Re: Why is package user not an environment in MIT Scheme 10.1?

[Chris Hanson]

The change is mainly because package objects are being phased out, and 
will eventually be replaced by R7RS libraries.

You can of course use (->environment '(user)) instead.

On 2019-11-16 21:53, Lone Learner wrote:
> Here is my MIT Scheme code:
>
> (display (name->package '(user)))
> (newline)
> (->environment (name->package '(user)))
> (%exit)
>
> This runs fine on MIT/GNU Scheme Release 9.1.1. Here is the output:
>
> $ scheme --quiet --load foo.scm
> #[package 13 (user)]
>
> But when I run this with MIT/GNU Scheme Release 10.1.5, I get this 
> error:
>
> $ mit-scheme --quiet --load foo.scm
> #[package 12 (user)]
> ;The object #[package 12 (user)], passed as an argument to
> ->environment, is not an environment.
> ;To continue, call RESTART with an option number:
> ; (RESTART 1) => Return to read-eval-print level 1.
>
> 2 error>
>
> On debugging I get this,
>
> 2 error> (debug)
>
> There are 7 subproblems on the stack.
>
> Subproblem level: 0 (this is the lowest subproblem level)
> Compiled code expression unknown
> #[compiled-return-address 13 ("rep" #x2f) #xd8 #x95ed10]
> There is no current environment.
> There is no execution history for this subproblem.
> You are now in the debugger.  Type q to quit, ? for commands.
>
> 3 debug>
>
> Why does this error occur in 10.1.5 but not in 9.1.1?