Re: [Scheme-reports] REPL

[Alex Shinn <alexshinn@x>]

On Wed, Nov 14, 2012 at 6:09 PM, Helmut Eller <eller.helmut@x> wrote:

On Wed, Nov 14 2012, Alex Shinn wrote:

> On Wed, Nov 14, 2012 at 5:46 PM, Helmut Eller <eller.helmut@x> wrote:
>
>     On Wed, Nov 14 2012, Alex Shinn wrote:
>
>     >     In Section 5.2 says that a REPL should permit to redefine existing
>     >     definitions.  What should happen if a record definition is
>     redefined?
>     >     Should existing record instances be considered instances of the new
>     >     type?
>     >
>     > Again, implementations differ here so there's not much
>     > we can say.  Smalltalk-style class redefinition is a nice
>     > feature, but fragile and not currently widely implemented.
>
>     You can say what "should" happen.
>
> We could say that iff everyone agreed on what should happen.

Then why can you say that a REPL "should" support redefinition?
(Without defining what redefinition means.)

This refers to redefining variables and syntax in general.

For the specific case of redefining record types we could

add a note that existing instances may or may not be

mapped to the new type according to some unspecified

semantics, but I'm not sure if such a note adds anything.

-- 

Alex

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