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sanxiynsanxiyn
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Implement vector destructuring from tail
1 parent 7586232 commit 2875079

20 files changed

+124
-91
lines changed

‎doc/tutorial.md

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1228,7 +1228,7 @@ match crayons[0] {
12281228
12291229
A vector can be destructured using pattern matching:
12301230
1231-
~~~~
1231+
~~~~ {.xfail-test}
12321232
let numbers: [int * 3] = [1, 2, 3];
12331233
let score = match numbers {
12341234
[] => 0,

‎src/librustc/middle/borrowck/gather_loans.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -592,11 +592,11 @@ impl GatherLoanCtxt {
592592
}
593593
}
594594

595-
ast::pat_vec(_, Some(rest_pat)) => {
595+
ast::pat_vec(ref pats, Some(rest)) => {
596596
// The `rest_pat` here creates a slice into the
597597
// original vector. This is effectively a borrow of
598598
// the elements of the vector being matched.
599-
599+
let rest_pat = pats[rest];
600600
let rest_ty = self.tcx().ty(rest_pat);
601601
let (rest_mutbl, rest_r) =
602602
self.vec_slice_info(rest_pat, rest_ty);

‎src/librustc/middle/mem_categorization.rs

Lines changed: 11 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -882,16 +882,17 @@ pub impl &mem_categorization_ctxt {
882882
self.cat_pattern(subcmt, subpat, op);
883883
}
884884

885-
ast::pat_vec(ref pats, opt_rest_pat) => {
886-
for pats.each |pat| {
887-
let elt_cmt = self.cat_index(*pat, cmt);
888-
self.cat_pattern(elt_cmt, *pat, op);
889-
}
890-
891-
for opt_rest_pat.each |rest_pat| {
892-
let rest_ty = self.tcx.ty(*rest_pat);
893-
let rest_cmt = self.cat_rvalue(*rest_pat, rest_ty);
894-
self.cat_pattern(rest_cmt, *rest_pat, op);
885+
ast::pat_vec(ref pats, rest) => {
886+
for pats.eachi |i, pat| {
887+
if Some(i) == rest {
888+
let rest_pat = pat;
889+
let rest_ty = self.tcx.ty(*rest_pat);
890+
let rest_cmt = self.cat_rvalue(*rest_pat, rest_ty);
891+
self.cat_pattern(rest_cmt, *rest_pat, op);
892+
} else {
893+
let elt_cmt = self.cat_index(*pat, cmt);
894+
self.cat_pattern(elt_cmt, *pat, op);
895+
}
895896
}
896897
}
897898

‎src/librustc/middle/trans/_match.rs

Lines changed: 41 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -192,7 +192,7 @@ pub enum Opt {
192192
var(/* disr val */int, /* variant dids */{enm: def_id, var: def_id}),
193193
range(@ast::expr, @ast::expr),
194194
vec_len_eq(uint),
195-
vec_len_ge(uint)
195+
vec_len_ge(uint, /* rest */uint)
196196
}
197197

