Handle scientific notation in to_number()

Instead just try to parse the number as an int, and
if that fails try float() before returning None.

Fixes #120.

Author: jamesls

jmespath/functions.py

@@ -202,12 +202,12 @@ def _func_to_number(self, arg):
             return arg
         else:
             try:
-                if '.' in arg:
-                    return float(arg)
-                else:
-                    return int(arg)
+                return int(arg)
             except ValueError:
-                return None
+                try:
+                    return float(arg)
+                except ValueError:
+                    return None
 
     @signature({'types': ['array', 'string']}, {'types': []})
     def _func_contains(self, subject, search):

tests/compliance/functions.json

@@ -495,6 +495,10 @@
       "expression": "to_number('1.0')",
       "result": 1.0
     },
+    {
+      "expression": "to_number('1e21')",
+      "result": 1e21
+    },
     {
       "expression": "to_number('1.1')",
       "result": 1.1