Slashdot Mirror
The D Programming Language, Version 1.0
penguinblotter writes in a journal article: "Soon, Walter Bright is scheduled to release version 1.0 of the D Programming Language. D is a systems programming language. Its focus is on combining the power and high performance of C and C++ with the programmer productivity of modern languages like Ruby and Python. Special attention is given to the needs of quality assurance, documentation, management, portability and reliability. D has appeared on Slashdot a few times before, and Walter has continued to add more and more features. Most Slashdot community comments in these articles have been offered on feature X or spec Y without reading through the extensive D newsgroup archives. It has been here over the past seven years where extremely gifted and experienced programmers hashed out discussions and arrived at excellent implementations of all the ideas discussed." Read on for the rest of penguinblotter's writeup.
For those with a C/C++ background, D offers:
From D's creator:
For me, it's hard to pinpoint any particular feature or two. It's the combination of features that makes the cake, not the sugar, flour or baking powder. So,
For those with a C/C++ background, D offers:
- native code speed
- extremely fast compilation times
- garbage collection (although you can manage your own memory if you want)
- OOP - by reference only, easy initialization, always virtual
- cleaner template metaprogramming syntax, more powerful templates, as well
- built-in dynamic and associative arrays, array slicing
- versioning (no preprocessor madness)
- link-compatibility with C
- nested functions
- class delegates / function pointers
- module system
- similar syntax
- No virtual machine or interpreter
- built-in unit testing and design-by-contract
From D's creator:
For me, it's hard to pinpoint any particular feature or two. It's the combination of features that makes the cake, not the sugar, flour or baking powder. So,
- My programs come together faster and have fewer bugs.
- Once written, the programs are easier to modify.
- I can do (1) and (2) without giving up performance.
From the compared to C/C++ list:
* native code speed
As opposed to C/C++.
* extremely fast compilation times
Point granted (compared with most C++ compilers).
* garbage collection (although you can manage your own memory if you want)
Point granted, even though C and C++ arguably have optional garbage collection as well (if you link to the right library).
* OOP - by reference only, easy initialization, always virtual
Only value semantic? Meyer had to accept that value semantic was useful, and add it to Eiffel eventually, and C# added it over Java.
And no way to specify that a function will always be the one specific. Good luck doing any kind of reasoning there.
Bragging about missing features, that are essential to many tasks.
* cleaner template metaprogramming syntax, more powerful templates, as well
*More* powerful templates? The usual complaint is that C++ templates are too powerful (a Turing-equivalent compile time language).
* built-in dynamic and associative arrays, array slicing
Not exactly a recommendation that the core language apparently is so weak that these can't be put into libraries.
* versioning (no preprocessor madness)
I'm guessing he meant variants here, the preprocessor is often used for variants, rarely for versioning.
* link-compatibility with C
Which C and C++ of course lacks?
* nested functions
Point.
* class delegates / function pointers
Obviously both C and C++ have function pointers.
* module system
More preprecessor replacement here.
The C#/Java list:
* similar syntax
But totally different from C++?
* No virtual machine or interpreter
You can compile Java and C# to native code as well, so this is just another case of bragging about a missing feature.
* built-in unit testing and design-by-contract
I'm a C++ programmer, and this is by far the most interesting aspect of the D language (and of Eiffel before that). Don't know why it should be in the Java/C# list.
Exactly. There's already Fortran and COBOL, everything else is superfluous.
Seriously though, why don't we need another programming language? It's not like we only get a finite number of them. We're not going to run out of space or anything.
If it doesn't interest you, don't use it.
Maybe not
I'm sure D is a lovely language, but it just seems like another incremental change over C++, like Java and C# before it, and like both of those languages what it's lost and the opportunities it misses are as telling as the little tweaks it makes to improve things.
No-one has yet been successful, IMHO, in developing a really good industrial programming language. Those that make it tend to be pragmatic, practical tools like C and Perl and FORTRAN and COBOL. To be sure, each of these has many widely-acknowledged weaknesses, but the overall balance between those weaknesses and what you could get done using the language was right.
I can increasingly see why some well-known programming language designers shy away from feature comparison ticklists. I think it's because as soon as you go down this route, you bias the comparison so much that it's meaningless. For example, consider the first checklist cited in the Slashdot write-up. (I note in passing that this is a wiki, and may change before you read this.) Here are some of the "yes or no" (almost) categories:
Templates or executable macros No difference in expressive power is acknowledged between LISP macros and C++ templates. Thread synchronization primitives With no reference to how expressive they are, and how powerful the idioms supported by them? This one is really telling, IMHO, because I don't believe the future lies in classical thread sync and locking primitives. The whole approach is just too prone to deadlocks and race conditions to withstand the heavily parallel future that multicore chips are starting to bring into the mainstream. When you have ideas like pure function programming languages, operating in a world without side-effects where explicit locking isn't necessary, or interesting ideas for inter-thread communication such as those in Erlang, another variation on built-in pthreads just isn't worth much. Enumeration So again, we acknowledge no difference between simple and low-level enumerations such as those in C, and concepts such as disjunctive types and pattern-matching that are very powerful, remarkably elegant, and mainstream in certain families of programming language. Again, this is just papering over a gap, where other languages operate on an entirely different level. Long double floating point (80bit) This is just desperation. Pretty much no-one uses 80-bit floating point arithmetic IME (and yes, I do work in the field). The portability hazards and lack of true support from almost every mainstream architecture make them almost irrelevant, except perhaps for a few very small niches. Lexical Closures Another telling omission: the power of all those neat functional programming features is dramatically reduced when you can't construct functions on-the-fly.On top of all of this, the feature lists invariably gloss over some less concrete things that are nevertheless very important to systems programming languages. How portable is D? How many production-quality implementations are available? Is the language standardised or under the control of a single, commercial body? How much backing is there behind the language in the commercial development space; do others write libraries specifically for this language, or is it reduced to using C-style interfaces at the lowest levels anyway, and what impact does this have on the usefulness of features like DBC, exceptions, and so on? Does the language have an active hobbyist/volunteer community supporting it?
I could go on, but I don't want this post to disappear into the oblivion any more than it already will. Although I'm deliberately focussing on criticising in this post, as I often do with D, I keep an open mind and will happily engage in debate with others, or even be proved wrong by people who have found D to have compelling advantages. So go ahead, D advocates, start your counter-arguments here...
If you disagree, post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like.
My feeling is that languages shouldn't try to satisfy all possible needs. Rather, we should have small and clean languages, use the right tool for each job, and combine code libraries from different languages when needed. (I regularly use 3-6 languages in a single project and my life is much happier for it.)
(Legacy support is critically important too, but it is vastly better to provide legacy support by providing ways to call older languages, especially the lingua franca of C, rather than demanding that the new language be a superset of the old. I still call numerical libraries written in pre-1970 Fortran, but that doesn't mean I have to write my code in a Fortran derivative.)
If a thing is not diminished by being shared, it is not rightly owned if it is only owned & not shared. S. Augustine
0XA1_2_C35_4_5_6_5P6_Li
Give up? Why, it's an imaginary real. Yes, you read that right. Oh, and I specified it in hexadecimal, just to prove I can. And I threw in some underscores because you're allowed to do that too. Have you guessed what an imaginary real is yet? This is supposed to be the "simpler C/C++ replacement."
A good language strives to find a few constructs that solve multiple problems. A bad language takes the kitchen sink approach. C and C++ are not good languages, but wide deployment and support make them useful anyways. D does not have that, but the designers do have the luxury of learning from the mistakes of the past. So what the hell is their excuse?