🪲 Add support for numbers in return statements (#5414)

Fixes #5170
With this PR, `return` statements try to convert their output to integers and floats and output strings if the number conversion fails. This change is required because the output of a function cannot be used in an arithmetic operation.

**How to test**
Navigate to level 14 and run the following program. Ensure that it completes without an error:
```
define round with x
    return x

r = call round with 1
print r + 1
```

hedy.py

@@ -2425,7 +2425,14 @@ def call(self, meta, args):
     def returns(self, meta, args):
         argument_string = self.print_ask_args(meta, args)
         exception = self.make_index_error_check_if_list(args)
-        return exception + f"return f'''{argument_string}'''"
+        return exception + textwrap.dedent(f"""\
+            try:
+              return int(f'''{argument_string}''')
+            except ValueError:
+              try:
+                return float(f'''{argument_string}''')
+              except ValueError:
+                return f'''{argument_string}'''""")
 
     def number(self, meta, args):
         # try all ints? return ints

tests/Tester.py

@@ -502,6 +502,17 @@ def value_exception_transpiled():
     def index_exception_transpiled():
         return '"""Runtime Index Error"""'
 
+    @staticmethod
+    def return_transpiled(arg):
+        return textwrap.dedent(f"""\
+        try:
+          return int(f'''{arg}''')
+        except ValueError:
+          try:
+            return float(f'''{arg}''')
+          except ValueError:
+            return f'''{arg}'''""")
+
     # Used to overcome indentation issues when the above code is inserted
     # in test cases which use different indentation style (e.g. 2 or 4 spaces)
 

tests/test_level/test_level_12.py

@@ -2403,10 +2403,10 @@ def test_function_use(self):
 
         print call func with 1, 2""")
 
-        expected = textwrap.dedent(f"""\
-        def func(n1, n2):
-          return f'''{{{self.addition_transpiled('n1', 'n2')}}}'''
-        print(f'''{{func(1, 2)}}''')""")
+        expected = self.dedent(
+            "def func(n1, n2):",
+            (self.return_transpiled(f"{{{self.addition_transpiled('n1', 'n2')}}}"), '  '),
+            "print(f'''{func(1, 2)}''')")
 
         self.multi_level_tester(
             code=code,
@@ -2444,10 +2444,31 @@ def test_function_use_builtin_name(self):
 
         print call sum with 1, 2""")
 
-        expected = textwrap.dedent(f"""\
-        def sum(n1, n2):
-          return f'''{{{self.addition_transpiled('n1', 'n2')}}}'''
-        print(f'''{{sum(1, 2)}}''')""")
+        expected = self.dedent(
+            "def sum(n1, n2):",
+            (self.return_transpiled(f"{{{self.addition_transpiled('n1', 'n2')}}}"), '  '),
+            "print(f'''{sum(1, 2)}''')")
+
+        self.multi_level_tester(
+            code=code,
+            max_level=16,
+            skip_faulty=False,
+            expected=expected
+        )
+
+    def test_function_returns_number(self):
+        code = textwrap.dedent("""\
+        define func with n1, n2
+            return n1 + n2
+
+        a = call func with 1, 2
+        print a + 3""")
+
+        expected = self.dedent(
+            "def func(n1, n2):",
+            (self.return_transpiled(f"{{{self.addition_transpiled('n1', 'n2')}}}"), '  '),
+            "a = func(1, 2)",
+            f"print(f'''{{{self.addition_transpiled('a', '3')}}}''')")
 
         self.multi_level_tester(
             code=code,
@@ -2516,24 +2537,6 @@ def test_addition(self):
             expected=expected
         )
 
-    def test_return_values(self):
-        code = textwrap.dedent("""\
-        define func with n1, n2
-            return n1 + n2
-
-        print call func with 1, 2""")
-
-        expected = textwrap.dedent(f"""\
-        def func(n1, n2):
-          return f'''{{{self.addition_transpiled('n1', 'n2')}}}'''
-        print(f'''{{func(1, 2)}}''')""")
-
-        self.single_level_tester(
-            code=code,
-            skip_faulty=False,
-            expected=expected
-        )
-
     def test_source_map(self):
         code = textwrap.dedent("""\
         price = 0.0

tests/test_level/test_level_14.py

@@ -451,38 +451,40 @@ def test_simple_function(self):
         print ""
         call test_function_3 with 6""")
 
-        expected = textwrap.dedent(f"""\
-        def test_function_1():
-          _int = 1
-          return f'''Test function {{_int}}'''
-        def test_function_2(_int):
-          return f'''Test function {{_int}}'''
-        def test_function_3(_input):
-          if convert_numerals('Latin', _input)!=convert_numerals('Latin', 5):
-            print(f'''NE5''')
-          if convert_numerals('Latin', _input)<convert_numerals('Latin', 5):
-            print(f'''LT5''')
-          if convert_numerals('Latin', _input)<=convert_numerals('Latin', 5):
-            print(f'''LTE5''')
-          if convert_numerals('Latin', _input)>convert_numerals('Latin', 5):
-            print(f'''GT5''')
-          if convert_numerals('Latin', _input)>=convert_numerals('Latin', 5):
-            print(f'''GTE5''')
-          if convert_numerals('Latin', _input) == convert_numerals('Latin', '5'):
-            print(f'''E5''')
-        print(f'''{{test_function_1()}}''')
-        print(f'''{{test_function_2(2)}}''')
-        m = 3
-        print(f'''{{test_function_2(m)}}''')
-        print(f'''{{test_function_2(4.0)}}''')
-        print(f'''{{test_function_2('5')}}''')
-        print(f'''{{test_function_2({self.number_cast_transpiled('1.5')} * {self.number_cast_transpiled('4')})}}''')
-        print(f'''''')
-        test_function_3(4)
-        print(f'''''')
-        test_function_3(5)
-        print(f'''''')
-        test_function_3(6)""")
+        expected = self.dedent(
+            """\
+            def test_function_1():
+              _int = 1""",
+            (self.return_transpiled(f"Test function {{_int}}"), '  '),
+            "def test_function_2(_int):",
+            (self.return_transpiled(f"Test function {{_int}}"), '  '),
+            f"""\
+            def test_function_3(_input):
+              if convert_numerals('Latin', _input)!=convert_numerals('Latin', 5):
+                print(f'''NE5''')
+              if convert_numerals('Latin', _input)<convert_numerals('Latin', 5):
+                print(f'''LT5''')
+              if convert_numerals('Latin', _input)<=convert_numerals('Latin', 5):
+                print(f'''LTE5''')
+              if convert_numerals('Latin', _input)>convert_numerals('Latin', 5):
+                print(f'''GT5''')
+              if convert_numerals('Latin', _input)>=convert_numerals('Latin', 5):
+                print(f'''GTE5''')
+              if convert_numerals('Latin', _input) == convert_numerals('Latin', '5'):
+                print(f'''E5''')
+            print(f'''{{test_function_1()}}''')
+            print(f'''{{test_function_2(2)}}''')
+            m = 3
+            print(f'''{{test_function_2(m)}}''')
+            print(f'''{{test_function_2(4.0)}}''')
+            print(f'''{{test_function_2('5')}}''')
+            print(f'''{{test_function_2({self.number_cast_transpiled('1.5')} * {self.number_cast_transpiled('4')})}}''')
+            print(f'''''')
+            test_function_3(4)
+            print(f'''''')
+            test_function_3(5)
+            print(f'''''')
+            test_function_3(6)""")
 
         output = textwrap.dedent("""\
         Test function 1