This is the homepage of Peter Alexander. I am currently at Facebook working on AR/VR. Any opinions are my own.

Recent Posts

• Single-Threaded Parallelism
• unique_ptr Type Erasure
• The Condenser Part 1
• Cube Vertex Numbering
• Range-Based Graph Search in D

Links

Scoped Imports in D

One of the nice things about the D programming language is that it has very convenient syntax for conditional compilation. For example, suppose you want to print out some useful info in debug builds. You just use:

debug writeln("Value of x is ", x);

One problem that I constantly run into in cases like this is that I haven’t imported std.stdio, so I have to go right up to the top of the file, add debug import std.stdio;, back down again, and continue. Sigh.

Not so fast! D has scoped imports, so you can put the import std.stdio; right where you need it.

void main(string[] args)
{
  debug import std.stdio;
  debug writeln(args);
  // ...
}

It’s the little things like this that make D so pleasant to use.