Re: Better types without runtime checking

One Tue, Jun 5, 2018 at 2:28 AM Yasuo Ohgaki <yohgaki@ohgaki.net> wrote: > On Tue, Jun 5, 2018 at 4:23 PM Rudolph Gottesheim <r.gottesheim@loot.at> > wrote: > >> There's always a lot of talk about types in the PHP community. >> Specifically, many developers want property types, generics, function >> signature types, union and intersection types, and more. Those talks >> (and RFCs) always end with the same result: "We can't do it because >> performance issues." >> >> Has there ever been a discussion about adding some of those features >> syntactically, but ignoring them during runtime? At least until someone >> finds a performant way to check them at runtime. That way we could have >> advanced type checking in our editors at least. >> >> The idea will sound familiar to TypeScript users. It works great for >> that language. >> >> I'm excited to hear your opinions. > > DbC style has no performance issue at all. In addition, you can perform > much better validation than simple type checks. > > function f($username) { > assert(is_string($username) && preg_match('\\A[a-z]\\z', $username); > .... > } Assertions are not a replacement for syntactical type declarations, since they cannot be checked until runtime. They are also more verbose, and don't help editors provide autocompletion when writing code. +1 to the possibility of a PHP static type checker which can be run independently from the runtime to support more advanced types without degrading performance.