Recursion support - cannot write `cloud.Function` that calls itself

[Chriscbr]

I tried this:

bring cloud;
let fib = new cloud.Function(inflight (payload: str): str => {
  let n = num.fromStr(payload);
  if n < 3 {
    return "1";
  } else {
    let f1 = num.fromStr(fib("${n - 1}"));
    let f2 = num.fromStr(fib("${n - 2}"));
    return "${f1 + f2}";
  }
});

This happened:

When I compile it to the simulator:

ERROR: Cannot access 'fib' before initialization

examples/tests/valid/target/test/load_test.test.wsim.905075.tmp/.wing/preflight.js:39
         _registerOnLift(host, ops) {
           if (ops.includes("handle")) {
>>           $Closure1._registerOnLiftObject(fib, host, ["invoke"]);
           }
           super._registerOnLift(host, ops);

I expected this:

I expected the error to be caught during type checking (or miraculously for the example to compile)

Is there a workaround?

No response

Component

Compiler

Wing Version

0.41.22

Node.js Version

18.14.1

Platform(s)

MacOS

Anything else?

No response

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[Chriscbr]

If I try without wrapping the inflight closure inside cloud.Function, I get a different error:

let fib = inflight (payload: str): str => {
  let n = num.fromStr(payload);
  if n < 3 {
    return "1";
  } else {
    let f1 = num.fromStr(fib("${n - 1}"));
    let f2 = num.fromStr(fib("${n - 2}"));
    return "${f1 + f2}";
  }
};

test "fib" {
  assert(fib("10") == "55");
}

ERROR: Maximum call stack size exceeded

examples/tests/valid/target/test/load_test.test.wsim.114055.tmp/.wing/preflight.js:18
           return `
             require("./inflight.$Closure1-1.js")({
>>             $fib: ${context._lift(fib)},
               $std_Number: ${context._lift($stdlib.core.toLiftableModuleType(std.Number, "@winglang/sdk/std", "Number"))},
             })

[Chriscbr]

The only cases this works today is if the function is defined in the same phase (i.e. a preflight function defined in preflight, or an inflight function defined in inflight):

let fib = (payload: str): str => {
  let n = num.fromStr(payload);
  if n < 3 {
    return "1";
  } else {
    let f1 = num.fromStr(fib("${n - 1}"));
    let f2 = num.fromStr(fib("${n - 2}"));
    return "${f1 + f2}";
  }
};

assert(fib("10") == "55");

[github-actions[bot]]

Hi,

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