How to Deforest in Accumulative Parameters?

Software engineering has to reconcile modularity with ee-ciency. One way to grapple with this dilemma is to automatically transform a modular-speciied program into an eecient-implementable one. This is the aim of deforestation transformations which get rid of intermediate data structures constructions that appear when two functions are composed. Nevertheless, existing functional methods cannot defor-est non-trivial intermediate constructions that are processed by symbolic composition. This new deforestation technique is based on the descrip-tional composition dedicated to attribute grammars. In this paper, we present the symbolic composition, we outline its counterpart in terms of classical deforestation methods and we sketch a way to embed it in a functional framework.