I too have had to maintain PHP code that I've since replaced with Scala, and our Scala production cycle has gotten quite fast indeed. The thing about Scala is: the compiler is the worst, slowest part of the language by far, and admittedly frustrating. But I've also found it's not a deal-breaker. Particularly, using it with the Play framework gives you request-triggered recompiling, so you can go through the change code-browser reload-change code process just like you do with PHP. And the iteration happens just slightly slower than with PHP. But you get the benefits of static typing which guarantees program correctness unlike PHP. The lack of this guarantee means PHP is actually not as productive as people say. If something compiles at all in Scala it tends to work the way you intended, and you don't have to go through some user flow or interaction in order to find whether or not the change you made works. Obviously, sometimes you do, esp. if you change front-end js. But most of the time I have found I don't, provided that the program compiles.
So I'm not buying this argument from Adams that the PHP iteration is necessasrily faster. It definitely used to be that way, but I think other languages have caught up.
We are churning out complete web services two or three at a time in 6 person shop, every month or so. We weren't as productive in PHP. Maybe that's just us getting better as programmers, but I also think it has a little to do with the bugs and other things caused by the lack of static typing and various language quirks.
Plus, Scala has access to the entire Java ecosystem, which is arguably as or more mature than the PHP ecosystem. So I don't spend a lot of time reinventing the wheel, as the Facebook engineers have done with their custom framework.
I would say that PHP, or any dynamic language for that matter, is going to result in faster iterations just by virtue of never having to wait for the compiler to catch up.
Even with incremental compilation and SBT subprojects (i.e. modules to keep recompiled code to a minimum) there's a compile time hit on _every_ source file change; that adds up over the lifetime of a project.
You guys may be more productive now than you were with PHP, but that's likely due more to the awesome libraries you're using than Scala development being inherently faster than PHP.
Right. But my argument is that the compile hit as at least mostly compensated for by the guarantee of program correctness, which PHP doesn't have. Forcing you to go through a user interaction to see if your change broke anything, which takes time.
Goes both ways. In PHP you can take an arbitrarily complex object graph and marshall it to JSON with a few keystrokes; in Scala, unless you're working with MongoDB or other native JSON speaking backeend, you've got to go through a laborious manual process to do the same...for each complex object.
That's partly why Dynamic came about in Scala, to deal with the case where, shit, you've already got a type safe represention of an object in Scala, and now you have to create a type safe JSON version of the same -- pointless double duty...PHP, Python, Groovy, Ruby, etc. win this particular battle.
I am, BTW, completely playing devil's advocate here ;-), Scala's my daily bread; PHP, wow, I did some horrible things [shudder]
That's true about JSON - it can be quite tedious if you have to write JSON reads and writes for things like JSON validation. But Play can autogenerate the reads/writes combinators for cases where validation isn't needed, so it ends up being as simple as putting a JsonFormatter in your companion object for a case class - 1 line. Play (and Jerkson) usually knows what to do with it, assuming all nested classes have json formatters in their companion objects, too.
In PHP cycles are slightly faster, but Scala lets you do away with lot less cycles. Not only because of awesome library, but also because excellent IDE support with instant type-checking.
heh, that's a stretch, perhaps compared to 3 years ago the IDE story in Scala is all roses. It's improved with time, but I still get arggghhh inducing moments where a given source file turns into a sea of red Xs despite SBT compiling the code just fine. Often an ./eclipse -clean is the only way to right the ship.
Perhaps IntelliJ provides a different experience (although I've heard there are issues with the Scala plugin there as well).
IntelliJ IDEA provides a different experience. I tried the eclipse plugin a month ago - much better than it was 2 years ago, but still far behind Idea. Also, keep in mind, we're comparing it to PHP and not Java.
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I too have had to maintain PHP code that I've since replaced with Scala, and our Scala production cycle has gotten quite fast indeed. The thing about Scala is: the compiler is the worst, slowest part of the language by far, and admittedly frustrating. But I've also found it's not a deal-breaker. Particularly, using it with the Play framework gives you request-triggered recompiling, so you can go through the change code-browser reload-change code process just like you do with PHP. And the iteration happens just slightly slower than with PHP. But you get the benefits of static typing which guarantees program correctness unlike PHP. The lack of this guarantee means PHP is actually not as productive as people say. If something compiles at all in Scala it tends to work the way you intended, and you don't have to go through some user flow or interaction in order to find whether or not the change you made works. Obviously, sometimes you do, esp. if you change front-end js. But most of the time I have found I don't, provided that the program compiles.
So I'm not buying this argument from Adams that the PHP iteration is necessasrily faster. It definitely used to be that way, but I think other languages have caught up.
We are churning out complete web services two or three at a time in 6 person shop, every month or so. We weren't as productive in PHP. Maybe that's just us getting better as programmers, but I also think it has a little to do with the bugs and other things caused by the lack of static typing and various language quirks.
Plus, Scala has access to the entire Java ecosystem, which is arguably as or more mature than the PHP ecosystem. So I don't spend a lot of time reinventing the wheel, as the Facebook engineers have done with their custom framework.
I would say that PHP, or any dynamic language for that matter, is going to result in faster iterations just by virtue of never having to wait for the compiler to catch up.
Even with incremental compilation and SBT subprojects (i.e. modules to keep recompiled code to a minimum) there's a compile time hit on _every_ source file change; that adds up over the lifetime of a project.
You guys may be more productive now than you were with PHP, but that's likely due more to the awesome libraries you're using than Scala development being inherently faster than PHP.
Right. But my argument is that the compile hit as at least mostly compensated for by the guarantee of program correctness, which PHP doesn't have. Forcing you to go through a user interaction to see if your change broke anything, which takes time.
Goes both ways. In PHP you can take an arbitrarily complex object graph and marshall it to JSON with a few keystrokes; in Scala, unless you're working with MongoDB or other native JSON speaking backeend, you've got to go through a laborious manual process to do the same...for each complex object.
That's partly why Dynamic came about in Scala, to deal with the case where, shit, you've already got a type safe represention of an object in Scala, and now you have to create a type safe JSON version of the same -- pointless double duty...PHP, Python, Groovy, Ruby, etc. win this particular battle.
I am, BTW, completely playing devil's advocate here ;-), Scala's my daily bread; PHP, wow, I did some horrible things [shudder]
That's true about JSON - it can be quite tedious if you have to write JSON reads and writes for things like JSON validation. But Play can autogenerate the reads/writes combinators for cases where validation isn't needed, so it ends up being as simple as putting a JsonFormatter in your companion object for a case class - 1 line. Play (and Jerkson) usually knows what to do with it, assuming all nested classes have json formatters in their companion objects, too.
I am just glad to be done with PHP.
Agreed, Scala JSON libs are taking the a lot of the boilerplate pain away, but still not quite at the foo.toJson stage.
shhhh, this is, you know, a PHP thread ;-)
In PHP cycles are slightly faster, but Scala lets you do away with lot less cycles. Not only because of awesome library, but also because excellent IDE support with instant type-checking.
heh, that's a stretch, perhaps compared to 3 years ago the IDE story in Scala is all roses. It's improved with time, but I still get arggghhh inducing moments where a given source file turns into a sea of red Xs despite SBT compiling the code just fine. Often an ./eclipse -clean is the only way to right the ship.
Perhaps IntelliJ provides a different experience (although I've heard there are issues with the Scala plugin there as well).
IntelliJ IDEA provides a different experience. I tried the eclipse plugin a month ago - much better than it was 2 years ago, but still far behind Idea. Also, keep in mind, we're comparing it to PHP and not Java.