Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-14 Thread Stuart Cook
From Fixing Haskell IO: We can summarize the SDIOH (Standard Definition of IO in Haskell) as a value of type IO a is a value, that performs, then delivers a value of type a. I think you've already made a critical mistake here. The quotes you give all describe an IO value as something that when

Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-14 Thread Gregg Reynolds
On Sat, Feb 14, 2009 at 9:15 AM, Stuart Cook sco...@gmail.com wrote: From Fixing Haskell IO: We can summarize the SDIOH (Standard Definition of IO in Haskell) as a value of type IO a is a value, that performs, then delivers a value of type a. I think you've already made a critical

[Haskell-cafe] IO semantics and evaluation - summary

2009-02-13 Thread Gregg Reynolds
Many thanks to everybody who tried to set me straight on the thread about IO monad and evaluation semantics. I've begun summarizing the info, and I believe I've come up with a much better way of explaining IO; just flip the semantic perspective, and think in terms of interpretations instead of

Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-13 Thread Daryoush Mehrtash
I have been trying to figure out the distinction between value, function and computation. You raised a few points that I am not sure about. In Computation considered harmful. Value not so hot either. you said: I still don't like it; a lambda expression is not a computation, it's a formal

Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-13 Thread Roman Cheplyaka
* Daryoush Mehrtash dmehrt...@gmail.com [2009-02-13 11:31:06-0800] Isn't the lambda expression a representation of something (potentially with recursion) that yields a value and not the value itself? The same terms may refer to different notions. If you think of values as mathematical

Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-13 Thread Gregg Reynolds
Hi Daryoush, 2009/2/13 Daryoush Mehrtash dmehrt...@gmail.com I have been trying to figure out the distinction between value, function and computation. You raised a few points that I am not sure about. In Computation considered harmful. Value not so hot either. you said: I still

Re: [Haskell-cafe] IO semantics and evaluation - summary

2009-02-13 Thread roconnor
I also recommend reading http://www.haskell.org/haskellwiki/IO_Semantics (mostly because I wrote it). Feel free to improve upon it. -- Russell O'Connor http://r6.ca/ ``All talk about `theft,''' the general counsel of the American Graphophone Company wrote,