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author | Tomas Volf <~@wolfsden.cz> | 2024-05-19 00:47:07 +0200 |
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committer | Ludovic Courtès <ludo@gnu.org> | 2024-10-26 19:45:11 +0200 |
commit | 1c093d8bc4b74bd7392f1520c2135d8ba40a2735 (patch) | |
tree | aaf05d0957a423a0db4fbe3afddfbc0d5124c269 /doc/ref/libguile-program.texi | |
parent | a0368a61204e02b892069b5a7937b0c3900215ae (diff) | |
download | guile-1c093d8bc4b74bd7392f1520c2135d8ba40a2735.tar.gz |
doc: Recommend alist-copy instead of list-copy.
The current recommendation of `list-copy' is not right and does not lead
to preserving the original list:
scheme@(guile-user)> (define x (list (cons 'a 1) (cons 'b 2)))
scheme@(guile-user)> (define y (list-copy x))
scheme@(guile-user)> (assq-set! y 'b 3)
$1 = ((a . 1) (b . 3))
scheme@(guile-user)> x
$2 = ((a . 1) (b . 3))
Correct approach seems to be use `alist-copy' from SRFI-1 leading to the
expected behavior of:
scheme@(guile-user)> ,use (srfi srfi-1)
scheme@(guile-user)> (define x (list (cons 'a 1) (cons 'b 2)))
scheme@(guile-user)> (define y (alist-copy x))
scheme@(guile-user)> (assq-set! y 'b 3)
$1 = ((a . 1) (b . 3))
scheme@(guile-user)> x
$2 = ((a . 1) (b . 2))
* doc/ref/api-data.texi (Adding or Setting Alist Entries): Recommend
`alist-copy'.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
Diffstat (limited to 'doc/ref/libguile-program.texi')
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