Abstract: We describe in this paper an effective code generation scheme for a declarative data-parallel language targeted towards sequential, vector or SIMD architectures. The code generation is produced from the declarative data-parallel language 8 1/2, a language that relies on the notions of stream and collection in a high-level declarative framework. We first describe the language and its specificities focusing on data-parallelism. Then we present two optimizations for the generated code: the sharing of common control expressions and the optimization of delay copies. Next, we give some elements for the evaluation of the generated code. As a conclusion, we recall the overall effectiveness of the execution scheme and draw some plans for the future.