On Thu, Oct 22, 2009 at 1:29 PM, jlist9 <jli...@gmail.com> wrote: > > Hi David, > > Appreciate your reply. It's definitely helpful in clearing some of my > thoughts, > as well as in my process of learning Scala down the road. I also think your > book is very well paced and organization of the content is well thought > out. > Great job! >
Thanks! > > I'd like to explain a little bit where my frustration is coming from > (and I don't > want to waste people's time reading further for those who aren't > interested.) > > I come from Java and Python background. When learning these two languages > I didn't have a problem with the syntax. I think Java's syntax is well > defined > although verbose, and Python's is clear and concise. There is a small > number > of operators and data types and it's pretty clear which is for what > purpose. > "Zen of Python" says it well: > > "There should be one-- and preferably only one --obvious way to do it." > Yeah... that's a big problem for Scala. If Scala were CAL ( http://groups.google.com/group/cal_language) there'd be fewer ways to do stuff. But Scala straddles Function and OO, Java libraries and Scala libraries, etc. Personally (in my "library consumer mode"), I use very little of Scala. I use List and Map and some XML stuff. I use case classes and pattern matching. I pass functions as parameters just like String and Long. I use Tuples. I think all that stuff is usable. I think it's consumable. Try using less of the language and libraries and see how it suits you. > > and I think this reflects well in the language design of Python. > > It's also generally discouraged to use too much "black magic" when coding > in Python so that the code is easier to understand and maintain, although > Python, being a powerful dynamic language, is very capable of black magics. > > These two things helped a lot in my learning of Python. It's a much smaller > set of syntax to learn and it can be learned in a very short time, maybe > through > one or two online tutorials. The rest of it is just libraries, which > are very rich > in functionality, but the source code is easy to understand, because of the > small set of clearly defined elements in the language - syntax and > data types, etc.. > > However, I don't feel the same about Scala. In Scala, I often see multiple > ways > of doing the same thing, or very similar things, and this is confusing. > > For example, there are multiple ways of running a program. You can have a > script, or an application. To run an application, you can write an "object" > and > implement the main method, or you can extend Application class and write > the code right in the body of the class. It took me a while to figure out > how > it works. What's wrong with having only one of them? Python only start as a > script and Java only need a main method but either way works. > > Another example is that in some scenarios ( ) and { } are > interchangable in Scala > code, although I haven't figured out in what occasions they are, and > in what occasions > they are not. This puzzles me more because ( ) and { } are the basic > elements > in a language and the language allows such flexible usage of them. Although > I > think there should be a good reason for this but it still struck me as odd. > > In contrast to Python's short list of operators, because operators are > actually functions > in Scala, it's easy for Scala to have a new operator, or have > functions that works > like operators. This is a powerful feature and it is good news for > people who want to > create DSLs. However I think a plethora of operators make code much harder > to > read before people can make it a habit to convert operators as > functions in their mind. > > To summarize, the more I learn Scala the more I realize how powerful > it is. Meanwhile, > I think Scala imposes this mind tweaking that people have to go > through in learning > this language, the difficulty that I didn't feel when I learned > Python, or Java, C or C++. > I like many of the features provided by Scala but I hope some of the > things can be > simplified/demystified to make it easier to pick up and use. > > jlist9 > > On Thu, Oct 22, 2009 at 9:04 AM, David Pollak > <feeder.of.the.be...@gmail.com> wrote: > > I've drafted a couple of different versions of a response to this message > > and they all seem somewhat mean and/or condescending... that is not at > all > > my intent... here's another draft and please read it as acknowledging the > > challenges you are articulating, but suggesting a different perspective > on > > the issue. > > Lisp/Scheme/Clojure is syntactically the simplest language around. Yet, > > when I look at Clojure code, it to a great degree seems complex to me, > even > > though I know it's not. I believe this is because the patterns are > > different than those I've rehearsed through my journey of asm, Basic, C, > > ObjC, C++, Java, Ruby, and Scala. Rehearsing a different paradigm is > part > > of making that paradigm part of you. > > When I studied French in grade school and high school, I > was flummoxed and > > quite angered by gendered nouns. As a native English speaker, a table is > an > > it, not a she (or he.) But fluent French speakers make gendered nouns a > > normal part of the language, and once skilled can use these subtleties > with > > great skill. > > My 2 year learning curve for Scala can be summed up in the first 4 (or > maybe > > 5) chapters of Beginning Scala. I sought to present my painful learning > > curve in < 150 pages that could be reasonably consumed by a Java or Ruby > or > > Python coder in a week or two. Yeah, it still takes a fair amount of > > practice, rehearsal, to be proficient, but if someone had led me down the > > path that I led my readers down, I think my pain-curve would have been > 3-4 > > months, not two years. > > Put a different way, the Programming in Scala folks passed a couple of > > drafts of the first chapters of their book by me early on. I think PinS > is > > a tredmendously awesome work, but I objected strongly to the "show > > imperative first and gently migrate to functional" approach they took. I > > thought it did a significant disservice to their readers. I took the > > opposite approach in BegSca... the second substantive example covers a > broad > > spectrum of functional programming. > > So, getting to some of the substance of your post, as Tim pointed out, > the > > "_" is a running joke in Scala-land. Yep, it's way overloaded. Every > time > > (and this happened at both Scala Lift Offs) Martin tries to justify the > > "_"'s use, people roll their eyes. > > On the other hand, the example that you gave is one of my proudest > moments > > in Lift. Specifically, I think Mapper is a steaming pile of something. > I > > am really dissatisfied with it (although we followed the same paradigm > with > > Record and I'm unhappy with that as well... mostly from the mutability > > standpoint). On the other hand, the graceful way that Mapper deals with > > validators (they are functions and they are declared as a List that can > be > > dynamically generated) is something that I look at and remember it being > the > > first time I really felt like I "got" the power of Scala. When I > developed > > that paradigm, I genuinely felt like Lift was going to be something > > different and better. > > So, I am truly sorry that you and others are struggling with Scala (yeah, > > everyone other than Martin and Adriaan and a few others struggle with > > Scala's type system, but most people didn't get General Relativity early > on > > either) and I hope that we can present materials to you in a way that > helps > > minimize the struggle. > > Thanks for sharing your thoughts and I hope this message has struck the > tone > > I intend it to. > > David > > > > On Wed, Oct 21, 2009 at 10:13 PM, jlist9 <jli...