The Expression Problem Export

@misc{citeulike:157592, abstract = {The Expression Problem is a new name for an old problem. The goal is to define a datatype by cases, where one can add new cases to the datatype and new functions over the datatype, without recompiling existing code, and while retaining static type safety (e.g., no casts). For the concrete example, we take expressions as the data type, begin with one case (constants) and one function (evaluators), then add one more construct (plus) and one more function (conversion to a string). Whether a language can solve the Expression Problem is a salient indicator of its capacity for expression. One can think of cases as rows and functions as columns in a table. In a functional language, the rows are fixed (cases in a datatype declaration) but it is easy to add new columns (functions). In an object-oriented language, the columns are fixed (methods in a class declaration) but it is easy to add new rows (subclasses). We want to make it easy to add either rows or columns.}, author = {Wadler, Philip}, citeulike-article-id = {157592}, citeulike-linkout-0 = {http://www.cse.ohio-state.edu/~gb/cis888.07g/java-genericity/20}, howpublished = {Mailing list}, journal = {java-genericity Mailing List}, keywords = {expression-problem, extensibility}, month = {November}, posted-at = {2005-04-10 15:58:38}, priority = {2}, title = {The Expression Problem}, url = {http://www.cse.ohio-state.edu/~gb/cis888.07g/java-genericity/20}, year = {1998} }

TY - ELEC ID - citeulike:157592 L3 - citeulike-article-id:157592 N2 - The Expression Problem is a new name for an old problem. The goal is to define a datatype by cases, where one can add new cases to the datatype and new functions over the datatype, without recompiling existing code, and while retaining static type safety (e.g., no casts). For the concrete example, we take expressions as the data type, begin with one case (constants) and one function (evaluators), then add one more construct (plus) and one more function (conversion to a string). Whether a language can solve the Expression Problem is a salient indicator of its capacity for expression. One can think of cases as rows and functions as columns in a table. In a functional language, the rows are fixed (cases in a datatype declaration) but it is easy to add new columns (functions). In an object-oriented language, the columns are fixed (methods in a class declaration) but it is easy to add new rows (subclasses). We want to make it easy to add either rows or columns. JF - java-genericity Mailing List TI - The Expression Problem KW - expression-problem KW - extensibility AU - Wadler, Philip PY - 1998/11/12/ UR - http://www.cse.ohio-state.edu/~gb/cis888.07g/java-genericity/20 ER -