✓
Passing This code compiles and runs correctly.
Code
// PIN — a `#label` fold whose implementing subflow declares UNION outputs:
// the back-edge branch loops inside `while`, the remaining arms construct the
// impl's output union after it, and the after-loop switch names the looped
// branch `unreachable` (Zig does not narrow union(enum) through the guard).
const std = @import("std");
~import std/io
~tor round { text: string, rounds: i32 }
| again { text: string, rounds: i32 }
| stop string
| broke
~proc round|zig {
if (rounds < 0) return .broke;
if (rounds <= 1) return .{ .stop = text };
return .{ .again = .{ .text = text, .rounds = rounds - 1 } };
}
~tor polish { text: string, rounds: i32 }
| polished string
| broke
~polish = #loop round(text, rounds)
| again a |> @loop(a.text, a.rounds)
| stop out => polished out
| broke => broke
~polish(text: "hi", rounds: 3)
| polished out |> std/io:print.ln("{{ out:s }}")
| broke |> std/io:print.ln("broke")
Supporting Files
~proc round|cs {
if (rounds < 0) return new Output { tag = "broke" };
if (rounds <= 1) return new Output { tag = "stop", stop = text };
return new Output { tag = "again", again = new again_payload { text = text, rounds = rounds - 1 } };
}Actual
hi
Expected output
✓ Zig✓ C#hi
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 and !@import("builtin").cpu.arch.isWasm()) __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 {
const std = @import("std");
pub const round_event = struct {
pub const Input = struct {
text: []const u8,
rounds: i32,
};
pub const Output = union(enum(u8)) {
again: struct {
text: []const u8,
rounds: i32,
},
stop: []const u8,
broke: struct {
},
};
pub fn handler(__koru_event_input: @This().Input) @This().Output {
// >>> PROC: round [tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:13]
const text = __koru_event_input.text;
const rounds = __koru_event_input.rounds;
_ = &text;
_ = &rounds;
_ = &__koru_event_input;
if (rounds < 0) return .broke;
if (rounds <= 1) return .{ .stop = text };
return .{ .again = .{ .text = text, .rounds = rounds - 1 } };
}
};
pub const polish_event = struct {
pub const Input = struct {
text: []const u8,
rounds: i32,
};
pub const Output = union(enum(u8)) {
polished: []const u8,
broke: struct {
},
};
pub fn handler(__koru_event_input: @This().Input) @This().Output {
// >>> SUBFLOW: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:23
const text = __koru_event_input.text;
const rounds = __koru_event_input.rounds;
_ = &text;
_ = &rounds;
_ = &__koru_event_input;
var loop_text: []const u8 = text;
var loop_rounds: i32 = rounds;
loop: while (true) {
const result_0 = main_module.round_event.handler(.{ .text = loop_text, .rounds = loop_rounds });
switch (result_0) {
// >>> BRANCH: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:25 | stop out |>
.stop => |out| {
return .{ .polished = out };
},
// >>> BRANCH: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:24 | again a |>
.again => |a| {
loop_text = a.text;
loop_rounds = a.rounds;
continue :loop;
},
// >>> BRANCH: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:26 | broke |>
.broke => {
return .{ .broke = .{ } };
},
}
break :loop;
}
@panic("koru: a #label fold arm in 'polish' exited the loop without a continue or a `->` produce — the handler owes a value it never made");
}
};
// >>> FLOW: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:28 ~input:polish()
pub fn flow0() void {
const result_0 = main_module.polish_event.handler(.{ .text = "hi", .rounds = 3 });
switch (result_0) {
// >>> BRANCH: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:30 | broke |>
.broke => {
(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("broke\n", .{});
},
// >>> BRANCH: tests/regression/000_CORE_LANGUAGE/040_CONTROL_FLOW/243_fold_subflow_union_outputs/input.kz:29 | polished out |>
.polished => |out| {
(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("{s}\n", .{out});
},
}
}
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(object s) => global::System.Console.Out.Write(s);
public static void __koru_stderr_write(object 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. `object`, not
// `dynamic`: the field is storage — every `x.data` read reaches
// it through a dynamic-typed handle (`*T` Input fields, the
// `dynamic` borrow locals below), so the member itself only
// needs to hold the value, and `object` keeps the DLR out of
// the store/load path.
public class __KoruBox { public object 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 round_event {
public struct Input {
public string text;
public int rounds;
}
public struct Output {
public string tag;
public again_payload again;
public string stop;
public object broke;
}
public struct again_payload {
public string text;
public int rounds;
}
public static Output handler(Input __koru_input) {
var text = __koru_input.text;
var rounds = __koru_input.rounds;
if (rounds < 0) return new Output { tag = "broke" };
if (rounds <= 1) return new Output { tag = "stop", stop = text };
return new Output { tag = "again", again = new again_payload { text = text, rounds = rounds - 1 } };
return default;
}
}
public static class polish_event {
public struct Input {
public string text;
public int rounds;
}
public struct Output {
public string tag;
public string polished;
public object broke;
}
public static Output handler(Input __koru_input) {
var text = __koru_input.text;
var rounds = __koru_input.rounds;
string looptext = text;
int looprounds = rounds;
var result_0 = main_module.round_event.handler(new round_event.Input { text = (string)(looptext), rounds = (int)(looprounds)});
__fold_loop_check:
while (result_0.tag == "again") {
var a = result_0.again;
looptext = a.text;
looprounds = a.rounds;
result_0 = main_module.round_event.handler(new round_event.Input { text = (string)(looptext), rounds = (int)(looprounds)});
goto __fold_loop_check;
}
if (result_0.tag == "stop") {
var @out = result_0.stop;
return new Output { tag = "polished", polished = @out };
}
if (result_0.tag == "broke") {
return new Output { tag = "broke" };
}
return default;
}
}
public static class koru_start_event {
public struct Input {
}
public struct Output {
public string tag;
public object 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 object done;
}
public static Output handler(Input __koru_input) => new Output { tag = "done" };
}
public static void flow0() {
var result_1 = main_module.polish_event.handler(new polish_event.Input { text = (string)("hi"), rounds = (int)(3)});
if (result_1.tag == "polished") {
var @out = result_1.polished;
__koru_stdout_write("" + __koru_str(@out) + "\n");
}
if (result_1.tag == "broke") {
__koru_stdout_write("broke" + "\n");
}
}
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 ~polish click a branch to expand · @labels scroll to their anchor
#loop round (text, rounds)
flow ~polish click a branch to expand · @labels scroll to their anchor
polish (text: "hi", rounds: 3)
Test Configuration
MUST_RUN LANGUAGES: zig cs