Absolutely concur. Build times are an issue, support is a problem, and I've fallen out of love with a lot of the "magic" you get from Crystal and Ruby. I'll take explicit imports over a globally shared namespace any day.
I've been using Crystal for some 6 years now and it's still my favorite language. It definitely has issues; it's not perfect, but it really hits a good balance between being a fast language with nice features and encouraging the "joy of programming" that Matz is all about. I would love to see it gain popularity eventually.
Care to explain more? Having been using Ruby for about 8 years and Crystal for about 4, they actually have an extremely similar syntax and are also semantically very close. To the point where many Ruby scripts are completely valid Crystal, or at the very least require only a few changes.
I do think that people trying to compare Crystal to Ruby kind of miss the point though. Ruby as an interpreted language, even optimized with JIT compilation, will never match the performance you can get out of a true compiled language. By the same token, Crystal as a compiled language will never be as quick to develop with since you have to wait for your code to compile after each change.
> Care to explain more? Having been using Ruby for about 8 years and Crystal for about 4, they actually have an extremely similar syntax and are also semantically very close. To the point where many Ruby scripts are completely valid Crystal, or at the very least require only a few changes.
It doesn't have Kernel#eval. It doesn't have Kernel#send. It doesn't have Kernel#binding. It doesn't has Proc#binding. It doesn't have Kernel#instance_variable_get/set. It doesn't have Binding#local_variable_get/set. It doesn't have BasicObject#method_missing. It doesn't have BasicObject#instance_eval. I could go on. All these methods have extreme far reaching non-local implications on the semantic model and practical performance, and specifically defeat many conventional optimisations.
> To the point where many Ruby scripts are completely valid Crystal, or at the very least require only a few changes.
You can't even load most of the Ruby standard library without these methods!
And it doesn't matter if you use them or not. They're still there and they impact semantics and performance because the fact that you can use them affects performance. You can't even speculate against most of them as they're so non-local.
Rails and the rest of the mainstream Ruby ecosystem fundamentally depend on them.
> and are also semantically very close
Sorry I super disagree with this. They look similar. Dig into it just below the surface? Start to model it formally? Not at all. Method dispatch, which is everything in Ruby, isn't even close.
(Again, Crystal's great as its own thing, it's just not similar to Ruby's semantics. If you don't need Ruby's semantics or you can replicate them at compile time then maybe it's perfect for you.)
>Sorry I super disagree with this. They look similar. Dig into it just below the surface? Start to model it formally? Not at all.
I think you're missing the point. If 90% of Ruby code works in Crystal unmodified (even if it's because the standard library had to be rewritten from scratch), then the programmer experience may well be quite similar, regardless of how fundamentally different they are if you model them formally.
Are Newtonian mechanics and Einstein's theory of general relativity "similar"? If you model them formally, they look nothing alike. But in 99% of practical situations in every day life, and even in the most precise experiments we could conduct for hundreds of years, they're so similar we can't tell the difference.
That was an example, I was trying to offer chrisseaton a different notion of "similarity".
Another example: if 0% of Ruby code works in Crystal unmodified, but for 90% of code the transformation was extremely simple and mechanical like using curly braces {...} instead of begin...end and prepending $ to all variable names like Bash and PHP, they would still feel extremely similar in practice, albeit obviously less similar than the above example.
By contrast, Java and JavaScript are widely described as having very similar syntax, but it is rare to translate code from one to the other without require fundamental rethinking, because the relationship between JS objects, functions, and prototypes is so different from between Java objects, methods, and classes.
Depends on how you count. On a application level, no. On a class level, also no. On a method level, no but we are getting close. On a row level, possibly. On a token level, definitely.
Agreed. Crystal looks like it has many positive characteristics, but having similar syntax has nothing to do with having similar semantics. Without constructs like missing_method, you cannot run practically any of the Ruby ecosystem libraries, including everything involving Rails.
Java and C also share a similar syntax, but that does not make that you can easily swap one for the other.
To be fair, method_missing has caused more nightmares and problems with debugging than probably any other feature in Ruby. I actively avoid using it, and even the Rails team has massively dialed back on its use in their libraries over the years...
I find this quite amusing because method_missing? has always been the difference between 'true' OO languages Smalltalk/Ruby and pseudo-OO language like C++; with the implication that true OO is better than pseudo OO for the ones making such distinction..
There has never been a "true" OO language. And if it there was, Smalltalk was not it. Alan Kay did coin the term, but Simula existed long before Smalltalk. The tree of languages that include C++, Java, and C# can be traced back to Simula while Smalltalk inspired Ruby. There is a distinct camp of "statically typed OO" (Simula and its children) and "dynamically typed OO" (Smalltalk and its children).
Yet none of this is the one true OO. All of it remains a way of describing a human mode of expression, and so is rightly subjective.
