diff options
| -rw-r--r-- | lib.c | 3 | ||||
| -rw-r--r-- | tests/012/aseq.tl | 11 | ||||
| -rw-r--r-- | txr.1 | 53 |
3 files changed, 63 insertions, 4 deletions
@@ -13453,9 +13453,6 @@ val dwim_del(val place_p, val seq, val ind_range) (void) remhash(seq, ind_range); return seq; } - if (obj_struct_p(seq)) - uw_throwf(error_s, lit("index/range delete: not supported for structs"), - nao); default: break; } diff --git a/tests/012/aseq.tl b/tests/012/aseq.tl index dfb20118..e1a55fb8 100644 --- a/tests/012/aseq.tl +++ b/tests/012/aseq.tl @@ -8,7 +8,11 @@ (:method lambda (me i) (if (rangep i) (mapcar (op + me.n) [me.list i]) - (+ me.n (ref me.list i))))) + (+ me.n (ref me.list i)))) + (:method lambda-set (me i nv) + (if (rangep i) + (set [me.list i] (mapcar (lop - me.n) nv)) + (set [me.list i] (- nv me.n))))) (defvarl o (new (add 3 (range 10 100 10)))) @@ -16,3 +20,8 @@ (test (cadr o) 23) (test [o 4] 53) (test (cadr (last o)) nil) + +(test (set [o 0..3] '(1003 1103 1203)) (1003 1103 1203)) +(test o.list (1000 1100 1200 40 50 60 70 80 90 100)) +(test (del [o 1..4]) (1103 1203 43)) +(test o.list (1000 50 60 70 80 90 100)) @@ -43611,6 +43611,59 @@ place denotes a value stored in a dynamic data set such as a hash table, then deletion of that place implies deletion of the entry which holds that value. If the entry is identified by a key, that key is also removed. +If +.code place +is a DWIM bracket expression indexing into a structure, the structure +is expected to implement the +.code lambda +and +.code lambda-set +methods. Moreover, the place form must have only two arguments: +the object and an index argument. In other words, the +.code del +form must have this syntax: + +.mono +.mets (del >> [ obj << index ]) +.onom + +The +.code lambda +method will be invoked with the unmodified +.meta obj +and +.meta index +arguments to determine the prior value to be returned. +Then the +.code lambda-set +method will be invoked with three arguments: +.metn obj , +a possibly modified +.meta index +value and the argument +.code nil +representing an empty replacement sequence. + +If +.meta index +is a sequence or range, it is passed to the +.code lambda-set +method unmodified. Otherwise it is expected to be an integer, and +converted into a one-element range spanning the indicated element. +For instance, if the +.meta index +value is +.codn 3 , +it is converted to the range +.codn "#R(3 4)" . +In effect, the +.code lambda-set +method is thereby asked to replace the one-element subsequence starting at +index +.code 3 +with the empty sequence +.codn nil . + .coNP Macro @ lset .synb .mets (lset <> { place }+ << sequence-expr ) |