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Recognizing that name binding is often done in an ad-hoc manner, Visser and his colleagues introduced scope graphs as a uniform representation of a program's static binding structure along with a generic means for interrogating that representation to resolve name references to their declarations. A challenge arises in scheduling the construction and querying actions so that a name resolution is not performed before all requisite information for that resolution is added to the scope graph. Visser et al. introduced a notion of weakly critical edges to constrain the order in which name resolution queries are performed to a correct one, but this has been found to be somewhat restrictive. Visser et al. also introduced Statix, a constraint solving language for scope graph-based name resolution. We show that specifications written in an annotated version of Statix can be translated into reference attribute grammars, and that the order in which equations are solved under demand driven evaluation provides a valid order for solving constraints in Statix. This formalizes what has been folklore in the attribute grammar community for some time, that scope graphs are naturally specified in reference attributes grammars. 

It is not uncommon to design a programming language as a core language with additional features that define some semantic analyses, but delegate others to their translation to the core. Many analyses require contextual information, such as a typing environment. When this is the same for a term under a new feature and under that feature’s core translation, then the term (and computations over it) can be shared, with context provided by the translation. This avoids redundant, and sometimes exponential computations. This paper brings sharing of terms and specification of context to forwarding, a language extensibility mechanism in attribute grammars. Here context is defined by equations for inherited attributes that provide (the same) values to shared trees. Applying these techniques to the ableC extensible C compiler replaced around 80% of the cases in which tree sharing was achieved by a crude mechanism that prevented sharing context specifications and limited language extensibility. It also replaced all cases in which this mechanism was used to avoid exponential computations and allowed the removal of many, now unneeded, inherited attribute equations.