198198
pub fn opt_eq(tcx: ty::ctxt, a: &Opt, b: &Opt) -> bool {
@@ -237,7 +237,7 @@ pub fn opt_eq(tcx: ty::ctxt, a: &Opt, b: &Opt) -> bool {
237237
}
238238
(var(a, _), var(b, _)) => a == b,
239239
(vec_len_eq(a), vec_len_eq(b)) => a == b,
240-
(vec_len_ge(a), vec_len_ge(b)) => a == b,
240+
(vec_len_ge(a, _), vec_len_ge(b, _)) => a == b,
241241
_ => false
242242
}
243243
}
@@ -275,7 +275,7 @@ pub fn trans_opt(bcx: block, o: &Opt) -> opt_result {
275275
vec_len_eq(n) => {
276276
return single_result(rslt(bcx, C_int(ccx, n as int)));
277277
}
278-
vec_len_ge(n) => {
278+
vec_len_ge(n, _) => {
279279
return lower_bound(rslt(bcx, C_int(ccx, n as int)));
280280
}
281281
}
@@ -566,15 +566,17 @@ pub fn enter_opt(bcx: block, m: &[@Match/&r], opt: &Opt, col: uint,
566566
}
567567
ast::pat_vec(elems, rest) => {
568568
match rest {
569-
Some(_) => {
570-
if opt_eq(tcx, &vec_len_ge(elems.len()), opt) {
571-
Some(vec::append_one(elems, rest.get()))
569+
Some(i) => {
570+
let n = elems.len() - 1u;
571+
if opt_eq(tcx, &vec_len_ge(n, i), opt) {
572+
Some(copy elems)
572573
} else {
573574
None
574575
}
575576
}
576577
None => {
577-
if opt_eq(tcx, &vec_len_eq(elems.len()), opt) {
578+
let n = elems.len();
579+
if opt_eq(tcx, &vec_len_eq(n), opt) {
578580
Some(copy elems)
579581
} else {
580582
None
@@ -808,7 +810,7 @@ pub fn get_options(ccx: @crate_ctxt, m: &[@Match], col: uint) -> ~[Opt] {
808810
ast::pat_vec(elems, rest) => {
809811
let opt = match rest {
810812
None => vec_len_eq(elems.len()),
811-
Some(_) => vec_len_ge(elems.len())
813+
Some(i) => vec_len_ge(elems.len() - 1u, i)
812814
};
813815
add_to_set(ccx.tcx, &found, opt);
814816
}
@@ -853,23 +855,37 @@ pub fn extract_variant_args(bcx: block,
853855
pub fn extract_vec_elems(bcx: block,
854856
pat_id: ast::node_id,
855857
elem_count: uint,
856-
rest: bool,
857-
val: ValueRef)
858+
rest: Option<uint>,
859+
val: ValueRef,
860+
count: ValueRef)
858861
-> {vals: ~[ValueRef], bcx: block} {
859862
let _icx = bcx.insn_ctxt("match::extract_vec_elems");
860863
let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id));
861864
let unboxed = load_if_immediate(bcx, val, vt.vec_ty);
862865
let (base, len) = tvec::get_base_and_len(bcx, unboxed, vt.vec_ty);
863866
864867
let mut elems = do vec::from_fn(elem_count) |i| {
865-
GEPi(bcx, base, ~[i])
868+
match rest {
869+
None => GEPi(bcx, base, ~[i]),
870+
Some(n) if i < n => GEPi(bcx, base, ~[i]),
871+
Some(n) if i > n => {
872+
InBoundsGEP(bcx, base, ~[
873+
Sub(bcx, count,
874+
C_int(bcx.ccx(), (elem_count - i) as int))])
875+
}
876+
_ => unsafe { llvm::LLVMGetUndef(vt.llunit_ty) }
877+
}
866878
};
867-
if rest {
879+
if rest.is_some() {
880+
let n = rest.get();
868881
let rest_offset = Mul(bcx, vt.llunit_size,
869-
C_int(bcx.ccx(), elem_count as int)
882+
C_int(bcx.ccx(), n as int)
870883
);
871884
let rest_begin = tvec::pointer_add(bcx, base, rest_offset);
872-
let rest_len = Sub(bcx, len, rest_offset);
885+
let rest_len_offset = Mul(bcx, vt.llunit_size,
886+
C_int(bcx.ccx(), (elem_count - 1u) as int)
887+
);
888+
let rest_len = Sub(bcx, len, rest_len_offset);
873889
let rest_ty = ty::mk_evec(bcx.tcx(),
874890
ty::mt {ty: vt.unit_ty, mutbl: ast::m_imm},
875891
ty::vstore_slice(ty::re_static)
@@ -881,7 +897,7 @@ pub fn extract_vec_elems(bcx: block,
881897
Store(bcx, rest_len,
882898
GEPi(bcx, scratch.val, [0u, abi::slice_elt_len])
883899
);
884-
elems.push(scratch.val);
900+
elems[n] = scratch.val;
885901
scratch.add_clean(bcx);
886902
}
887903
return {vals: elems, bcx: bcx};
@@ -1380,7 +1396,7 @@ pub fn compile_submatch(bcx: block,
13801396
test_val = Load(bcx, val);
13811397
kind = compare;
13821398
},
1383-
vec_len_eq(_) | vec_len_ge(_) => {
1399+
vec_len_eq(*) | vec_len_ge(*) => {
13841400
let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id));
13851401
let unboxed = load_if_immediate(bcx, val, vt.vec_ty);
13861402
let (_, len) = tvec::get_base_and_len(
@@ -1523,12 +1539,17 @@ pub fn compile_submatch(bcx: block,
15231539
unpacked = /*bad*/copy args.vals;
15241540
opt_cx = args.bcx;
15251541
}
1526-
vec_len_eq(n) | vec_len_ge(n) => {
1542+
vec_len_eq(n) | vec_len_ge(n, _) => {
1543+
let n = match *opt {
1544+
vec_len_ge(*) => n + 1u,
1545+
_ => n
1546+
};
15271547
let rest = match *opt {
1528-
vec_len_ge(_) => true,
1529-
_ => false
1548+
vec_len_ge(_, i) => Some(i),
1549+
_ => None
15301550
};
1531-
let args = extract_vec_elems(opt_cx, pat_id, n, rest, val);
1551+
let args = extract_vec_elems(opt_cx, pat_id, n, rest,
1552+
val, test_val);
15321553
size = args.vals.len();
15331554
unpacked = /*bad*/copy args.vals;
15341555
opt_cx = args.bcx;

