[ sisc-Bugs-1320677 ] append functions do not produce mutable copies

Bugs item #1320677, was opened at 2005-10-09 18:27
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 7
Submitted By: Matthias Radestock (mradestock)
Assigned to: Nobody/Anonymous (nobody)
Summary: append functions do not produce mutable copies

Initial Comment:
According to R5RS, |append| and |string-append| is
supposed to produce copies, which, since they are
copies, ought to be mutable even when the original wasn't.

SISC gets this wrong for the last list in an |append|
and single-arg |string-append|;

#;> (define l1 '())
#;> (define l2 (append l1))
#;> (define l3 (append '() l1))
#;> (eq? l1 l2)
#t
#;> (set-car! l2 2)
Error in set-car!: expected type pair, got '()'.
console:165:1: <from call to set-car!>
#;> (set-car! l3 2)
Error in set-car!: expected type pair, got '()'.
console:166:1: <from call to set-car!>
#;> (define s1 "foo")
#;> (define s2 (string-append s1))
#;> (eq? s1 s2)
#t
#;> (string-set! s2 0 #\b)
Error in string-set!: string is immutable.
console:170:1: <from call to string-set!>


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