Add support for multiple cases, single action.

Author: mikeckennedy

README.md

@@ -37,5 +37,39 @@ def process_with_data(*value):
 * Checks for duplicate keys / cases
 * Keys can be anything hashable (numbers, strings, objects, etc.)
 * Could be extended for "fall-through" cases (doesn't yet)
+* Use range and list for multiple cases mapped to a single action
+
+## Multiple cases, one action
+
+You can map ranges and lists of cases to a single action as follows:
+
+```python
+# with lists:
+value = 4  # matches even number case
+
+with switch(value) as s:
+    s.case([1, 3, 5, 7], lambda: ...)
+    s.case([0, 2, 4, 6, 8], lambda: ...)
+    s.default(lambda: ...)
+```
+
+```python
+# with ranges:
+value = 4  # matches first case
+
+with switch(value) as s:
+    s.case(range(1, 5), lambda: ...)
+    s.case(range(6, 7), lambda: ...)
+    s.default(lambda: ...)
+```
+
+**Warning / open for debate**: 
+
+I'm a little unsure what is the right way to handle this
+On one hand, reading `case(range(1,5))` seems like it should
+include `1, 2, 3, 4, 5`. But `list(range(1,5))` is `[1,2,3,4]`. 
+So that would be inconsistent.
+
+Thoughts? I'm going with `1,2,3,4,5` for `range(1,5)` for now. 
 
 

switchlang.py

@@ -11,6 +11,16 @@ def default(self, func: Callable[[], None]):
         self.case('__default__', func)
 
     def case(self, key, func: Callable[[], None]):
+        if isinstance(key, range):
+            for n in range(key.start, key.stop + 1, key.step):
+                self.case(n, func)
+            return
+
+        if isinstance(key, list):
+            for i in key:
+                self.case(i, func)
+            return
+
         if key in self.cases:
             raise ValueError("Duplicate case: {}".format(key))
         if not func:
@@ -34,4 +44,4 @@ def __exit__(self, exc_type, exc_val, exc_tb):
         if not func:
             raise Exception("Value does not match any case and there is no default case: value {}".format(self.value))
 
-        func()
+        func()

tests/coretests.py

@@ -86,3 +86,41 @@ def test_error_duplicate_case(self):
             with switch('val') as s:
                 s.case(1, lambda: None)
                 s.case(1, lambda: None)
+
+    def test_multiple_values_one_case_range(self):
+        value = 7
+
+        executed_case = None
+
+        def get_set_case(val):
+            nonlocal executed_case
+            executed_case = val
+
+        # I'm a little unsure what is the right way to handle this
+        # On one hand, reading case(range(1,5)) seems like it should
+        # include 1, 2, 3, 4, 5.
+        # But list(range(1,5)) is [1,2,3,4]. So that would be inconsistent.
+        # Thoughts?
+        # I'm going with 1,2,3,4,5 for range(1,5) for now.
+        with switch(value) as s:
+            s.case(range(1, 5), lambda: get_set_case("1-to-5"))
+            s.case(range(6, 7), lambda: get_set_case("6-to-7"))
+            s.default(lambda: get_set_case('default'))
+
+        self.assertEqual(executed_case, "6-to-7")
+
+    def test_multiple_values_one_case_list(self):
+        value = 6
+
+        executed_case = None
+
+        def get_set_case(val):
+            nonlocal executed_case
+            executed_case = val
+
+        with switch(value) as s:
+            s.case([1, 3, 5, 7], lambda: get_set_case("odd"))
+            s.case([0, 2, 4, 6, 8], lambda: get_set_case("even"))
+            s.default(lambda: get_set_case('default'))
+
+        self.assertEqual(executed_case, "even")