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author | Kaz Kylheku <kaz@kylheku.com> | 2021-09-02 06:59:47 -0700 |
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committer | Kaz Kylheku <kaz@kylheku.com> | 2021-09-02 06:59:47 -0700 |
commit | 6cf10bb9919aa27735f7d13539aaa871400777e4 (patch) | |
tree | d0ad10c70e01a5ea668105ff1ca882b111811f60 /lib.c | |
parent | bc987afb87416418841573cd858258438be9f2ea (diff) | |
download | txr-6cf10bb9919aa27735f7d13539aaa871400777e4.tar.gz txr-6cf10bb9919aa27735f7d13539aaa871400777e4.tar.bz2 txr-6cf10bb9919aa27735f7d13539aaa871400777e4.zip |
New function: delcons.
* eval.c (eval_init): Register delcons intrinsic.
* lib.[ch] (delcons): New function.
* tests/010/cons.tl: New file.
* txr.1: Documented.
* stdlib/doc-syms.tl: Updated.
Diffstat (limited to 'lib.c')
-rw-r--r-- | lib.c | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -2796,6 +2796,28 @@ val tailp(val obj, val list) return t; } +val delcons(val cons, val list) +{ + val iter = list; + + if (!consp(cons)) + return list; + + if (cons == iter) + return cdr(iter); + + while (consp(iter)) { + val d = us_cdr(iter); + if (cons == d) { + us_rplacd(iter, us_cdr(cons)); + break; + } + iter = d; + } + + return list; +} + val memq(val obj, val list) { val list_orig = list; |