[bitc-dev] Call by need?

[Raoul Duke]

On Fri, Sep 3, 2010 at 9:39 PM, wren ng thornton <wren at freegeek.org> wrote:
> Indeed. This is often advocated as one of the reasons for
> lazy-by-default in Haskell. Laziness allows you to implement most
> control structures directly in the language, rather than having them as
> built-ins: short-circuiting boolean ops, if-then-else, do-while,...

i'm probably confused. couldn't you also do that if you instead had a
way to mark something as lazy? short-circuiting boolean ops in
scheme/lisp don't have to be "built-ins", can be macros, no? they are
in the Clojure sources, anyway. (just thinking of arguments i've heard
for /not/ having laziness be the default - mainly that it can be a
stretch for mere humans to follow the performance implications.) so
your 2nd sentence doesn't seem to bolster the 1st iiuc.

sincerely.