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| author | Kaz Kylheku <kaz@kylheku.com> | 2019-06-17 06:54:47 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2019-06-17 14:25:35 -0700 |
| commit | 5ef6b01420fe68f40c266cec62c5b4a7931420f1 (patch) | |
| tree | 9dbb4703e9ad96e11d268538f7956128654ff194 | |
| parent | a9739d76c8275f6c867b86d8e218571e3a584ad9 (diff) | |
| download | txr-5ef6b01420fe68f40c266cec62c5b4a7931420f1.tar.gz txr-5ef6b01420fe68f40c266cec62c5b4a7931420f1.tar.bz2 txr-5ef6b01420fe68f40c266cec62c5b4a7931420f1.zip | |
carray-sub: improved accessor.
* share/txr/stdlib/ffi.tl (carray-sub): We use defset to
define a carray-sub place that updates via carray-replace,
rather than using a place macro to defer to the
generic sub accessor. This results in a more efficient
implementation. This new accessor doesn't require the carray
argument to be a place; unlike sub, it doesn't have to capture
the return value of carray-replace and store it back into
the carray variable.
* txr.1: Updated doc.
| -rw-r--r-- | share/txr/stdlib/ffi.tl | 4 | ||||
| -rw-r--r-- | txr.1 | 15 |
2 files changed, 14 insertions, 5 deletions
diff --git a/share/txr/stdlib/ffi.tl b/share/txr/stdlib/ffi.tl index ed8ad06d..6bbd43a9 100644 --- a/share/txr/stdlib/ffi.tl +++ b/share/txr/stdlib/ffi.tl @@ -145,8 +145,8 @@ (define-accessor carray-ref carray-refset) -(define-place-macro carray-sub (carray : (from 0) (to t)) - ^(sub ,carray ,from ,to)) +(defset carray-sub (carray : (from 0) (to t)) items + ^(progn (carray-replace ,carray ,items ,from ,to) ,items)) (defmacro znew (type . pairs) (if (oddp (length pairs)) @@ -65108,9 +65108,18 @@ and modifications in the original are not reflected in the subrange. If .code carray-sub -is used as a syntactic place, behaves exactly like the -.code sub -accessor, via a place macro substitution to that form. +is used as a syntactic place, the argument expressions +.metn carray , +.metn from , +.meta to +and +.meta new-val +are evaluated just once. The prior value, if required, is accessed by calling +.code carray-sub +and +.meta new-val +is then stored via +.codn carray-replace . .coNP Function @ carray-replace .synb |