On Sep 10, 2011, at 7:03 AM, Ábel Sinkovics <abel@elte.hu> wrote:
Hi Gordon,
"Nested Lambda Expressions with Let Expressions in C++ Template Metaprograms" explains metamonad's lambda expressions. The major difference between that approach and MPL's lambda expressions is that metamonad lambda expressions let the user specify the name of the arguments instead of calling them _1, _2, etc.
Wonderful! This would clarify my algos greatly. Seems like it shouldn't be much slower either.
I'm not aware of techniques based on monads that help implementing data-structues. They are good at abstracting behaviours (error handling, non-determinism, etc.), they should help you with error propagation in your algorithms (see compile-time exceptions in metamonad).
Hmm, I've got plenty to learn about FP. Monad seems to mean a lot of things. Maybe I was only thinking of the kind that wraps real side effects like memory writes. Anyway this still seems very helpful. In particular I have been writing the tests without failure cases because a compilation error is not a great expected failure. I look forward to exploring further.
lazy_eval_if: 3.89 s eval_if: 3.65 s
As you can see, there is some overhead (lazy_eval_if uses eval_if), however it may be different with other compilers.
Not too bad. I'd like to know what the penalty for a larger algorithm is - also for the lambdas and exceptions/monad stuff. When I get a chance I may try porting my depth_first_search to your libs to find out. Thanks, Gordon