Merge pull request #10034 from Snektron/stage2-slice

stage2: slice and optional improvements

test/behavior/slice.zig

@@ -109,3 +109,60 @@ test "slice of type" {
         }
     }
 }
+
+test "generic malloc free" {
+    const a = memAlloc(u8, 10) catch unreachable;
+    memFree(u8, a);
+}
+var some_mem: [100]u8 = undefined;
+fn memAlloc(comptime T: type, n: usize) anyerror![]T {
+    return @ptrCast([*]T, &some_mem[0])[0..n];
+}
+fn memFree(comptime T: type, memory: []T) void {
+    _ = memory;
+}
+
+test "slice of hardcoded address to pointer" {
+    const S = struct {
+        fn doTheTest() !void {
+            const pointer = @intToPtr([*]u8, 0x04)[0..2];
+            comptime try expect(@TypeOf(pointer) == *[2]u8);
+            const slice: []const u8 = pointer;
+            try expect(@ptrToInt(slice.ptr) == 4);
+            try expect(slice.len == 2);
+        }
+    };
+
+    try S.doTheTest();
+}
+
+test "comptime slice of pointer preserves comptime var" {
+    comptime {
+        var buff: [10]u8 = undefined;
+        var a = @ptrCast([*]u8, &buff);
+        a[0..1][0] = 1;
+        try expect(buff[0..][0..][0] == 1);
+    }
+}
+
+test "comptime pointer cast array and then slice" {
+    const array = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8 };
+
+    const ptrA: [*]const u8 = @ptrCast([*]const u8, &array);
+    const sliceA: []const u8 = ptrA[0..2];
+
+    const ptrB: [*]const u8 = &array;
+    const sliceB: []const u8 = ptrB[0..2];
+
+    try expect(sliceA[1] == 2);
+    try expect(sliceB[1] == 2);
+}
+
+test "slicing zero length array" {
+    const s1 = ""[0..];
+    const s2 = ([_]u32{})[0..];
+    try expect(s1.len == 0);
+    try expect(s2.len == 0);
+    try expect(mem.eql(u8, s1, ""));
+    try expect(mem.eql(u32, s2, &[_]u32{}));
+}

test/behavior/slice_stage1.zig

@@ -4,15 +4,6 @@ const expectEqualSlices = std.testing.expectEqualSlices;
 const expectEqual = std.testing.expectEqual;
 const mem = std.mem;
 
-test "slicing zero length array" {
-    const s1 = ""[0..];
-    const s2 = ([_]u32{})[0..];
-    try expect(s1.len == 0);
-    try expect(s2.len == 0);
-    try expect(mem.eql(u8, s1, ""));
-    try expect(mem.eql(u32, s2, &[_]u32{}));
-}
-
 test "slice string literal has correct type" {
     comptime {
         try expect(@TypeOf("aoeu"[0..]) == *const [4:0]u8);
@@ -25,18 +16,6 @@ test "slice string literal has correct type" {
     comptime try expect(@TypeOf(array[runtime_zero..]) == []const i32);
 }
 
-test "generic malloc free" {
-    const a = memAlloc(u8, 10) catch unreachable;
-    memFree(u8, a);
-}
-var some_mem: [100]u8 = undefined;
-fn memAlloc(comptime T: type, n: usize) anyerror![]T {
-    return @ptrCast([*]T, &some_mem[0])[0..n];
-}
-fn memFree(comptime T: type, memory: []T) void {
-    _ = memory;
-}
-
 test "result location zero sized array inside struct field implicit cast to slice" {
     const E = struct {
         entries: []u32,
@@ -307,20 +286,6 @@ test "slice syntax resulting in pointer-to-array" {
     comptime try S.doTheTest();
 }
 
-test "slice of hardcoded address to pointer" {
-    const S = struct {
-        fn doTheTest() !void {
-            const pointer = @intToPtr([*]u8, 0x04)[0..2];
-            comptime try expect(@TypeOf(pointer) == *[2]u8);
-            const slice: []const u8 = pointer;
-            try expect(@ptrToInt(slice.ptr) == 4);
-            try expect(slice.len == 2);
-        }
-    };
-
-    try S.doTheTest();
-}
-
 test "type coercion of pointer to anon struct literal to pointer to slice" {
     const S = struct {
         const U = union {
@@ -352,15 +317,6 @@ test "type coercion of pointer to anon struct literal to pointer to slice" {
     comptime try S.doTheTest();
 }
 
-test "comptime slice of pointer preserves comptime var" {
-    comptime {
-        var buff: [10]u8 = undefined;
-        var a = @ptrCast([*]u8, &buff);
-        a[0..1][0] = 1;
-        try expect(buff[0..][0..][0] == 1);
-    }
-}
-
 test "array concat of slices gives slice" {
     comptime {
         var a: []const u8 = "aoeu";
@@ -370,19 +326,6 @@ test "array concat of slices gives slice" {
     }
 }
 
-test "comptime pointer cast array and then slice" {
-    const array = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8 };
-
-    const ptrA: [*]const u8 = @ptrCast([*]const u8, &array);
-    const sliceA: []const u8 = ptrA[0..2];
-
-    const ptrB: [*]const u8 = &array;
-    const sliceB: []const u8 = ptrB[0..2];
-
-    try expect(sliceA[1] == 2);
-    try expect(sliceB[1] == 2);
-}
-
 test "slice bounds in comptime concatenation" {
     const bs = comptime blk: {
         const b = "........1........";

test/behavior/slice_stage2.zig

@@ -0,0 +1,12 @@
+const std = @import("std");
+const expect = std.testing.expect;
+
+const x = @intToPtr([*]i32, 0x1000)[0..0x500];
+const y = x[0x100..];
+test "compile time slice of pointer to hard coded address" {
+    try expect(@ptrToInt(x) == 0x1000);
+    try expect(x.len == 0x500);
+
+    try expect(@ptrToInt(y) == 0x1400);
+    try expect(y.len == 0x400);
+}