diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 66 |
1 files changed, 37 insertions, 29 deletions
@@ -7869,6 +7869,37 @@ cached inside <promise> and returned, becoming the return value of the force function call. If the force function is invoked additional times on the same promise, the cached value is retrieved. +.SS Function perm + +.TP +Syntax: + + (perm <seq> [<len>]) + +.TP +Description: + +The rperm function returns a lazy list which consists of all +length <len> permutations of formed by items taken from <seq>. +The permutations do not use any element of <seq> more than once. + +Argument <len>, if present, must be a positive integer, and <seq> must be a +sequence. + +If <len> is not present, then its value defaults to the length of <seq>: +the list of the full permutations of the entire sequence is returned. + +The permutations in the returned list are sequences of the same kind as <seq>. + +If <len> is zero, then a list containing one permutation is returned, and that +permutations is of zero length. + +If <len> exceeds the length of <seq>, then an empty list is returned, +since it is impossible to make a single non-repeating permutation that +requires more items than are available. + +The permutations are lexicographically ordered. + .SS Function rperm .TP @@ -7909,34 +7940,8 @@ Examples: (rperm '(0 1 2) 2) -> ((0 0) (0 1) (0 2) (1 0) (1 1) (1 2) (2 0) (2 1) (2 2)) -.SS Function perm - -.TP -Syntax: - - (perm <seq> [<len>]) - -.TP -Description: - -The rperm function returns a lazy list which consists of all -length <len> permutations of formed by items taken from <seq>. -The permutations do not use any element of <seq> more than once. -Argument <len>, if present, must be a positive integer no greater -than the length of <seq>, and <seq> must be a sequence. - -If <len> is not present, then its value defaults to the length of <seq>: -the list of the full permutations of the entire sequence is returned. - -The permutations in the returned list are sequences of the same kind as <seq>. - -If <len> is zero, then a list containing one permutation is returned, and that -permutations is of zero length. - -The permutations are lexicographically ordered. - -.SS Functions comb and rcomb +.SS Function comb .TP Syntax: @@ -7952,14 +7957,17 @@ length <len> non-repeating combinations formed by taking items taken from element of <seq> more than once. If <seq> contains no duplicates, then the combinations contain no duplicates. -Argument <len> must be a nonnegative integer no greater than the length of -<seq>, and <seq> must be a sequence. +Argument <len> must be a nonnegative integer, and <seq> must be a sequence. The combinations in the returned list are sequences of the same kind as <seq>. If <len> is zero, then a list containing one combination is returned, and that permutations is of zero length. +If <len> exceeds the length of <seq>, then an empty list is returned, +since it is impossible to make a single non-repeating combination that +requires more items than are available. + The combinations are lexicographically ordered. .SS Function rcomb |