Lambda the Ultimate

What facets of a programming system (language, libraries, tools, etc) make it easy to learn and use?

If you were to design from scratch a new programming system, what choices would you make in order to attract users? To what extent would you compromise the design in order to do so?

With Peter's observation that everything good in Computer Science happened during the "Golden Age" freshly in mind, I found Russ Cox's recent article on regular expressions to be enjoyable reading.

This is a tale of two approaches to regular expression matching. One of them is in widespread use in the standard interpreters for many languages, including Perl. The other is used only in a few places, notably most implementations of awk and grep. The two approaches have wildly different performance characteristics ... The trends shown in the graph continue: the Thompson NFA handles a 100-character string in under 200 microseconds, while Perl would require over 10^15 years.

Combining implementation details, finite automata, and a foray into decades-old theory, this article shows how most of our favorite little languages have an enormous performance bottlenecks for certain categories of string comparisons.

An additional data point: The Shootout benchmarks have a large string comparison test. It's interesting that Tcl is at the top of the heap for performance. Guess which one is using the Thompson NFA algorithm for regular expressions?