Re: [Haskell-beginners] FW: question

On Thu, Jul 14, 2011 at 6:16 AM, Benjamin Edwards wrote:

Hi Roelof,

I don't want to come across as rude here, and I am sure the rest of the list will shoot me down if I do, but you had a number of people trying to diagnose a problem caused mostly by a failure on your part to type out correctly what you have read. You are going to find it very hard to make meaningful progress in your quest to learn Haskell if you don't take the time to at least learn the basic syntax of the language before coming to the mailing lists for help.

I agree, but here's something I'd like to point out: IIRC, Roelof uses "Programming in Haskell" as his learning material. One thing that I found confusing in that book (and in other books as well), is that the authors insist on using LaTeX mathematical symbols in Haskell code instead of "valid Haskell syntax". For example, in the exact example from the book that Roelof is trying to understand: [x^2 | x <- [1..5]] , the caret ('^') is not a caret, it's "an arrow pointing upwards", and the ASCII arrow ("<-") is not an ASCII arrow composed of '<' and '-', but instead "a single-character arrow". A table at the end of the book (Appendix B) explains the correspondance, but that might not be immediately obvious. What are the benefits of having Haskell code samples (in a book specifically about learning Haskell) not being valid Haskell syntax? Why burden the beginner with the task of mentally translating these symbols? Patrick

Best, Ben

On 14 Jul 2011 10:48, "Roelof Wobben" wrote:

Hello

That was the problem.

When I do <- instead of <-- I see outcome.

So this problem is also solved.

Everyone thanks for the help and patience.

Roelof

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Date: Thu, 14 Jul 2011 09:25:33 +0100 Subject: Re: [Haskell-beginners] FW: question From: edwards.benj@gmail.com To: luca_ciciriello@hotmail.com CC: beginners@haskell.org; rwobben@hotmail.com

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The first problem I see is that "x <--" is wrong... it should be just x <-, a single hyph...

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mailto:luca_ciciriello@hotmail.com>

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wrote:

Hi. On wich system are you using GHCi ? Probably I missed this information from...

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