Re: [Haskell-cafe] Documenting strictness properties for Data.Map.Strict

On 18/11/11 06:44, Johan Tibell wrote:

On Thu, Nov 17, 2011 at 9:21 PM, Johan Tibell wrote:

...

I'm not entirely happy with this formulation. I'm looking for something that's clear (i.e. precise and concise, without leaving out important information), assuming that the reader already knows how lazy evaluation works at a high level.

Ideas?

This reads a bit better to me:

I actually much prefer the original formulation. In particular, you should keep examples together with the rules they illustrate.

* key and value function arguments passed to functions are evaluated to WHNF before the function body is evaluated, and

"function arguments passed to functions" sounds a bit redundant. Either say "arguments passed to functions" or "function arguments". Also "before the function body is evaluated" says something about evaluation order, does that really matter for strictness? * All key and value arguments passed to functions are evaluated to WHNF before the function body is evaluated

* keys and values returned by high-order function arguments are evaluated to WHNF before they are inserted into the map.

Keys and values not returned by higher order functions, but passed in directly are also evaluated to WHNF (per the first rule), so that qualification is unnecessary. Just say: * keys and values are evaluated to WHNF before they are inserted into the map. I also think 'stored' is better here than 'inserted', because the latter might give the impression that it only applies to the insert function, and not to things like map.

insertWith (+) k undefined m == undefined etc.

As Roman suggested, use = here instead of ==. To really illustrate the first rule, insertWith (+) is not enough, you would really need a function that doesn't use the value, so insertWith (\new old -> old) k undefined m = undefined But that is just nitpicking. Twan