Programming Paradigms and Beyond, Shriram Krishnamurthi and Kathi Fisler:
OO is a widely-used term chock-full of ambiguity. At its foundation, OO depends on objects, which are values that combine data and procedures. The data are usually hidden (“encapsulated”) from the outside world and accessible only to those procedures. These procedures have one special argument, whose hidden data they can access, and are hence called methods, which are invoked through dynamic dispatch. This muchseems to be common to all OO languages, but beyond this they differ widely:
* Most OO languages have one distinguished object that methods depend on, but some instead have multimethods, which can dispatch on many objects at a time.
* Some OO languages have a notion of a class, which is a template for making objects. In these languages, it is vital for programmers to understand the class-object distinction, and many students struggle with it (Eckerdal & Thune, 2005). However, many languages considered OO do nothave classes. The presence or absence of classes leads to very different programming patterns.
* Most OO languages have a notion of inheritance, wherein an object can refer to some other entity to provide default behavior. However, there are huge variationsin inheritance: is the other entity a class or another (prototypical) object? Can it refer to only one entity (single-inheritance) or to many (multiple-inheritance), and if the latter, how are ambiguities resolved? Is what it refers to fixed or can it change as the program runs?
* Some OO languages have types, and the role of types in determining program behavior can be subtle and can vary quite a bit across languages.
* Even though many OO aficionados take it as a given that objects should be built atop imperative state, it is not clear that one of the creators of OO, Alan Kay, intended that: “the small scale [motivation for OOP] was to find a more flexible version of assignment, and then to try to eliminate it altogether”; “[g]enerally, we don’t want the programmer to be messing around with state” (Kay, 1993).
In general, all these variations in behavior tend to get grouped together as OO, even though they lead to significantly different language designs and corresponding behaviors, and are not even exclusive to it (e.g., functional closures also encapsulate data). Thus, a phrase like “objects-first” (sec. 6.1)can in principle mean dozens of wildly different curricular structures, though in practice it seems to refers to curricula built around objects as found in Java.
FWIW, Crystal does have compile-time method_missing. Which obviously is less powerful than the runtime variant, but it is still possible to get fairly far in many practical usages.
To dig into method_missing a bit more: when you call a non-existent ruby method on any object it has to check for and run a method called method_missing, which can contain arbitrarily complex code, on the object itself as well as every class in the inheritance hierarchy. Because ruby is a dynamic language with dynamic dispatch, you can't easily precompute the results of doing this.
Yeah how fast is that compiler? If it's just another compiled language (rather than the kind of wicked fast compiled language like Go), my enthusiasm will be dampened...
If it has reasonable incremental compilation, it can take a few seconds to compile.
With good code structure, I see large Java projects compile small changes in seconds, even though compiling Java used to be a hog. You don't often rebuild from scratch during development, do you?
I often switch between feature branches, when working on more than one project in a repo with multiple related modules. If there's a change near the top of that dependency graph, I'm forced to not exactly rebuild from scratch, but still to rebuild quite a lot.
Right now I'm at the very same situation. Yes, it is frustrating. This is why things close to the top of the dependency graph should be small, well-tested, and rarely need changes. But when you still need to troubleshoot them, there's no way around recompiling a lot of stuff if you want these static guarantees :(
In my case it's not even a language proper; I was using JavaScript which gives you near-zero static guarantees.
I was fixing an issue in one common library; properly testing changes required rebuilding and restarting a number of containers. Unit tests only tell you so much; you need proper integration tests to see how certain things interact.
If I were used a statically typechecked language (e.g. TypeScript), I could have eliminated 50%, or maybe 75% of the testing, because the compiler would check things for me before runtime. It would be drastically faster to localize and fix the bug even if the compilation increased build times 10x.
Often I do because that's what CI does. This is pretty normal.
But the point is having a different view of what compilation means in the developer's workflow as a language designer. Having the engineer have to think about how to organize the code for the compiler is bad design unless that organization is built into the compiler. The compiler should reject programs that are not organized for optimal compilation. And the organization required at least does not impede understanding of the code (best if it improves it). This is Go's design imprimatur and it's critically important to the success of Go.
FWIW, I see large Java projects compile small changes take minutes to compile, even using hot-reload tools.
Figwheel in Clojure is not like this, however: they're doing something right there.
However you frame it, compile times are going to be longer the more static guarantees you need to check, and the longer the more dependencies a particular code change affects.
Making your code low-coupling if equally beneficial for the compiler and for the human to reason about the code. Hence modularization, limiting the visibility of parts, etc.
OTOH there are situations when you have to have a common interface which is used across the board. Imagine Java's `List` or `CharSequence`. If you touch it, you have to recompile all the innumerable uses of it. So the more pervasive the dependency is, the smaller and simpler and more fine-grained it should be. Java's `List` does not do a hugely good job in the compactness department; it's pretty stable, though. You want the same trait from your most foundational interfaces.
