[Noisebridge-discuss] Haschool

[d p chang]

Jason Dusek <jason.dusek at gmail.com> writes:

> 2009/05/09 d p chang:
>> Jason Dusek <jason.dusek at gmail.com> writes:
>>> Haskell invites us to consider computation from the
>>> perspective of the typed lambda calculus.
>>
>> i've not thought at this level in a while, but isn't lambda
>> calculus normally thought of as being normal order (pun
>> intended :-) rather than haskell's lazy order?
>
>   Well, normal order (outermost first) is actually quite
>   compatible with Haskell's lazy evaluation. When you evaluate
>   (at define time or at use time) is distinct from the order
>   you evaluate in (leftmost or rightmost).

i was thinking about your first statement not expression evaluation
order. i recalled (probably incorrectly and from an ancient version of
the language) that the default was lazy (your 'use time' or 'call be
need') and that one had to 'wrap' (in a monad) to get 'outermost first'.

>   To consider laziness in context with referential transparency,
>   evaluation strategies and sharing would make for a long email.
>   This is certainly a direction we could take in the course.

that would be interesting, says my inner language theory nerd :-)

\p
---
The moral universe is a long arc, but it bends towards justice.
		--- Martin Luther King, Jr.