pplusplus:faq

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pplusplus:faq [2019/08/12 12:09]
zeev Move 'concerns' into a separate document, revert dynamic/weak/strong changes - "strict" means strong and static typing
pplusplus:faq [2019/08/14 13:37]
zeev
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 This is a clarifying FAQ for the idea presented on [[https://marc.info/?l=php-internals&m=156529545007909&w=2|internals@]].  It attempts to address many points that were raised repeatedly in the discussion that ensued. This is a clarifying FAQ for the idea presented on [[https://marc.info/?l=php-internals&m=156529545007909&w=2|internals@]].  It attempts to address many points that were raised repeatedly in the discussion that ensued.
 +
 +A [[pplusplus:concerns|list of concerns]] about this idea has been compiled by Arnold Daniels.  Some of them are addressed [[pplusplus:faq#what_are_the_general_concerns|here]].
  
 Note:  P++ is a temporary code name and is subject to change. Note:  P++ is a temporary code name and is subject to change.
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 ==== Why not just make a perpetual PHP 7.4 LTS and be done with it, as we move to a stricter PHP 8/9?  ==== ==== Why not just make a perpetual PHP 7.4 LTS and be done with it, as we move to a stricter PHP 8/9?  ====
  
-There are many issues with this approach Even if we disregard the fact that this leaves the huge dynamic-preferring crowd hanging with no feature or performance updates - it's impractical from a development effort point of view.  Unlike this proposal - this does, in fact, mean de-facto fork.+There are many issues with this approach, but these are probably the most important ones: 
 +  - For the dynamic crowd - more strictness is not equivalent to progress, and as such - they don't want to see future versions of PHP forcing them in that direction.  They still want to get other types of new features (non-strictness related), better performance, bug fixes, new extensions and such.  Making PHP stricter with newer versions means that for many users - upgrading would mean going backwards as far as their development preferences are concerned. 
 +  - Equally important - it'remarkably difficult - arguably impractical from a development effort point of view.  Unlike this proposal - which aims to continue supporting both dialects in the same codebase - having version that would no longer be actively developed, but would still have to be maintained for security and critical bugfixes requires resources that we simply don't have (it is arguably a kind of a fork).
  
 ==== Will I need to choose between PHP and P++? ==== ==== Will I need to choose between PHP and P++? ====
  
-Yes and no.  As mentioned above, when you install one - you'd have the other - so as far as apps go - you'd be able to run both dialects on a single server.  However, practically speaking, projects and individuals are likely to typically pick and standardize on one or the other - similarly to how things went down with strict_types.+Yes and no.  As mentioned above, when you install one - you'also have the other - so as far as apps go - you'd be able to run both dialects on a single server, even within the same app.  However, practically speaking, projects and individuals are likely to typically pick and standardize on one or the other - similarly to how things went down with strict_types.
  
  
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   - Of course, the most challenging of all - we need to find a reasonable name for this new dialect.   - Of course, the most challenging of all - we need to find a reasonable name for this new dialect.
  
 +
 +==== This is Hack all over again, isn't it?  Why would it fair any better? ====
 +
 +While conceptually the motivations for both P++ and Hack are similar - there are at least two critical differences between the two - each of which is likely sufficiently big to change the expected outcome.
 +
 +  * Hack was/is developed by a single company, and not as an open process by volunteers.  Even if the vendor that's behind it is gigantic - companies and individuals were often reluctant to standardize on a such a platform.
 +  * Perhaps more importantly - Hack (and HHVM) did not have PHP's gigantic distribution vehicle.
 +    * For Hack, it was an uphill battle for users to even give it a try:
 +      * They had to learn about its existence, and be sufficiently interested to learn more about it.
 +      * Assuming they were interested enough to give it a try - they had to go through the trouble of setting it up - using entirely different methods from the ones they were used to from the PHP days (different layout, different configuration, different everything).
 +    * With P++ - this is a radically different story from the ground up:
 +      * Every user of PHP (starting with 8.0, or whenever we make it available) - will have it available on their servers.  You will not have to install anything, or set anything up - it will simply be there.
 +      * This in turn means that virtually anybody running a Linux distro, a recent version of WAMP, a recent version of MAMP - millions of servers and development workstations will have access to P++ without having to do anything proactively.
 +      * In terms of awareness - since P++ will be a big part of the "What's new in PHP 8" - it will enjoy free marketing like Hack could only dream of - similar to the PHP 7 performance splash (few in the PHP world are unaware of it).
 +      * Of course, it doesn't mean that everyone will want to start using it - but the barrier to entry with P++ is many orders of magnitude lower than what Hack to face.
  
