errors=r.SET_NULL/r.IGNORE options for parsedate/parsedatetime, closes #416

sqlite_utils/cli.py

@@ -2583,12 +2583,16 @@ def _generate_convert_help():
     """
     ).strip()
     recipe_names = [
-        n for n in dir(recipes) if not n.startswith("_") and n not in ("json", "parser")
+        n
+        for n in dir(recipes)
+        if not n.startswith("_")
+        and n not in ("json", "parser")
+        and callable(getattr(recipes, n))
     ]
     for name in recipe_names:
         fn = getattr(recipes, name)
-        help += "\n\nr.{}{}\n\n  {}".format(
-            name, str(inspect.signature(fn)), fn.__doc__
+        help += "\n\nr.{}{}\n\n\b{}".format(
+            name, str(inspect.signature(fn)), fn.__doc__.rstrip()
         )
     help += "\n\n"
     help += textwrap.dedent(

sqlite_utils/recipes.py

@@ -1,19 +1,56 @@
 from dateutil import parser
 import json
 
-
-def parsedate(value, dayfirst=False, yearfirst=False):
-    "Parse a date and convert it to ISO date format: yyyy-mm-dd"
-    return (
-        parser.parse(value, dayfirst=dayfirst, yearfirst=yearfirst).date().isoformat()
-    )
+IGNORE = object()
+SET_NULL = object()
 
 
-def parsedatetime(value, dayfirst=False, yearfirst=False):
-    "Parse a datetime and convert it to ISO datetime format: yyyy-mm-ddTHH:MM:SS"
-    return parser.parse(value, dayfirst=dayfirst, yearfirst=yearfirst).isoformat()
+def parsedate(value, dayfirst=False, yearfirst=False, errors=None):
+    """
+    Parse a date and convert it to ISO date format: yyyy-mm-dd
+    \b
+    - dayfirst=True: treat xx as the day in xx/yy/zz
+    - yearfirst=True: treat xx as the year in xx/yy/zz
+    - errors=r.IGNORE to ignore values that cannot be parsed
+    - errors=r.SET_NULL to set values that cannot be parsed to null
+    """
+    try:
+        return (
+            parser.parse(value, dayfirst=dayfirst, yearfirst=yearfirst)
+            .date()
+            .isoformat()
+        )
+    except parser.ParserError:
+        if errors is IGNORE:
+            return value
+        elif errors is SET_NULL:
+            return None
+        else:
+            raise
+
+
+def parsedatetime(value, dayfirst=False, yearfirst=False, errors=None):
+    """
+    Parse a datetime and convert it to ISO datetime format: yyyy-mm-ddTHH:MM:SS
+    \b
+    - dayfirst=True: treat xx as the day in xx/yy/zz
+    - yearfirst=True: treat xx as the year in xx/yy/zz
+    - errors=r.IGNORE to ignore values that cannot be parsed
+    - errors=r.SET_NULL to set values that cannot be parsed to null
+    """
+    try:
+        return parser.parse(value, dayfirst=dayfirst, yearfirst=yearfirst).isoformat()
+    except parser.ParserError:
+        if errors is IGNORE:
+            return value
+        elif errors is SET_NULL:
+            return None
+        else:
+            raise
 
 
 def jsonsplit(value, delimiter=",", type=str):
-    'Convert a string like a,b,c into a JSON array ["a", "b", "c"]'
+    """
+    Convert a string like a,b,c into a JSON array ["a", "b", "c"]
+    """
     return json.dumps([type(s.strip()) for s in value.split(delimiter)])