mutex unlock

✓ Passing This code compiles and runs correctly.

Code

// The World in Koru — entry 4.
// Doorway: Go's `mu.Lock(); defer mu.Unlock()` — the canonical use of defer:
// take a lock and schedule its release at scope exit, so it runs no matter
// which path the function takes.
//
// Here in Koru you go one better: you don't write the release at all. `lock`
// mints a token whose TYPE carries the `<held!>` obligation, and `unlock` is
// the only event that consumes `<!held>`. If you never call it, the compiler
// AUTO-INSERTS the unlock at scope exit — Koru writes your `defer` for you, and
// you cannot leak the lock. When two locks are held, the inserted releases
// unwind LIFO (inner released first) — the same order `defer` guarantees, for
// the same reason: an inner resource may depend on the outer still being live.
//
// A mutex is a SYMMETRIC resource: its lifecycle is held -> released, with the
// real work happening on the state the lock guards (orthogonal to the token).
// So `lock`/`unlock` is the honest model — no invented middle state.
import std/io

pub tor lock { name: string } -> string<held!>
lock -> name

pub tor unlock { name: string<!held> }
unlock = std/io:print.ln("unlock {{ name:s }}")

// Two locks held; NO explicit unlock written. Auto-discharge inserts both at
// scope exit, LIFO: inner released before outer.
lock(name: "outer"): outer |> lock(name: "inner"): inner |> std/io:print.ln("critical section")

input.k

Actual

critical section
unlock inner
unlock outer

Expected output

✓ Zig✓ C#

critical section
unlock inner
unlock outer

Emitted Zig source

// Access compiler flags via the per-user compiler_env module
const CompilerEnv = @import("compiler_env").CompilerEnv;

pub const panic = if (@import("builtin").mode == .Debug)
    @import("std").debug.FullPanic(@import("std").debug.defaultPanic)
else
    @import("std").debug.simple_panic;


const __koru_bare = struct {
    extern fn posix_memalign(memptr: *?*anyopaque, alignment: usize, size: usize) c_int;
    extern fn free(ptr: ?*anyopaque) void;
    fn bareAlloc(_: *anyopaque, len: usize, alignment: @import("std").mem.Alignment, _: usize) ?[*]u8 {
        var p: ?*anyopaque = null;
        const a = @max(alignment.toByteUnits(), @sizeOf(usize));
        if (posix_memalign(&p, a, len) != 0) return null;
        return @ptrCast(p);
    }
    fn bareResize(_: *anyopaque, _: []u8, _: @import("std").mem.Alignment, _: usize, _: usize) bool { return false; }
    fn bareRemap(_: *anyopaque, _: []u8, _: @import("std").mem.Alignment, _: usize, _: usize) ?[*]u8 { return null; }
    fn bareFree(_: *anyopaque, memory: []u8, _: @import("std").mem.Alignment, _: usize) void { free(@ptrCast(memory.ptr)); }
    const vtable = @import("std").mem.Allocator.VTable{ .alloc = bareAlloc, .resize = bareResize, .remap = bareRemap, .free = bareFree };
    const allocator = @import("std").mem.Allocator{ .ptr = undefined, .vtable = &vtable };
};
const __koru_backing = if (@import("builtin").link_libc) @import("std").heap.c_allocator else if (@import("builtin").os.tag == .freestanding) __koru_bare.allocator else @import("std").heap.page_allocator;
var __koru_leak_count: @import("std").atomic.Value(usize) = .init(0);
fn __koru_alloc(ctx: *anyopaque, len: usize, alignment: @import("std").mem.Alignment, ret_addr: usize) ?[*]u8 {
    _ = ctx;
    const r = __koru_backing.rawAlloc(len, alignment, ret_addr);
    if (comptime @import("builtin").mode == .Debug) {
        if (r != null) _ = __koru_leak_count.fetchAdd(1, .monotonic);
    }
    return r;
}
fn __koru_resize(ctx: *anyopaque, memory: []u8, alignment: @import("std").mem.Alignment, new_len: usize, ret_addr: usize) bool {
    _ = ctx;
    return __koru_backing.rawResize(memory, alignment, new_len, ret_addr);
}
fn __koru_remap(ctx: *anyopaque, memory: []u8, alignment: @import("std").mem.Alignment, new_len: usize, ret_addr: usize) ?[*]u8 {
    _ = ctx;
    return __koru_backing.rawRemap(memory, alignment, new_len, ret_addr);
}
fn __koru_free(ctx: *anyopaque, memory: []u8, alignment: @import("std").mem.Alignment, ret_addr: usize) void {
    _ = ctx;
    __koru_backing.rawFree(memory, alignment, ret_addr);
    if (comptime @import("builtin").mode == .Debug) {
        _ = __koru_leak_count.fetchSub(1, .monotonic);
    }
}
const __koru_vtable = @import("std").mem.Allocator.VTable{ .alloc = __koru_alloc, .resize = __koru_resize, .remap = __koru_remap, .free = __koru_free };
pub fn koru_allocator() @import("std").mem.Allocator {
    return .{ .ptr = undefined, .vtable = &__koru_vtable };
}

