> The answer is that bright Yang – iteration – has its own dark side, its own Yin. The presence of side effects (among other things) makes the programs hard to

> The answer is that bright Yang – iteration – has its own dark side, its own Yin. The presence of side effects (among other things) makes the programs hard to understand, verify, or modify. There are no "side-effects", only effects. The question is, "Have you planned and implemented their cascades according to the design requirements?" Change is all that matters in our digital logic manipulation business, and the only bottom-line results of any consequence are the bits that have been changed, plus the where, how, and why they did. The overall theme of the article presents an interesting and well-considered perspective, but my already knowing that all recursive algorithms have an equivalent iterative version is enough for me to be more interested in the traversals than the mechanism used to perform them. I want my data to flow in specifically precise ways. Choosing the proper tooling is an essential part of a project's work's earliest stages, and different folks succeed using different tools. [addendum: learned a cool new word today: eduction := the act of drawing out or bringing into view]