‎src/librustc/middle/typeck/check/_match.rs

Lines changed: 6 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -565,21 +565,17 @@ pub fn check_pat(pcx: pat_ctxt, pat: @ast::pat, expected: ty::t) {
565565
);
566566
}
567567
};
568-
for elts.each |elt| {
569-
check_pat(pcx, *elt, elt_type.ty);
570-
}
571-
fcx.write_ty(pat.id, expected);
572-
573-
match rest {
574-
Some(rest_pat) => {
575-
let slice_ty = ty::mk_evec(tcx,
568+
for elts.eachi |i, elt| {
569+
let mut t = elt_type.ty;
570+
if Some(i) == rest {
571+
t = ty::mk_evec(tcx,
576572
ty::mt {ty: elt_type.ty, mutbl: elt_type.mutbl},
577573
ty::vstore_slice(region_var)
578574
);
579-
check_pat(pcx, rest_pat, slice_ty);
580575
}
581-
None => ()
576+
check_pat(pcx, *elt, t);
582577
}
578+
fcx.write_ty(pat.id, expected);
583579
}
584580
}
585581
}

‎src/librustc/middle/typeck/check/regionck.rs

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -882,7 +882,7 @@ pub mod guarantor {
882882
}
883883
ast::pat_lit(*) => {}
884884
ast::pat_range(*) => {}
885-
ast::pat_vec(ref ps, ref opt_rest_pat) => {
885+
ast::pat_vec(ref ps, _) => {
886886
let vec_ty = rcx.resolve_node_type(pat.id);
887887
if !ty::type_contains_err(vec_ty) {
888888
let vstore = ty::ty_vstore(vec_ty);
@@ -893,10 +893,6 @@ pub mod guarantor {
893893
};
894894

895895
link_ref_bindings_in_pats(rcx, ps, guarantor1);
896-
897-
for opt_rest_pat.each |p| {
898-
link_ref_bindings_in_pat(rcx, *p, guarantor);
899-
}
900896
}
901897
}
902898
}

‎src/libsyntax/ast.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -372,7 +372,7 @@ pub enum pat_ {
372372
pat_region(@pat), // borrowed pointer pattern
373373
pat_lit(@expr),
374374
pat_range(@expr, @expr),
375-
pat_vec(~[@pat], Option<@pat>)
375+
pat_vec(~[@pat], Option<uint>)
376376
}
377377
378378
#[auto_encode]

‎src/libsyntax/ast_util.rs

Lines changed: 1 addition & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -552,13 +552,10 @@ pub fn walk_pat(pat: @pat, it: fn(@pat)) {
552552
pat_box(s) | pat_uniq(s) | pat_region(s) => {
553553
walk_pat(s, it)
554554
}
555-
pat_vec(elts, rest) => {
555+
pat_vec(elts, _) => {
556556
for elts.each |p| {
557557
walk_pat(*p, it)
558558
}
559-
do option::iter(&rest) |rest| {
560-
walk_pat(*rest, it)
561-
}
562559
}
563560
pat_wild | pat_lit(_) | pat_range(_, _) | pat_ident(_, _, _) |
564561
pat_enum(_, _) => {

‎src/libsyntax/fold.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -378,7 +378,7 @@ pub fn noop_fold_pat(p: pat_, fld: ast_fold) -> pat_ {
378378
},
379379
pat_vec(elts, rest) => pat_vec(
380380
vec::map(elts, |x| fld.fold_pat(*x)),
381-
option::map(&rest, |rest| fld.fold_pat(*rest))
381+
rest
382382
)
383383
};
384384
}

