how implement takeWhile

[bioinfornatics]

Dear,
1/

i would like have a code near as this haskell code:

fibs = 1 : 1 : zipWith (+) fibs (tail fibs)

main = do
	print $ sum (filter even (takeWhile (<4000000) fibs))




Ii know in D:
- auto fib = recurrence!("a[n-1] + a[n-2]")(1, 1);
- std.algorithm.until
- std.algorithm.filler
- std.algorithm.reduce
- std.range.InputRange.popFront
- std.range.take
- std.array.appender

       but i do not see how to these feature together to have a 
code
close to the haskell code.

Someone?

2/
Someone  know to generate a fibonacci list directly with a lambda
syyntax and not from string ("a[n-1] + a[n-2]") ?

thanks