[mpweiher]

While there is some truth to the author's point, and we can see the effect in in a lot in practice, he makes the mistake of confusing "useful" with "analyzable in FP terms".

This exact point (comprehensibility vs. power) is why Smalltalk is so amazing: it adds a lot of power while at the same time being more comprehensible, not less. That's no small feat, and IMHO one that is both under-appreciated and under-analyzed.

EDIT: Of course, see "The Power of Simplicity" http://www.selflanguage.org/_static/published/self-power.pdf

[Guvante]

He isn't talking about comprehensibility but instead analyzeability. For instance a type system normally improves comprehensibility but sometimes can require rewriting your algorithm in a less clear way, reducing how easy it is to understand. In contract it always improves analyzeability as you can say more about the program without going into details.