[r6rs-discuss] [Formal] SRFI-39 should be made an R6RS library

[Michael Sperber]

"R. Kent Dybvig" <dyb at cs.indiana.edu> writes:

>> This suggests to me that parameters, as intended by you, are an even
>> more general mechanism than dynamic binding and thread-local
>> assignment.  As Scheme generally tries to avoid piling feature upon
>> feature, it's a better strategy to offer the building blocks and let
>> people build the parameter mechanism they want from them.
>
> Nice try!  Simple but general mechanisms like parameters, however, are
> precisely the kind of building blocks that allow us to avoid piling
> feature upon feature.  Restricting them reduces their generality and hence
> their ability to serve as a basis for other features.

Nice try!  However, parameters are neither simple nor general.
Moreover, the particular design you chose is problematic because it
destroys modularity.  In contrast, dynamic binding as a separate
mechanism is simple and modular.  Combined with thread-local storage
(less simple and not modular, but still simpler than parameters), you
can build parameters.

-- 
Cheers =8-} Mike
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