Check nil literal as result and with length functor (#52)

aqua/examples/stream.aqua

@@ -28,6 +28,13 @@ func returnNil() -> *string:
     relayNil <- stringNil()
     <- relayNil
 
+func returnNilLiteral() -> *string:
+    <- nil
+
+func returnNilLength() -> u32:
+    arr = nil
+    <- arr.length
+
 func stringNone() -> ?string:
     valueNone: ?string
     <- valueNone

src/__test__/examples.spec.ts

@@ -16,6 +16,8 @@ import { parCall, testTimeoutCall } from '../examples/parCall';
 import { complexCall } from '../examples/complex';
 import { constantsCall, particleTtlAndTimestampCall } from '../examples/constantsCall';
 import {
+    nilLengthCall,
+    nilLiteralCall,
     returnNilCall,
     returnNoneCall, streamAssignmentCall,
     streamCall,
@@ -259,6 +261,16 @@ describe('Testing examples', () => {
         expect(streamResult).toEqual("333");
     })
 
+    it('stream.aqua nil literal', async () => {
+        let result = await nilLiteralCall()
+        expect(result).toEqual([]);
+    })
+
+    it('stream.aqua nil length', async () => {
+        let result = await nilLengthCall()
+        expect(result).toEqual([]);
+    })
+
     it('stream.aqua int functor', async () => {
         let streamResult = await streamIntFunctorCall()
         expect(streamResult).toEqual("123");

src/examples/streamCall.ts

@@ -1,7 +1,7 @@
 import { FluencePeer } from '@fluencelabs/fluence';
 import {
     checkStreams,
-    registerStringer,
+    registerStringer, returnNilLength, returnNilLiteral,
     returnStreamFromFunc, streamAssignment,
     streamFunctor, streamIntFunctor, streamJoin,
     stringNil,
@@ -42,6 +42,14 @@ export async function streamAssignmentCall() {
     return await streamAssignment(["333"]);
 }
 
+export async function nilLiteralCall() {
+    return await returnNilLiteral();
+}
+
+export async function nilLengthCall() {
+    return await returnNilLength();
+}
+
 export async function streamIntFunctorCall() {
     return await streamIntFunctor([0]);
 }