@gmail.com> wrote: > >> > >> override def validations = validPriority _ :: super.validations > >> > >> This is a more of a comment about Scala than one about Lift - this does > >> look cryptic to me. And this is just one of the simpler syntax that > >> confuses > >> people, who are new to the language. And I'm one of them. > > > > Interesting... this is one of the constructs in Lift that I find simple > (and > > almost always have found simple). It's adding a validator to a list of > > validators. Having validators as functions was an early (while my mind > was > > still mostly Java/Ruby) construct that, when I look at it says, "this was > > something that still works." Mapper's general use of mutability, on the > > other hand, is something that very much does not work (although the > > syntactic cost of doing something else is still too high.) > > > >> > >> I understand that you don't have to learn all the tricks/syntax to start > >> coding in Scala but you do have to understand it when you read > >> source code of libraries written by someone with much more advanced > >> language skills. > >> > > > > In this particular case, building an immutable list of of a new element > and > > a prior element and the syntax for turning a method into a function are > both > > very core concepts in Scala (and pretty core in Ruby as well, although > the > > syntax is different). I do not view these as any more advanced than > > overriding methods in Java. > > The Scala skills needed to understand and consume most of Lift's APIs > should > > not be part of the advanced piece of Scala. The advanced piece of Scala > has > > to do with the type system and its interaction with OO. You can see the > > challenges that these advanced pieces of Scala pose to folks in the way > the > > new collections are being re-written. This is the hard stuff in Scala. > > Cons cells, immutable lists, and promoting methods to functions are not > > tough concepts. > > > >> > >> In David's book he says "After more than two years of coding Scala, ... > >> My brain has finally stopped hurting." This sounds like a very high > >> barrier to entry. > > > > Yeah... that was more of a statement about the change in thought > processes. > > I distilled most of the painful concepts into the first 4 chapters of > the > > book. It took a very, very long time to unlearn beans/getters/setter > (this > > was my default way of programming from age 12 to age 42). If the first 4 > > chapters of the book resonate with you, if you can practice them > > comfortably, then you are over the part where my brain hurt a lot. > > To be fair, my brain started hurting when I started coding in Ruby and I > > discovered closures. Ruby's syntax for dealing with closures sucks (a > max > > of one per method call, it may or may not be a method parameter, etc.) > But > > it was a sea change in the way I approached programming. But if you're > > already a Ruby coder, you're familiar with passing functions... much of > my > > painful switch-over is something you've already experienced. > > > >> > >> I'm just wondering why Scala has to be so complicated. > > > > There are two Scalas. The Library Consumer part of Scala which is less > > complex conceptually an syntactically than either Ruby or Java. The > Library > > Producer (types, type bounds, path dependent types, implicits, view > bounds) > > that are complex, but I've tried to shield most of that from the casual > > users of Lift. From a syntax perspective, Scala is less complex that > Java > > and far, far less complex than Ruby (just talk to Charlie Nutter who > > re-implemented Ruby's parser in JRuby.) > > > >> > >> I'm sure a lot > >> of things in Scala have their reasons but at the mean time I also > >> suspect that many of the odd things are there to reduce > >> typing, which is advertised as one of the advantages of this language - > >> conciseness. (I could be very wrong due to my lack of understanding.) > > > > It depends on what strikes you as odd. Please see my next comment. > > > >> > >> If the latter is true, I feel that I'd rather type a little more to make > >> the > >> code easier to read. > > > > Interesting... I find Clojure hard to read. It's mostly because I don't > > have a Lisp/Scheme background and I don't know the common function names > > ("my other car is a cdr"). To me, that's not complexity, > that's rehearsal. > > I had the same problems going from Java to Ruby. The syntax, common > method > > names, etc. were different and needed to be learned (I can't tell you how > > many times I was bitten by not being able to do: "Hello " + 33 > (TypeError: > > can't convert Fixnum into String)... for a dynamic language that ain't so > > dynamic). Ruby's terrifically complex syntax requires year and years to > > master, although most of it is simple enough to pick up in a few weeks. > > Ruby's meta-programming > > > >> > >> Just feeling a little frustrated learning Scala. I think it's much > >> easier learning > >> Java. Not much surprise. Not sure if anyone shares my experience > >> (and opinion, if there is one.) > >> > >> On Wed, Oct 21, 2009 at 3:56 PM, Randinn <rand...@gmail.com> wrote: > >> > > >> > http://localhost3000.de/2009/10/a-quick-glance-at-lift/ > >> > > >> > The site above is a blog post from a Rails developer, he had some good > >> > and bad things to say about Lift and since I do not know enough to > >> > debate with him I thought I'd post it here. > >> > >> > > > > > > > > -- > > Lift, the simply functional web framework http://liftweb.net > > Beginning Scala http://www.apress.com/book/view/1430219890 > > Follow me: http://twitter.com/dpp > > Surf the harmonics > > > > > > > > > > > -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Surf the harmonics --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Lift" group. 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