Ok, thanks a lot!
>>>>> "RT" == RT Happe <email@example.com> writes:
RT> On Tue, 1 Apr 2003, Francisco Vides Fernandez wrote:
>> Error: exception (set-cdr! '("b" . 2) 3)
>> But the following works fine
>> I'm using scsh 0.6.2. I have tested this with other interpreters
>> and both work fine. Is this a known bug? Am I doing something
RT> In the first case, you are trying to mutate a constant object.
RT> The Scheme report says
RT> In many systems it is desirable for constants (i.e. the values
RT> of literal expressions) to reside in read-only-memory. To express
RT> this, it is convenient to imagine that every object that denotes
RT> locations is associated with a flag telling whether that object
RT> is mutable or immutable. In such systems literal constants and
RT> the strings returned by
symbol-> string are immutable objects, while all objects created by
RT> other procedures listed in this report are mutable. It is an
RT> error to attempt to store a new value into a location that is
RT> denoted by an immutable object. (R5RS section 3.4 Storage Model)
RT> See also the section on literal expressions.
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