error here. At that point the developer has the choice to explicitly cast or put in a floor() or one of a number of options. The function "bar" itself didn't give us that information. We needed to use the type information from foo() to infer the type of $x prior to foo()'s call. Or more specifically, we inferred the only stable type that it could be. Which let us determine that $x's assignment was where the error was (since it wasn't a stable assignment). Without strict typing this code is always stable, but you still need to generate full type assertions in a compiled version of foo() and use ZVALs for $x, hence reducing the effect of the optimization significantly. Anthony -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
