Fix example cases.

Author: Matthieu Ancellin

labelled_functions/decorators.py

@@ -2,6 +2,7 @@
 # coding: utf-8
 """Some higher-order functions that make useful tools."""
 
+from labelled_functions.abstract import Unknown
 from labelled_functions.labels import label, LabelledFunction
 
 
@@ -19,12 +20,13 @@ def func_returning_inputs(*args, **kwargs):
         func_returning_inputs,
         name=f"{func.name}",
         input_names=func.input_names,
-        output_names=func.input_names + func.output_names,
+        output_names=func.input_names + func.output_names if func.output_names is not Unknown else Unknown,
         default_values=func.default_values,
     )
 
     return func_returning_inputs
 
+
 def time(func):
     func = label(func)
 

labelled_functions/labels.py

@@ -9,7 +9,7 @@
 
 import parso
 
-from .abstract import Unknown, AbstractLabelledCallable
+from labelled_functions.abstract import Unknown, AbstractLabelledCallable
 
 
 # API
@@ -106,7 +106,7 @@ def __init__(self,
                               if p[name].default is not Parameter.empty}
 
         # OUTPUT
-        if output_names is Unknown:
+        if output_names is Unknown and function.__name__ != "<lambda>":
             try:
                 source = getsource(function)
                 output_names = _get_output_names_from_source(source)

test/test_labels.py

@@ -4,6 +4,7 @@
 import pytest
 from copy import copy
 
+from labelled_functions.abstract import Unknown
 from labelled_functions.labels import LabelledFunction, label
 from labelled_functions.decorators import keeping_inputs
 
@@ -54,6 +55,11 @@ def f(self, x):
     assert lab_f(A(), x=2) == 14
 
 
+def test_lambda():
+    ld = label(lambda foo: 2*foo)
+    assert ld.input_names == ["foo"]
+    assert ld.output_names is Unknown
+
 def test_output_checking():
     la = LabelledFunction(add, output_names=['shrubbery'])
     assert la._has_never_been_run