Optional second default argument to functions, closes #5

simonw · Mar 1, 2022 · 8356683 · 8356683
1 parent 090d9db
commit 8356683
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Showing 3 changed files with 50 additions and 8 deletions.
diff --git a/README.md b/README.md
@@ -44,6 +44,16 @@ select
 
 [Try that query](https://latest-with-plugins.datasette.io/fixtures?sql=select%0D%0A++dateutil_parse%28%2210+october+2020+3pm%22%29%2C%0D%0A++dateutil_parse_fuzzy%28%22This+is+due+10+september%22%29%2C%0D%0A++dateutil_parse%28%221%2F2%2F2020%22%29%2C%0D%0A++dateutil_parse%28%222020-03-04%22%29%2C%0D%0A++dateutil_parse_dayfirst%28%222020-03-04%22%29%3B)
 
+### Optional default dates
+
+The `dateutil_parse()`, `dateutil_parse_fuzzy()`, `dateutil_parse_dayfirst()` and `dateutil_parse_fuzzy_dayfirst()` functions all accept an optional second argument specifying a "default" datetime to consider if some of the details are missing. For example, the following:
+```sql
+select dateutil_parse('1st october', '1985-01-01')
+```
+Will return `1985-10-01T00:00:00` - the missing year is replaced with the year from the default date.
+
+[Example query demonstrating the default date argument](https://latest-with-plugins.datasette.io/fixtures?sql=with+times+as+%28%0D%0A++select%0D%0A++++datetime%28%27now%27%29+as+t%0D%0A++union%0D%0A++select%0D%0A++++datetime%28%27now%27%2C+%27-1+year%27%29%0D%0A++union%0D%0A++select%0D%0A++++datetime%28%27now%27%2C+%27-3+years%27%29%0D%0A%29%0D%0Aselect+t%2C+dateutil_parse_fuzzy%28%22This+is+due+10+september%22%2C+t%29+from+times)
+
 ### Calculating Easter
 
 - `dateutil_easter(year)` - returns the date for Easter in that year, for example `dateutil_easter("2020")` returns `2020-04-12`.

diff --git a/datasette_dateutil/__init__.py b/datasette_dateutil/__init__.py
@@ -11,6 +11,9 @@
 
 
 def _dateutil_parse_shared(s, **kwargs):
+    default = kwargs.get("default")
+    if default is not None:
+        kwargs["default"] = parse(kwargs["default"])
     if not kwargs.get("dayfirst"):
         kwargs["dayfirst"] = False
     if not s:
@@ -21,20 +24,20 @@ def _dateutil_parse_shared(s, **kwargs):
         return None
 
 
-def dateutil_parse(s):
-    return _dateutil_parse_shared(s)
+def dateutil_parse(s, default=None):
+    return _dateutil_parse_shared(s, default=default)
 
 
-def dateutil_parse_fuzzy(s):
-    return _dateutil_parse_shared(s, fuzzy=True)
+def dateutil_parse_fuzzy(s, default=None):
+    return _dateutil_parse_shared(s, fuzzy=True, default=default)
 
 
-def dateutil_parse_dayfirst(s):
-    return _dateutil_parse_shared(s, dayfirst=True)
+def dateutil_parse_dayfirst(s, default=None):
+    return _dateutil_parse_shared(s, dayfirst=True, default=default)
 
 
-def dateutil_parse_fuzzy_dayfirst(s):
-    return _dateutil_parse_shared(s, fuzzy=True, dayfirst=True)
+def dateutil_parse_fuzzy_dayfirst(s, default=None):
+    return _dateutil_parse_shared(s, fuzzy=True, dayfirst=True, default=default)
 
 
 def dateutil_easter(year):
@@ -102,6 +105,13 @@ def prepare_connection(conn):
     conn.create_function(
         "dateutil_parse_fuzzy_dayfirst", 1, dateutil_parse_fuzzy_dayfirst
     )
+    # The two argument version of these (default date is second argument)
+    conn.create_function("dateutil_parse", 2, dateutil_parse)
+    conn.create_function("dateutil_parse_fuzzy", 2, dateutil_parse_fuzzy)
+    conn.create_function("dateutil_parse_dayfirst", 2, dateutil_parse_dayfirst)
+    conn.create_function(
+        "dateutil_parse_fuzzy_dayfirst", 2, dateutil_parse_fuzzy_dayfirst
+    )
     conn.create_function("dateutil_easter", 1, dateutil_easter)
     conn.create_function("dateutil_rrule", 1, dateutil_rrule)
     conn.create_function("dateutil_rrule", 2, dateutil_rrule)

diff --git a/tests/test_dateutil.py b/tests/test_dateutil.py
@@ -17,6 +17,7 @@ async def test_plugin_is_installed():
 @pytest.mark.parametrize(
     "sql,expected",
     [
+        # dateutil_parse variants with one argument
         ("select dateutil_parse('1st october 2009')", "2009-10-01T00:00:00"),
         ("select dateutil_parse('invalid')", None),
         ("select dateutil_parse('due on 1st october 2009')", None),
@@ -32,8 +33,28 @@ async def test_plugin_is_installed():
             "select dateutil_parse_fuzzy_dayfirst('due on 1/2/2003')",
             "2003-02-01T00:00:00",
         ),
+        # dateutil_parse variants with the optional second default datetime argument
+        (
+            "select dateutil_parse('1st october 2009', '10th september 2020')",
+            "2009-10-01T00:00:00",
+        ),
+        (
+            "select dateutil_parse('1st october', '10th september 2020')",
+            "2020-10-01T00:00:00",
+        ),
+        (
+            "select dateutil_parse_fuzzy('due on 1st october', '2020-01-01')",
+            "2020-10-01T00:00:00",
+        ),
+        ("select dateutil_parse_dayfirst('1/2', '1981-01-01')", "1981-02-01T00:00:00"),
+        (
+            "select dateutil_parse_fuzzy_dayfirst('due on 1/2', '1765-01-01')",
+            "1765-02-01T00:00:00",
+        ),
+        # dateutil_easter
         ("select dateutil_easter(2020)", "2020-04-12"),
         ("select dateutil_easter('invalid')", None),
+        # dateutil_rrule
         (
             "select dateutil_rrule('DTSTART:20200101\nFREQ=DAILY;INTERVAL=10;COUNT=5')",
             '["2020-01-01T00:00:00", "2020-01-11T00:00:00", "2020-01-21T00:00:00", "2020-01-31T00:00:00", "2020-02-10T00:00:00"]',
@@ -50,6 +71,7 @@ async def test_plugin_is_installed():
             "select dateutil_rrule_date('FREQ=DAILY;INTERVAL=10;COUNT=5', '2020-01-01')",
             '["2020-01-01", "2020-01-11", "2020-01-21", "2020-01-31", "2020-02-10"]',
         ),
+        # dateutil_dates_between
         (
             "select dateutil_dates_between('1 january 2020', '5 jan 2020', 0)",
             '["2020-01-01", "2020-01-02", "2020-01-03", "2020-01-04"]',