[Haskell-cafe] Re: Is lazyness make big difference?

[apfelmus at quantentunnel.de]

Nick wrote:
> The question is the following: how big the gap between strict languages
> with lazy constructs and Haskell? Does the default lazyness have
> irrefutable advantage over default strictness?

Laziness is needed to achieve true compositionality. This point is
elaborated in

  John Hughes. "Why functional programming matters"
  http://haskell.org/haskellwiki/Research_papers#Overview

I also think that the laziness in Haskell is already so implicit that
90% of the Haskell code written so far will simply break irreparably if
you experimentally remove it.


By the way, lazy evaluation is strictly more powerful than eager
evaluation (in a pure language, that is) with respect to asymptotic
complexity:

  Richard Bird, Geraint Jones and Oege de Moor.
  "More Haste, Less Speed."
  http://web.comlab.ox.ac.uk/oucl/work/geraint.jones/morehaste.html


Regards,
apfelmus