CTFE, string mixins & code generation

[Jan Hönig]

I am looking for a detailed explanation or showcase regarding 
CTFE and string mixins.
I want to play with D a little bit regarding code generation.
I would like to have a pseudo-AST, consisting of a few classes, 
to represent some calculation. Think of a loop, some statements, 
and expressions.

To do that, I want to be certain that this AST can be computed 
and generated during compile-time, with CTFE and string mixins.

Are there limitations regarding CTFE (GC, global variables, 
static variables, templates, ....)?
Are there any limitations regarding string mixins (which are not 
already included int the CTFE limitations)?