pub inline fn __koru_intcast(comptime T: type, x: anytype) T {
    if (comptime (@import("builtin").mode == .Debug or @import("builtin").mode == .ReleaseSafe))
        return @as(T, @intCast(x));
    const dst = @typeInfo(T);
    const src = @typeInfo(@TypeOf(x));
    if (comptime (dst == .int and src == .int and dst.int.bits == src.int.bits and dst.int.signedness != src.int.signedness))
        return @as(T, @bitCast(x));
    return @as(T, @intCast(x));
}

pub fn koru_leak_check() void {
    if (comptime @import("builtin").mode != .Debug) return;
    if (__koru_leak_count.load(.acquire) == 0) return;
    if (comptime @import("builtin").target.os.tag == .freestanding) {
        if (comptime @import("builtin").cpu.arch == .wasm32 or @import("builtin").cpu.arch == .wasm64) {
            @panic("KORU LEAK CHECK FAILED: the produced program leaked");
        } else {
            const __klc = struct { extern var stdout: ?*anyopaque; extern fn fputs(__s: [*:0]const u8, __st: ?*anyopaque) c_int; };
            var __lb: [128]u8 = undefined;
            const __lm = "KORU LEAK CHECK FAILED: allocations still outstanding at end of run: ";
            @memcpy(__lb[0..__lm.len], __lm);
            var __ln: usize = __lm.len;
            var __lv = __koru_leak_count.load(.acquire);
            var __ld: [20]u8 = undefined;
            var __lk: usize = 0;
            while (__lv > 0) : (__lk += 1) { __ld[__lk] = @intCast('0' + __lv % 10); __lv /= 10; }
            for (0..__lk) |__li| { __lb[__ln] = __ld[__lk - 1 - __li]; __ln += 1; }
            __lb[__ln] = '\n'; __ln += 1; __lb[__ln] = 0;
            _ = __klc.fputs(@as([*:0]const u8, @ptrCast(&__lb)), __klc.stdout);
            @trap();
        }
    } else {
        @import("std").debug.print("KORU LEAK CHECK FAILED: the produced program leaked (trace above)\n", .{});
        @import("std").process.exit(1);
    }
}

pub const main_module = struct {
    pub const lock_event = struct {
        pub const Input = struct {
            name: []const u8,
        };
        pub const Output = []const u8;
        pub fn handler(__koru_event_input: @This().Input) @This().Output {
            const name = __koru_event_input.name;
            _ = &name;
            return name;
        }
    };
    pub const unlock_event = struct {
        pub const Input = struct {
            name: []const u8,
        };
        pub const Output = void;
        pub fn handler(__koru_event_input: @This().Input) @This().Output {
            // >>> SUBFLOW: tests/regression/830_THE_WORLD/834_mutex_unlock/input.k:24
            const name = __koru_event_input.name;
            _ = &name;
            _ = &__koru_event_input;
            (struct { fn __kout(__fd: i32, __b: []const u8) void { if (@import("builtin").os.tag == .freestanding) { const __kc = struct { extern var stdout: ?*anyopaque; extern var stderr: ?*anyopaque; extern fn fputs(__s: [*:0]const u8, __st: ?*anyopaque) c_int; }; var __kt: [4096]u8 = undefined; for (0..(__b.len + __kt.len - 2) / (__kt.len - 1)) |__ki| { const __kn = @min(__kt.len - 1, __b.len - __ki * (__kt.len - 1)); @memcpy(__kt[0..__kn], __b[__ki * (__kt.len - 1)..][0..__kn]); __kt[__kn] = 0; @import("std").mem.doNotOptimizeAway(__kc.fputs(@as([*:0]const u8, @ptrCast(&__kt)), if (__fd == 2) __kc.stderr else __kc.stdout)); } } else { @import("std").mem.doNotOptimizeAway(@import("std").posix.write(__fd, __b) catch @as(usize, 0)); } } fn __kw(comptime __f: []const u8, __a: anytype) void { var __kb: [65536]u8 = undefined; const __ks = @import("std").fmt.bufPrint(&__kb, __f, __a) catch __kb[0..0]; __kout(1, __ks); } }).__kw("unlock {s}\n", .{name});
        }
    };
    // >>> FLOW: tests/regression/830_THE_WORLD/834_mutex_unlock/input.k:28  ~input:lock()
    pub fn flow0() void {
        const outer: []const u8 = blk: {
            break :blk "outer";
        };
        const inner: []const u8 = blk: {
            break :blk "inner";
        };
        _ = &inner;
        (struct { fn __kout(__fd: i32, __b: []const u8) void { if (@import("builtin").os.tag == .freestanding) { const __kc = struct { extern var stdout: ?*anyopaque; extern var stderr: ?*anyopaque; extern fn fputs(__s: [*:0]const u8, __st: ?*anyopaque) c_int; }; var __kt: [4096]u8 = undefined; for (0..(__b.len + __kt.len - 2) / (__kt.len - 1)) |__ki| { const __kn = @min(__kt.len - 1, __b.len - __ki * (__kt.len - 1)); @memcpy(__kt[0..__kn], __b[__ki * (__kt.len - 1)..][0..__kn]); __kt[__kn] = 0; @import("std").mem.doNotOptimizeAway(__kc.fputs(@as([*:0]const u8, @ptrCast(&__kt)), if (__fd == 2) __kc.stderr else __kc.stdout)); } } else { @import("std").mem.doNotOptimizeAway(@import("std").posix.write(__fd, __b) catch @as(usize, 0)); } } fn __kw(comptime __f: []const u8, __a: anytype) void { var __kb: [65536]u8 = undefined; const __ks = @import("std").fmt.bufPrint(&__kb, __f, __a) catch __kb[0..0]; __kout(1, __ks); } }).__kw("critical section\n", .{});
        const result_2 = main_module.unlock_event.handler(.{ .name = inner });
        _ = &result_2;
        _ = main_module.unlock_event.handler(.{ .name = outer });
    }
    pub fn koru_start_flow() void {
        const result_0 = koru_koru.start_event.handler(.{  });
        const result_0_done = result_0.done;
        _ = &result_0_done;
    }
    pub fn koru_end_flow() void {
        const result_0 = koru_koru.end_event.handler(.{  });
        const result_0_done = result_0.done;
        _ = &result_0_done;
    }
};

