Programming Languages: Concepts and Implementation

15.2 Relationship of Concepts

Figure 15.1 casts some of the language concepts we studied in relationship to each other. In particular, a solid directed arrow indicates that the target concept relies only on the presence of the source concept; a dotted directed arrow indicates that the target concept relies partially on the presence of the source concept. If a language supports all of the concepts emanating from the dotted incoming edges of some node, then it can support the concept represented by that node. For instance, the two dotted arrows into the recursion node express the result of the fixed-point Y combinator: Support for recursion can be built into any language that supports first-class and λ/anonymous functions. However, generators/iterators ...