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| author | Kaz Kylheku <kaz@kylheku.com> | 2018-01-01 15:55:58 -0800 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2018-01-01 15:55:58 -0800 |
| commit | 79a90b980192de7410a7e688e1c831f7878f8714 (patch) | |
| tree | 8aaf9ce2e0a0fb6d79c36d3cc2c117039f2a6390 /txr.1 | |
| parent | 900597a05d48be775bfb0e504e3179062806ff02 (diff) | |
| download | txr-79a90b980192de7410a7e688e1c831f7878f8714.tar.gz txr-79a90b980192de7410a7e688e1c831f7878f8714.tar.bz2 txr-79a90b980192de7410a7e688e1c831f7878f8714.zip | |
sub and replace redirect to structure methods.
* lib.c (replace_obj): New static function.
(sub): Handle struct case via lambda method.
(replace): Handle struct case via replace_obj.
* txr.1: Documented.
* tests/012/aseq.tl (add): The lambda method now has to handle
a range argument. One test case uses the last function, which
for non-lists relies on sub, which now calls the lambda method
if the object has one.
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 81 |
1 files changed, 81 insertions, 0 deletions
@@ -25961,6 +25961,32 @@ is a object, then the function behaves like .codn carray-sub . +If +.meta sequence +is a structure, it must support the +.code lambda +method. The +.code sub +operation is transformed into a call to the +.code lambda +method according to the following equivalence: + +.cblk + (sub o from to) <--> o.(lambda (rcons from to)) + (sub o : to) <--> o.(lambda (rcons : to)) + (sub o from) <--> o.(lambda (rcons from :)) + (sub o) <--> o.(lambda (rcons : :)) +.cble + +That is to say, the +.meta from +and +.code to +arguments are converted to range object. If either argument +is missing, the symbol +.code : +is used for the corresponding element of the range. + When a .code sub form is used as a syntactic place, that place denotes a slice of @@ -26107,6 +26133,61 @@ object, then behaves like .codn carray-replace . +If +.meta sequence +is a structure, then the structure must support the +.code lambda-set +method. The +.code replace +operation is translated into a call of the +.code lambda-set +method according to the following equivalences: + +.cblk + (replace o items from to) + <--> o.(lambda-set (rcons from to) items) + + (replace o items index-list) + <--> o.(lambda-set index-list items) +.cble + +Thus, the +.meta from +and +.meta to +arguments are converted to single range object, +whereas an +.meta index-list +is passed as-is. +It is an error if a +.code to +argument is given, and +.code from +is a list; the situation is diagnosed. If either +.code from +or +.code to +are omitted, the range object contains the +.code : +symbol in the corresponding place: + +.cblk + (replace o items from) + <--> o.(lambda-set (rcons from :) items) + + (replace o items : to) + <--> o.(lambda-set (rcons : to) items) + + (replace o items) + <--> o.(lambda-set (rcons : :) items) +.cble + +It is the responsibility of the object's +.code lambda-set +method to implement semantics consistent with the +description of +.codn replace . + .coNP Function @ take .synb .mets (take < count << sequence ) |