| > For example: | > | > f = | > let g = (THUNK h x) | > in (CONS g y) | > | > Is this exactly the same as (right variant following the paper) | > | > f = | > let g = (THUNK h x) | > in let freshvar = (CONS g y) | > in freshvar Yes that's right. The only problem with the latter is that it's not syntactically apparent that 'freshvar' is a value, and hence can be returned immediately rather than entered. But one can solve that by maintaining an environment telling static info about in-scope variables, which the code gen needs to do anyway. | > And the second question is how does constructor tag is passed to case | > when non-vector return is used? In register? In constructor closure? | > Are there any cases when closure is not build for constructor | > application? What the case binder is bound to if there is no closure | > for constructor application? Read our paper "Faster laziness using dynamic pointer tagging"! It's new (ICFP'07) http://research.microsoft.com/~simonpj/papers/ptr-tag/index.htm simon