Dunno if he mentions it on the video but in the FP community they refer to this dicoromy as the "Expression Problem" http://c2.com/cgi/wiki?ExpressionProblem h

Dunno if he mentions it on the video but in the FP community they refer to this dicoromy as the "Expression Problem" http://c2.com/cgi/wiki?ExpressionProblem http://c2.com/cgi/wiki?ExpressionProblem The name comes from choosing the best way to represent a datatype for expressions in a programming language. The pattern-matching approach makes it easy to define new functions on top of ASTs and the OO-approach makes it easy to add new kinds of node to the tree but its really hard to make a system that is easy to extend in both directions.