| author |  Dominic <4678790+dweiller@users.noreply.github.com> 2023-11-07 20:19:59+11:00 |
| committer |  Veikka Tuominen <git@vexu.eu> 2023-11-07 17:01:32+02:00 |
| log | 81219586bc3d41cc462cd383269e06c069ab8004 |
| tree | f7ea086747b95c923580c55870aead0877167437 |
| parent | 03abac382457e071540314d050e21799b59b1d5b |
sema: allow slicing [*]T without end
3 files changed, 41 insertions(+), 2 deletions(-)
doc/langref.html.in+5-1
| ... | ... | @@ -2649,7 +2649,7 @@ test "Conversion between vectors, arrays, and slices" { |
| 2649 | 2649 | <li>{#syntax#}[*]T{#endsyntax#} - many-item pointer to unknown number of items. |
| 2650 | 2650 | <ul> |
| 2651 | 2651 | <li>Supports index syntax: {#syntax#}ptr[i]{#endsyntax#}</li> |
| 2652 | <li>Supports slice syntax: {#syntax#}ptr[start..end]{#endsyntax#}</li> | |
| 2652 | <li>Supports slice syntax: {#syntax#}ptr[start..end]{#endsyntax#} and {#syntax#}ptr[start..]{#endsyntax#}</li> | |
| 2653 | 2653 | <li>Supports pointer arithmetic: {#syntax#}ptr + x{#endsyntax#}, {#syntax#}ptr - x{#endsyntax#}</li> |
| 2654 | 2654 | <li>{#syntax#}T{#endsyntax#} must have a known size, which means that it cannot be |
| 2655 | 2655 | {#syntax#}anyopaque{#endsyntax#} or any other {#link|opaque type|opaque#}.</li> |
| ... | ... | @@ -2724,6 +2724,10 @@ test "pointer arithmetic with many-item pointer" { |
| 2724 | 2724 | try expect(ptr[0] == 1); |
| 2725 | 2725 | ptr += 1; |
| 2726 | 2726 | try expect(ptr[0] == 2); |
| 2727 | ||
| 2728 | // slicing a many-item pointer without an end is equivalent to | |
| 2729 | // pointer arithmetic: `ptr[start..] == ptr + start` | |
| 2730 | try expect(ptr[1..] == ptr + 1); | |
| 2727 | 2731 | } |
| 2728 | 2732 | |
| 2729 | 2733 | test "pointer arithmetic with slices" { |
src/Sema.zig+1-1
| ... | ... | @@ -32182,7 +32182,7 @@ fn analyzeSlice( |
| 32182 | 32182 | break :e try sema.coerce(block, Type.usize, uncasted_end, end_src); |
| 32183 | 32183 | } else break :e try sema.coerce(block, Type.usize, uncasted_end_opt, end_src); |
| 32184 | 32184 | } |
| 32185 | return sema.fail(block, src, "slice of pointer must include end value", .{}); | |
| 32185 | return sema.analyzePtrArithmetic(block, src, ptr, start, .ptr_add, ptr_src, start_src); | |
| 32186 | 32186 | }; |
| 32187 | 32187 | |
| 32188 | 32188 | const sentinel = s: { |
test/behavior/slice.zig+35
| ... | ... | @@ -348,6 +348,41 @@ test "@ptrCast slice to pointer" { |
| 348 | 348 | try comptime S.doTheTest(); |
| 349 | 349 | } |
| 350 | 350 | |
| 351 | test "slice multi-pointer without end" { | |
| 352 | const S = struct { | |
| 353 | fn doTheTest() !void { | |
| 354 | try testPointer(); | |
| 355 | try testPointerZ(); | |
| 356 | } | |
| 357 | ||
| 358 | fn testPointer() !void { | |
| 359 | var array = [5]u8{ 1, 2, 3, 4, 5 }; | |
| 360 | var pointer: [*]u8 = &array; | |
| 361 | var slice = pointer[1..]; | |
| 362 | try comptime expect(@TypeOf(slice) == [*]u8); | |
| 363 | try expect(slice[0] == 2); | |
| 364 | try expect(slice[1] == 3); | |
| 365 | } | |
| 366 | ||
| 367 | fn testPointerZ() !void { | |
| 368 | var array = [5:0]u8{ 1, 2, 3, 4, 5 }; | |
| 369 | var pointer: [*:0]u8 = &array; | |
| 370 | ||
| 371 | try comptime expect(@TypeOf(pointer[1..3]) == *[2]u8); | |
| 372 | try comptime expect(@TypeOf(pointer[1..3 :4]) == *[2:4]u8); | |
| 373 | try comptime expect(@TypeOf(pointer[1..5 :0]) == *[4:0]u8); | |
| 374 | ||
| 375 | var slice = pointer[1..]; | |
| 376 | try comptime expect(@TypeOf(slice) == [*:0]u8); | |
| 377 | try expect(slice[0] == 2); | |
| 378 | try expect(slice[1] == 3); | |
| 379 | } | |
| 380 | }; | |
| 381 | ||
| 382 | try S.doTheTest(); | |
| 383 | try comptime S.doTheTest(); | |
| 384 | } | |
| 385 | ||
| 351 | 386 | test "slice syntax resulting in pointer-to-array" { |
| 352 | 387 | if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO |
| 353 | 388 | if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO |