Lexical closures

You already mentioned these :-) Closures are so incredibly useful I don't really want to code without them, but if I must, the language should at least support functions as a data type (i.e. C-style function pointers). Java-style object systems are a much too rigid on their own.

Closures and its flexible object system are what make JavaScript a good language. Shame about the ugly syntax, though :-)

Basically, anything that helps writing real functional code is a big plus.

Backtracking.

It's sort of a niche technique, but it's amazingly useful when applicable. See also the discussion at How implement AMB in perl?

A "freestyle" type/object system

I like perl's automatic type conversions. I like Ruby's strategy of duck-typing. I like C-style pointer casting. I even like the idea behind C++ templates. I don't like being restricted by the language.

"Real (i.e. LISP-style) Macros"

Anything that allows you to subvert the language itself is a good thing :-) Though it seems it's hard to implement unless the language syntax is extremely simple (this might not be a bad thing, I'm only just getting my feet wet with LISP, so it just looks more intimidating than it probably is :-) )

"What should it profit a man, if he should win a flame war, yet lose his cool?"

In reply to Re: What do you use as a language litmus? by Joost
in thread What do you use as a language litmus? by apotheon

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