Re: Proposal: require spaces around the dot operator

There are 2 compelling reasons I know of to prefer dot for record access 1) follows an almost universal convention in modern programming languages 2) is consistent with using the dot to select functions from module name-spaces We can have a lot of fun bike-shedding about what operator we would prefer were these constraints not present. Personally I wouldn't care. However, I find either one of these 2 points reason enough to use the dot for record field access, and even without a better record system the second point is reason enough to not use dot for function composition. It is somewhat convenient to argue that it is too much work and discussion for something one is discussing against. The only point that should matter is how existing Haskell code is effected. On Thu, Feb 9, 2012 at 8:27 PM, Daniel Peebles wrote:

I'm very happy to see all the work you're putting into the record discussion, but I'm struggling to see why people are fighting so hard to get the dot character in particular for field access. It seems like a huge amount of work and discussion for a tiny bit of syntactic convenience that we've only come to expect because of exposure to other very different languages.

Is there some fundamental reason we couldn't settle for something like # (a valid operator, but we've already shown we're willing to throw that away in the MagicHash extension) or @ (only allowed in patterns for now)? Or we could even keep (#) as a valid operator and just have it mean category/lens composition.

Thanks, Dan

On Thu, Feb 9, 2012 at 9:11 PM, Greg Weber wrote:

...

Similar to proposal #20, which wants to remove it, but immediately less drastic, even though the long-term goal is the same. This helps clear the way for the usage of the unspaced dot as a record field selector as shown in proposal #129.

After this proposal shows clear signs of moving forward I will add a proposal to support a unicode dot for function composition. After that we can all have a lively discussion about how to fully replace the ascii dot with an ascii alternative such as <~ or <<< After that we can make the dot operator illegal by default.

This has already been discussed as part of a records solution on the ghc-users mail list and documented here: http://hackage.haskell.org/trac/ghc/wiki/Records/DotOperator

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