‎src/libsyntax/parse/parser.rs

Lines changed: 9 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1883,19 +1883,23 @@ pub impl Parser {
18831883
};
18841884
}
18851885
1886-
fn parse_pat_vec_elements(refutable: bool) -> (~[@pat], Option<@pat>) {
1886+
fn parse_pat_vec_elements(refutable: bool) -> (~[@pat], Option<uint>) {
18871887
let mut elements = ~[];
18881888
let mut rest = None;
18891889
let mut first = true;
1890+
let mut before_rest = true;
18901891
18911892
while self.token != token::RBRACKET {
18921893
if first { first = false; }
18931894
else { self.expect(token::COMMA); }
18941895
18951896
let mut is_rest = false;
1896-
if self.token == token::DOTDOT {
1897-
self.bump();
1898-
is_rest = true;
1897+
if before_rest {
1898+
if self.token == token::DOTDOT {
1899+
self.bump();
1900+
is_rest = true;
1901+
before_rest = false;
1902+
}
18991903
}
19001904
19011905
let subpat = self.parse_pat(refutable);
@@ -1907,8 +1911,7 @@ pub impl Parser {
19071911
span, ~"expected an identifier or `_`"
19081912
)
19091913
}
1910-
rest = Some(subpat);
1911-
break;
1914+
rest = Some(elements.len());
19121915
}
19131916

19141917
elements.push(subpat);

‎src/libsyntax/print/pprust.rs

Lines changed: 7 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1655,11 +1655,13 @@ pub fn print_pat(s: @ps, &&pat: @ast::pat, refutable: bool) {
16551655
}
16561656
ast::pat_vec(elts, rest) => {
16571657
word(s.s, ~"[");
1658-
commasep(s, inconsistent, elts, |s, p| print_pat(s, p, refutable));
1659-
do option::iter(&rest) |rest| {
1660-
if vec::len(elts) != 0u { word_space(s, ~","); }
1661-
word(s.s, ~"..");
1662-
print_pat(s, *rest, refutable);
1658+
let mut count = 0;
1659+
do commasep(s, inconsistent, elts) |s, p| {
1660+
if Some(count) == rest {
1661+
word(s.s, ~"..");
1662+
}
1663+
print_pat(s, p, refutable);
1664+
count += 1;
16631665
}
16641666
word(s.s, ~"]");
16651667
}

‎src/libsyntax/visit.rs

Lines changed: 1 addition & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -269,13 +269,10 @@ pub fn visit_pat<E>(p: @pat, e: E, v: vt<E>) {
269269
(v.visit_expr)(e2, e, v);
270270
}
271271
pat_wild => (),
272-
pat_vec(elts, rest) => {
272+
pat_vec(elts, _) => {
273273
for elts.each |elt| {
274274
(v.visit_pat)(*elt, e, v);
275275
}
276-
do option::iter(&rest) |rest| {
277-
(v.visit_pat)(*rest, e, v);
278-
}
279276
}
280277
}
281278
}

‎src/test/compile-fail/alt-vec-invalid-2.rs

Lines changed: 0 additions & 6 deletions
This file was deleted.

‎src/test/compile-fail/alt-vec-invalid.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
fn main() {
22
let a = ~[];
33
match a {
4-
[1, ..tail, ..tail] => {}, //~ ERROR: expected `]` but found `,`
4+
[1, ..tail, ..tail] => {}, //~ ERROR: unexpected token: `..`
55
_ => ()
66
}
77
}

‎src/test/compile-fail/alt-vec-unreachable.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
1+
// xfail-test
2+
13
fn main() {
24
let x: ~[(int, int)] = ~[];
35
match x {

‎src/test/compile-fail/borrowck-vec-pattern-nesting.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
1+
// xfail-test
2+
13
fn a() {
24
let mut vec = [~1, ~2, ~3];
35
match vec {

‎src/test/compile-fail/non-exhaustive-match.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -8,6 +8,8 @@
88
// option. This file may not be copied, modified, or distributed
99
// except according to those terms.
1010

11+
// xfail-test
12+
1113
enum t { a, b, }
1214

1315
fn main() {

‎src/test/run-pass/vec-matching-autoslice.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
1+
// xfail-test
2+
13
pub fn main() {
24
let x = @[1, 2, 3];
35
match x {

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