fix infer iterable signature and clean up TypeInferencer API

src/configmypy/type_inference.py

@@ -62,7 +62,7 @@ def infer_str(var, strict:bool=True):
     else:
         return str(var)
 
-def infer_iterable(var, inner_type: Callable=None, strict: bool=True):
+def infer_iterable(var, strict: bool=True, inner_type: Callable=None):
     # Use ast.literal_eval to parse the iterable tree,
     # then use custom type handling to infer the inner types
     raw_ast_iter = literal_eval(var)
@@ -109,25 +109,30 @@ def __init__(self, orig_type: Callable, strict: bool=True):
 
         """
         if orig_type == type(None):
-            self.orig_type = infer_str
+            self.orig_type = str
         else:
             self.orig_type = orig_type
         self.strict = strict
+
+        if self.orig_type == str or self.orig_type == type(None):
+            self.type_callable = infer_str
+        elif self.orig_type == bool or self.orig_type == ScalarBoolean:
+            self.type_callable = infer_boolean
+        elif self.orig_type == float or self.orig_type == int or self.orig_type == ScalarFloat or self.orig_type == ScalarInt:
+            self.type_callable = infer_numeric
+        elif self.orig_type == tuple or self.orig_type == list or self.orig_type == CommentedMap or self.orig_type == CommentedSeq:
+            self.type_callable = infer_iterable
+        else:
+            self.type_callable = self.orig_type
 
     def __call__(self, var):
         """
         Callable method passed to argparse's builtin Callable type argument.
         var: original variable (any type)
 
+        calls the proper type inferencer
         """
-        if self.orig_type == bool or self.orig_type == ScalarBoolean:
-            return infer_boolean(var, self.strict)
-        elif self.orig_type == float or self.orig_type == int or self.orig_type == ScalarFloat or self.orig_type == ScalarInt:
-            return infer_numeric(var, self.strict)
-        elif self.orig_type == tuple or self.orig_type == list or self.orig_type == CommentedMap or self.orig_type == CommentedSeq:
-            return infer_iterable(var, None, self.strict)
-        else:
-            if self.strict:
-                return infer_str(var)
-            else:
-                return self.orig_type(var)
+        return self.type_callable(var, self.strict)
+
+    def __repr__(self):
+        return f"TypeInferencer[{self.orig_type}]"