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Changes between Version 13 and Version 14 of ExistingRecords

v13	v14
36	36	This would mitigate the problems caused by accessors being partial functions since you can use a simple case statement to get the effect of an accesor that returns its result in a Maybe.
37	37
38		~~Note from Simon~~. I hate that the above defn of 'f' has just one argument (val {x="foo")),
	38	'''Note from Simon'''. I hate that the above defn of 'f' has just one argument (val {x="foo")),
39	39	whereas it looks as if it has two. (This is a problem with existing Haskell.) It looks
40	40	like 'f' has an argument 'val' and another arguement that is a free-standing record,
…	…
69	69	Note the change in the type of the stored field.
70	70	At the moment, such a record update must be written using the data constructor, not the update syntax.
	71
	72	'''SLPJ:''' That isn't true. Haskell 98 already supports what you suggest here, and the code above compiles with GHC without flags.
	73
	74	However I would like to argue for ''removing'' this feature. It causes a quite unreasonable amount of
	75	pain in the type checker, especially once we start thinking about GADTs and existentials. And I think the benefit is modest at best. I don't think programmers generally expect record update to be a type-changing operation.
	76
	77
71	78	== 'Open' statement ==
72	79