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Re: [Scheme-reports] REPL

On Wed, Nov 14, 2012 at 4:49 PM, Helmut Eller <eller.helmut@x> wrote:
Section 5.7 talks about a mysterious "top-level" environment.  Is
this any different from the (interaction-environment)?

The definition of interaction-environment states:

  The intent is that this procedure will return the environment in which
  the implementation would evaluate expressions entered by the user into
  a REPL.

Thus it is suggested, but not required, for these to
be the same.  Due to implementation differences
It's difficult to specify much about the REPL.

Regardless, interaction-environment is mutable and
thus suitable for implementing your own, portable REPL.

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

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.


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