pub const koru_koru = struct {
    pub const start_event = struct {
        pub const Input = struct {
        };
        pub const Output = union(enum(u8)) {
            done: struct {
            },
        };
        pub fn handler(__koru_event_input: @This().Input) @This().Output {
            _ = &__koru_event_input;
            return .{ .done = .{} };
        }
    };
    pub const end_event = struct {
        pub const Input = struct {
        };
        pub const Output = union(enum(u8)) {
            done: struct {
            },
        };
        pub fn handler(__koru_event_input: @This().Input) @This().Output {
            _ = &__koru_event_input;
            return .{ .done = .{} };
        }
    };
};
pub fn main() void {
    main_module.koru_start_flow();
    main_module.flow0();
    main_module.koru_end_flow();
    if (comptime @import("builtin").mode == .Debug) koru_leak_check();
}

test {
    @import("std").testing.refAllDeclsRecursive(@This());
}

Emitted C# source

static class main_module {
  public static void __koru_stdout_write(dynamic s) => global::System.Console.Out.Write(s);
  public static void __koru_stderr_write(dynamic s) => global::System.Console.Error.Write(s);
  // The mutable handle carrier — `*String`-style resources are
  // `new __KoruBox { data = … }` because C# anonymous types are
  // read-only: `s.data = …` (std/string append/clear, handle
  // mutation generally) needs a settable member.
  public class __KoruBox { public dynamic data; }
  // Textification for `{{ … }}` operands: C# bool ToStrings as
  // `True` where Koru prints `true`, and the operand's static type
  // is unknown at this boundary — a `(x) is bool` inline test would
  // be a compile error on statically-typed operands instead. Generic
  // on purpose: `dynamic` boxed every value-type operand — measured
  // ~1s/10M elements on 012_threat_scanner — while T specializes to
  // the operand's own ToString() with no box.
  public static string __koru_str<T>(T v) => v is bool b ? (b ? "true" : "false") : v?.ToString();
  public static class lock_event {
    public struct Input {
      public string name;
    }
    public static string handler(Input __koru_input) {
      var name = __koru_input.name;
      return (string)(name);
    }
  }
  public static class unlock_event {
    public struct Input {
      public string name;
    }
    public static dynamic handler(Input __koru_input) {
      var name = __koru_input.name;
__koru_stdout_write("unlock " + __koru_str(name) + "\n");

      return default;

    }
  }
  public static class koru_start_event {
    public struct Input {
    }
    public struct Output {
      public string tag;
      public dynamic done;
    }
    public static Output handler(Input __koru_input) => new Output { tag = "done" };
  }
  public static class koru_end_event {
    public struct Input {
    }
    public struct Output {
      public string tag;
      public dynamic done;
    }
    public static Output handler(Input __koru_input) => new Output { tag = "done" };
  }
  public static void flow0() {
    var outer = main_module.lock_event.handler(new lock_event.Input { name = (string)("outer")});
    var inner = main_module.lock_event.handler(new lock_event.Input { name = (string)("inner")});
__koru_stdout_write("critical section" + "\n");
    main_module.unlock_event.handler(new unlock_event.Input { name = (string)(inner)});
    main_module.unlock_event.handler(new unlock_event.Input { name = (string)(outer)});
  }
  public static void flow1() {
    main_module.koru_start_event.handler(new koru_start_event.Input { });
  }
  public static void flow2() {
    main_module.koru_end_event.handler(new koru_end_event.Input { });
  }
}

static class Program {
  static void Main() {
    main_module.flow1();
    main_module.flow0();
    main_module.flow2();
  }
}

Flows

subflow ~unlock click a branch to expand · @labels scroll to their anchor

print.ln (expr: "unlock {{ name:s }}")

flow ~lock click a branch to expand · @labels scroll to their anchor

lock (name: "outer")

Test Configuration

MUST_RUN LANGUAGES: zig cs

← generator fold optional arm double unlock →