012 auto discharge explicit with multiple

✓ Passing This code compiles and runs correctly.

Code

// auto-discharge with MULTIPLE disposers for the same state: `locked!` can be
// discharged by EITHER `unlock` (happy path) or `force-close` (error path).
// `write` is fallible (`| written` / `| err`); its err arm force-closes the
// lock, its success arm unlocks. Both arms discharge `locked!` — the explicit
// branch picks which disposer runs.
import app/fs

app/fs:open(path: "test.txt"): f |> app/fs:lock(file: f): l |> app/fs:write(file: l, data: "test")
        | written |> app/fs:unlock(file: l)
        | err _ |> app/fs:force-close(file: l)

input.k

Actual

Writing: test
Unlocking

Expected output

Writing: test
Unlocking

Flows

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

open (path: "test.txt")

Imported Files

// Library module: fs
// State transitions with multiple disposal options (mimics string library)

const std = @import("std");

const File = struct { handle: i32 };

// Open a file - returns opened! state
~pub tor open { path: string } -> *File<opened!>

~proc open|zig {
    const f = std.heap.page_allocator.create(File) catch unreachable;
    f.* = File{ .handle = 42 };
    return f;
}

// Lock - transition opened! -> locked!
~pub tor lock { file: *File<!opened> } -> *File<locked!>

~proc lock|zig {
    return file;
}

// Write - requires locked state (doesn't consume)
~pub tor write { file: *File<locked>, data: string }
| written
| err string

~proc write|zig {
    std.debug.print("Writing: {s}\n", .{data});
    return .{ .written = .{} };
}

// Unlock - consumes locked! (Option 1 for disposing locked!)
~pub tor unlock { file: *File<!locked> }

~proc unlock|zig {
    std.debug.print("Unlocking\n", .{});
    std.heap.page_allocator.destroy(file);
}

// Force close - also consumes locked! (Option 2 for disposing locked!)
~pub tor force-close { file: *File<!locked> }

~proc force-close|zig {
    std.debug.print("Force closing\n", .{});
    std.heap.page_allocator.destroy(file);
}

fs.kz

Test Configuration

MUST_RUN

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