1. A computer method for generating software development model-to-model transformations from one software program domain having a respective structured hierarchy to a second software program domain, comprising: generating software development model-to-model transformations from a given domain of a software program to a target domain of the software program, at least the given domain having a respective structured hierarchy, by: enabling a user to model and specify a transformation declarative provided by a Model Transformation Authoring Framework (MTAF); in response to the user specified transformation declarative, creating a declarative mapping between a domain specific language modeling software development design of the software program in the given domain and a modeling language modeling software development design of the software program in the target domain, the declarative mapping specifying how the domain specific language of the given domain relates to the modeling language of the target domain; using the declarative mapping, generating a transformation code implementation of transformation from a software development model of the software program in the given domain to a software development model of the software program in the target domain, the generated transformation code being executable to perform a transformation of the domain specific language of the given domain to the modeling language of the target domain, said generating the transformation code implementation including augmenting the transformation code with more transformation logic that is unexpressible in the declarative mapping, wherein the MTAF provides to the user design decisions with respect to specification of the declarative mapping; and outputting instances of models of the software program in the target domain resulting from the performed transformation at runtime.