27 Mar
2009
27 Mar
'09
5:32 p.m.
On Fri, 2009-03-27 at 14:26 -0700, Kirk Martinez wrote:
Your powersOfTwo function, since it gets memoized automatically (is this the case for all functions of zero arguments?),
It is the case for all functions which have zero arguments *at the time they are presented to the code generator*. The infamous evil monomorphism restriction arises from the fact that overloaded expressions, such as negative_one = exp(pi * sqrt(-1)) look like functions of zero arguments, but are not, and hence do not get memoized. This behavior was considered sufficiently surprising, when it was discovered in early Haskell compilers, that the construct was outlawed from the language entirely. jcc