020 interpreter if e2e

// Test: interpreted `if` end to end through the surface — source with a
// condition and then/else continuations dispatches into the taken branch.

~import std/runtime
~import std/io

const std = @import("std");

~pub tor yes { result: string } -> u64

~proc yes|zig {
    std.debug.print("YES: {s}\n", .{result});
    return 1;
}

~pub tor no { result: string } -> u64

~proc no|zig {
    std.debug.print("NO: {s}\n", .{result});
    return 0;
}

~std/runtime:register(scope: "t") {
    yes(1)
    no(1)
}

const TEST_SOURCE = "if(true)\n| then |> yes(result: \"passed\")\n| else |> no(result: \"failed\")";

~std/runtime:run(source: TEST_SOURCE, scope: "t")
| result _ |> std/io:print.ln("OK")
| exhausted _ |> std/io:print.ln("EXHAUSTED")
| parse-error _ |> std/io:print.ln("PARSE ERROR")
| validation-error _ |> std/io:print.ln("VALIDATION ERROR")
| shape-error _ |> std/io:print.ln("SHAPE ERROR")
| event-denied _ |> std/io:print.ln("EVENT DENIED")
| dispatch-error _ |> std/io:print.ln("DISPATCH ERROR")
| scope-not-found _ |> std/io:print.ln("SCOPE NOT FOUND")

const TEST_SOURCE_ELSE = "if(false)\n| then |> yes(result: \"failed\")\n| else |> no(result: \"passed\")";

~std/runtime:run(source: TEST_SOURCE_ELSE, scope: "t")
| result _ |> std/io:print.ln("OK ELSE")
| exhausted _ |> std/io:print.ln("EXHAUSTED")
| parse-error _ |> std/io:print.ln("PARSE ERROR")
| validation-error _ |> std/io:print.ln("VALIDATION ERROR")
| shape-error _ |> std/io:print.ln("SHAPE ERROR")
| event-denied _ |> std/io:print.ln("EVENT DENIED")
| dispatch-error _ |> std/io:print.ln("DISPATCH ERROR")
| scope-not-found _ |> std/io:print.ln("SCOPE NOT FOUND")