c2nim is a tool to translate Ansi C code to Nimrod. The output is human-readable Nimrod code that is meant to be tweaked by hand after the translation process. c2nim is no real compiler!
c2nim is preliminary meant to translate C header files. Because of this, the preprocessor is part of the parser. For example:
#define abc 123
#define xyz 789
Is translated into:
const
abc* = 123
xyz* = 789
c2nim is meant to translate fragments of C code and thus does not follow include files. c2nim cannot parse all of Ansi C and many constructs cannot be represented in Nimrod: for example duff's device cannot be translated to Nimrod.