On 16 February 2005 14:28, John Goerzen wrote:

On Wed, Feb 16, 2005 at 07:16:50AM +0100, Tomasz Zielonka wrote:

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On Wed, Feb 16, 2005 at 04:33:29AM +0000, John Goerzen wrote:

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On a related note, Wash seems to be preserving all sorts of unnecessary "state" from previous screens a user visited.

You do know that the current version of WASH rebuilds the continuation by repeating all the previous steps, don't you? Until WASH can keep the

Yes. What I don't understand is why. If I have a submit button, and it is passing one value to the next function, and that value is from an entry form on the screen, why would I care about all the previous state? That's my confusion. It seems unnecessary.

WASH would have to store the value of the next function in the log, as a continuation. If that is a top-level function then it's easy, but WASH lets you use an arbitrary expression as the continuation, which might include an arbitrary amount of data captured in the free variables. Storing this continuation directly in the web page would require low-level trawling of the Haskell heap. WASH's Haskell-only solution is so neat because it doesn't need to do this: it just recreates the continuation by recording how it was created. Cheers, Simon