[Haskell] NYTimes.com: John W. Backus, 82, Fortran Developer, Dies

Douglas Philips dgou at mac.com
Tue Mar 20 15:37:28 EDT 2007

On 2007 Mar 20, at 3:30 PM, Dan Weston indited:

> I looked up John Backus on wikipedia and followed a link to ALGOL:
> http://en.wikipedia.org/wiki/ALGOL_60
> where the following "undesirable" property of call-by-name is  
> mentioned.
> "ALGOL 60 allowed for two evaluation strategies for parameter  
> passing: the common call-by-value, and call-by-name. Call-by-name  
> had certain limitations in contrast to call-by-reference, making it  
> an undesirable feature in language design. For example, it is  
> impossible in ALGOL 60 to develop a procedure that will swap the  
> values of two parameters if the actual parameters that are passed  
> in are an integer variable and an array that is indexed by that  
> same integer variable. However, call-by-name is still beloved of  
> ALGOL implementors for the interesting thunks that are used to  
> implement it."
> I suppose that call-by-name is still beloved of Haskell  
> implementors as well?

Notice that the "problem" with call-by-name is when side-effects are  
involved. In a pure-functional-environment those "problems" don't  


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