Xcode are the included Developer Tools, for Mac OS X 10.3 "Panther" and above.
GDC is a frontend to the regular GCC compiler, for the D programming language.
It is possible to used the "Xcode" IDE for writing, compiling and debugging D programs.
This is done by installing the GDC compiler package, and adding a few custom build rules.
Note: this information is for Xcode 1.5 (Panther), and hasn't been updated for Xcode 2.4 (Tiger) yet
For Tiger and Leopard, use the D for Xcode plugin instead.
D source code files are syntax-colored in the builtin text editor. (using a "tweaked" C++ template)
For Xcode 1.x you need a custom build rule, to compile all the *.d files using the gdc compiler.
Compile errors are highlighted in the D source code file, by line number. (using the GDC compiler)
As usual, you can find the detailed compilation errors and compiler output in the build log window.
The corresponding D source code are highlighted in the builtin debugger. (using the GDB debugger)
There is no name demangling for D yet, so you will get the "mangled" name in the debugger listings.
D language support for Xcode (16 KB, installs the D file specification, syntax coloring and icon)
D demangler utility - like std.demangle (4 KB, C source for a D name demangler utility program)
GDB Patches - GDB Patches for debugging in D