When comparing D vs Xtend, the Slant community recommends D for most people. In the question“What is the best programming language to learn first?” D is ranked 28th while Xtend is ranked 68th. The most important reason people chose D is:
With few exceptions, D will either compile C code to work exactly as when compiled as C, or it won't compile - it won't quietly change the semantics of C code and give unexpected results. This means that D contains an improved C, as it fails compilation where type safety is missing in C. This allows learning the same machine operations available in C and other low-level languages.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Has an improved C subset
With few exceptions, D will either compile C code to work exactly as when compiled as C, or it won't compile - it won't quietly change the semantics of C code and give unexpected results. This means that D contains an improved C, as it fails compilation where type safety is missing in C.
This allows learning the same machine operations available in C and other low-level languages.
Pro Easy to read and understand code
Pro Doesn't force you to deal with memory management
When you're just starting out, dealing with manual memory management and its bugs is a huge pain! D is garbage collected by default, which removes a huge class of things that could go wrong. And later on, if you decide you don't want or need the GC, you can turn it off.
Pro Very fast compilation
D is usually up to 10 times faster than C++. Having a language that compiles this fast means that you are free to write highly optimized code because of the relatively low cost of experimentation.
Pro Unit testing built-in
D provides unittest blocks to insert code that verifies functions preform their expected behavior and document edge cases. Since these are enabled with a compiler switch, there is no need to teach new programmers how to install new libraries and import modules, instead training on test driven design can start from the very first function.
Pro Provides a powerful data structure on top of C's arrays called slices
D provides a structure that builds on C's arrays called slices. A slice is a segment of an array that tracks the pointer and the length of the segment.
Slices are extremely powerful because they combine the protection of knowing the length of the data with the garbage collector that manages the memory backing that data, thus avoiding most memory corruption issues.
Pro It's a state-of-art evolution of C
Pro Static with type inference
For a new user adding types can feel tedious, and takes focus off the meaning of the code, but they are also important for checking logic. D provides static types, and a good system to infer types, so types are checked when calling functions, but do not need to be specified everywhere, making it feel more dynamic.
Pro Provable purity and immutability
The compiler can check that functions don't have side effects, extremely important for functional programming in concurrent scenarios, and can check immutability.
Therefore, the compiler will prove that your programs are functionally pure and respect immutable data, if you want it to.
Pro Compile-time Function Execution
Pro Built-in Unicode support
Pro Industrial quality
Pro Asynchronous I/O that doesn’t get in your way
Because all types can be treated as objects, all files can call functions in the same manner -- even stdin
and stdout
. stdout.writeln();
stdin.readln();
file.writeln();
file.readln();
Pro Easy to integrate with C and C++
D practically has the same memory structure as C and C++; all D does it build a structure around that. The entire C standard library is accessible at no cost (syntactic or speed) and it's being worked on allowing the same for the C++ standard library.
Pro Designed for concurrency and parallelism
Supports first-class functionality for both concurrency and parallelism, offered as part of the standard library.
Pro Supports calling functions from types in an object-oriented manner.
if (exists(file)) {}
may be written as if (file.exists) {}.
writeln(file);
may be written as file.writeln();
isDivisibleBy(10, 2);
may be written as 10.isDivisibleBy(2);
writeln(isEven(add(5, 5)));
may be written as 5.add(5).isEven().writeln();
Pro Ruby-like syntactic conveniences
Lambdas are written like Smalltalk's blocks. If it's the last argument, it can go after the parentheses like Ruby's blocks. Parentheses on method calls are optional.
Pro Type inference
It uses Java's static type system, but you don't have to declare the type of everything all the time, since the Xtend compiler can usually figure it out. This also dramatically cuts down on Java's infamous verbosity.
Pro Code runs just as fast as Java
Because Xtend relies heavily on JDK and Android classes, it runs just as fast as native Java code.
Pro Easy to switch back to Java
Xtend is a low-risk option. Because it compiles to human-readable Java, if you decide you don't like it for your project, you can just switch back to Java without losing your work.
Pro Extend even library classes with new methods
This is where it gets its name. You can open classes and add new methods, kind of like Ruby. (Of course this has to be compiled to Java, so really it lives in a kind of helper class.)
Pro Succint
Uses functional features ,which are very concise and idiomatic. Plus it has annotations, which cuts down on the Java boilerplate.
Pro Better defaults than Java
Methods are public if you don't specify, and fields are private. Locals declared with val
in Xtend are final
in Java. This dramatically cuts down on Java's infamous verbosity.
Cons
Con Poor adoption even after many years of existence
There's a widely accepted perception of D as a language that has been poorly adopted. Since adoption is driven by perception this becomes a fact. So managers and engineers start becoming nervous in adopting a language that has such a perception among the community and that has been so unsuccessful for so long.
Con Failed at becoming alternative to C or C++
Almost as confused and complicated as C++, but without the popularity and widespread corporate usage. Also failed at becoming a good cross-platform GUI application development language like Object Pascal. Many missed past opportunities, and now newer languages are better alternatives.
Con Lack of vision
D is community-driven and lacks the support of any large corporation. While this increases the amount of talent and engineering abilities of the people working on D, it also brings a severe lack of charisma, leadership and vision.
Con Garbage Collection
Memory is not managed directly.
Con All the downsides of garbage collection without any of its benefits
When D decided to implement garbage collection it instantly alienated a large community of developers (C and C++ programmers). For them, the official policy has been: "Don't want garbage collection? Use D with RAII or manual management style!".
While true, it's also absolutely pointless because there's little to none support for alternate memory management styles in the standard library, which means that a new user will have to start with a language that is stripped down of the core infrastructure.
On the other hand, for those people who want to use garbage collection, the implementation of it is lackluster.
Con Difficult to configure in Android Studio
Con Slower compilation
Unlike most JVM languages, Xtend compiles to Java rather than directly to JVM bytecode. So you have to compile everything four times for Android: from Xtend to Java, from Java to JVM bytecode (.class files), from .class to .dex bytecode, and then AOT compilation from .dex to native ARM upon installation. This can really slow down development and testing vs a more interactive language like Clojure.