On Friday, 18 October 2013 at 06:13:38 UTC, DDD wrote:
I'm learning D. I'm curious about surprises I may get. I
typically use C++, C# and javascript
Some stuff from the top of my head. Remember that you're asking
for gotchas and
surprises rather than the nice features of D :)
* D has built-in support for three different character types.
UTF-8, 16 and 32.
The default, char and string, is UTF-8. This means .length
gives the number
of bytes, not necessarily the number of symbols.
* Private protection is private to the module, not to the type.
This means a private class method can be called from anywhere
in the module.
* Array slices are great, but they require some understanding on
how the
underlying runtime handles them. See the array slice tutorial.
* D has compile-time reflection rather than runtime. There are
some features
related to runtime reflection, but it's quite minimal. It's
possible to get
runtime reflection by using compile-time reflection though.
* Templates in D is actually useful, so use them :)
For example, in C#, generic type constraints isn't part of the
signature, so
you cannot overload generic functions. In D, this is not a
problem.
You can look at std.typecons to get a glimse of how powerful D
is (warning:
it still blows my mind, so it's not for the faint of hart, and
you should
probably delay this - most D code is actually very nice and
readable and not
at all this complex).
* D doesn't have a preprocessor. You can solve much of the same
stuff by using
string mixins, template mixins and debug and version
statements. Note that
version statements is quite minimal and doesn't support stuff
like && or ||
by design.
* The GC isn't as fast as in other languages (yet?), so if you
are experiencing
performance problems in a tight loop, try disabling the GC
during that loop.
* Not a gotcha, but you should look into D specific features like
transitive
const/immutable, pure, nothrow, safe, DbC, unittest, -cov,
final switch,
scope guards, templates, foreach etc. These change the way you
code and is
idiomatic D, so it's nice to learn them early on.
