Changes between Version 3 and Version 4 of ExistingRecords


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Timestamp:
Nov 29, 2005 11:24:22 AM (10 years ago)
Author:
simonpj@…
Comment:

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  • ExistingRecords

    v3 v4  
    3535would match only the Bar constructor since it is the only one with a  y field. 
    3636 
    37 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 
     37This 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. 
     38 
     39Note from Simon.  I hate that the above defn of 'f' has just one argument (val {x="foo")),  
     40whereas it looks as if it has two.  (This is a problem with existing Haskell.)  It looks 
     41like 'f' has an argument 'val' and another arguement that is a free-standing record,  
     42something we really want in the end anyhow.  Not sure how to fix this.  val@{x="foo")? 
    3843 
    3944  * first class update and setting syntax (more advanced, needs better syntax)