I used ELI in 1993 to construct a compiler for a language called Fourier (Ada like) for a contract with the Canadian Government. It was the coolest compiler writing experience ever. Operator overloading was a breeze, type analysis, semantics, even command line options, etc. were all a breeze. Imagine using space age tech to write a compiler while all these people around telling that YACC or BISON is a --ehm-- compiler generator. No they are not. They are parser generators. I definitely agree: Eli: Translator Construction Made Easy.