  
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 Arnold Daniels compiled [[https://wiki.php.net/pplusplus/concerns|a list of concerns]] about this proposal. Arnold Daniels compiled [[https://wiki.php.net/pplusplus/concerns|a list of concerns]] about this proposal.
 +
 +Some of them are addressed here:
 +
 +=== Converting PHP code to P++ code is not trivial ===
 +
 +That may be true - but it ultimately depends on what we decide to put into P++.  This proposal assumes that the contents of what we'd want to do would be similar, regardless of whether we deliver it using declare()s, Editions or a unified P++ dialect.  The premise of this proposal is that there's a large group of people in the PHP space that //want// to change PHP to be substantially different from the way it is today - making it increasingly more strong- and statically-typed.  It also assumes that this isn't bad thing - as long as don't treat it as a zero sum game with those who want to keep PHP more dynamic and loosely-typed as it presently is.
 +
 +=== PHP tooling will not support P++ ===
 +
 +It's important to understand that technologically - it'll actually be slightly simpler for vendors to support P++ vs. having to support granular declare()s or an unlimited amount of editions.  There's no reason to assume that it'll be treated any differently than if similar features/changes are introduced and delivered using a different mechanism.
 +
 +
 +=== It's not possible to do a cleanup without breaking PHP compatibility ===
 +
 +That is true - but that is actually a good reason to consider introducing this new dialect, and not vice versa.  Many proponents of strict also want to make bigger leaps in terms of breaking downwards compatibility.  Today - there's no other option except for a zero sum game with folks who may not be so fond of breaking BC (especially if it's in order to make PHP stricter).  There have been numerous instances of that in recent times, and it seems many more are in store for the future.
 +
 +Regarding the specific examples brought up by Andi:
 +  * Removing array() will have no impact on compatibility of P++/PHP - it's just syntactic salt for the more modern [] syntax.
 +  * Removing the global namespace for functions (if we do it) will only affect P++ code (i.e., access to it would be removed) - it will still be there in PHP code.
 +
 +It's important to stress that neither of these ideas were discussed to date, and may or may not be proposed for future inclusion in P++.
 +
 +=== The popularity of Python doesn't have to do with typing ===
 +
 +This document - and the proposal in general - does not claim to suggest that strong/static typing is a good or a bad idea.  It purposely doesn't take sides on which side is "right" What it does do is acknowledge that there are two substantially opposed schools of thought for PHP users - and provides a proposal on how the project can evolve to address both of them in an efficient and productive manner.  That said - clearly, there are a lot of people who //think// a strongly-typed PHP would be a better choice, so having that option may indeed increase its popularity.
 +
 +
 +=== Is there really a need for a different dialect? ===
 +
 +One of the axioms that many in the 'strict' camp appear to believe in, is a more strongly-typed and a more statically-typed language means progress - and that the main question is how we can deliver on it.  Can we do it in PHP 8 - while keeping the dynamic crowd on a legacy 7.4 version?  Should we do perhaps do it more gradually by releasing changes every few years, until we get to where we want to be?  For that crowd - it needs to be clear that for people who prefer dynamic, loosely-typed languages - strong & static typing aren't progress - and it doesn't matter if it happens overnight or over the course of a decade.
 +
 +At the same time - many others pro-strict folks are more pragmatic, and want to simply add optional strictness - along the lines of strict_types.  This, arguably - can be called progress - it's not regressive for anybody, and it does provide progress to folks who prefer a more strongly-typed / statically typed language.  This will likely be the direction we go for - which means that we'll already have different dialects available anyway.  It's really a matter of whether we'd have 2^N dialects (granular declare()s), N dialects (Editions), or 2 (PHP/P++).
 +
pplusplus/faq.txt · Last modified: 2019/08/14 13:47 by zeev