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Make slice a c function.

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This will allow future integration into the compiler
for more general destructuring.
This commit is contained in:
Calvin Rose 2019-11-05 09:29:32 -06:00
parent 6ceaf9d28d
commit cf2d3861d6
2 changed files with 18 additions and 5 deletions
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5
src/boot/boot.janet
View File

@ -1169,11 +1169,6 @@
(if (not= i len) (array/push ret (slicer ind i)))
ret)
(defn slice
"Extract a sub-range of an indexed data strutrue or byte sequence."
[ind &opt start end]
((if (bytes? ind) string/slice tuple/slice) ind start end))
###
###
### IO Helpers

18
src/core/corelib.c
View File

@ -342,6 +342,19 @@ static Janet janet_core_array(int32_t argc, Janet *argv) {
return janet_wrap_array(array);
}
static Janet janet_core_slice(int32_t argc, Janet *argv) {
JanetRange range = janet_getslice(argc, argv);
JanetByteView bview;
JanetView iview;
if (janet_bytes_view(argv[0], &bview.bytes, &bview.len)) {
return janet_stringv(bview.bytes + range.start, range.end - range.start);
} else if (janet_indexed_view(argv[0], &iview.items, &iview.len)) {
return janet_wrap_tuple(janet_tuple_n(iview.items + range.start, range.end - range.start));
} else {
janet_panic_type(argv[0], 0, JANET_TFLAG_BYTES | JANET_TFLAG_INDEXED);
}
}
static Janet janet_core_table(int32_t argc, Janet *argv) {
int32_t i;
if (argc & 1)
@ -665,6 +678,11 @@ static const JanetReg corelib_cfuns[] = {
JDOC("(nat? x)\n\n"
"Check if x can be exactly represented as a non-negative 32 bit signed two's complement integer.")
},
{
"slice", janet_core_slice,
JDOC("(slice x &opt start end)\n\n"
"Extract a sub-range of an indexed data strutrue or byte sequence.")
},
{NULL, NULL, NULL}
};