Allow `__delitem__`-like tag deletion. (#49)

* Allow delitem-like tag deletion.

* Add `tags.keys()` as an alias for `tags.get()`.

* Allow `=` in `value`, simplify argument cleaning.

2 files changed, 27 insertions, 11 deletions

diff --git a/bot/__init__.py b/bot/__init__.py
index 40c4eefdc..c7d360408 100644
--- a/bot/__init__.py
+++ b/bot/__init__.py
@@ -201,17 +201,23 @@ def _get_word(self) -> str:
             key = clean_argument(self.buffer[self.index:equals_pos])
 
             # Value: The second argument, specified after the `=`
-            value = (
-                clean_argument(
-                    self.buffer.split("=")[1]
-                )
-                .replace("'", "\\'")  # escape any unescaped quotes
-            )
-            log.trace(f"Command mimicks setitem. Key: {key!r}, value: {value!r}.")
-
-            # Use the cog's `set` command.
-            result = self.buffer[self.previous:self.index] + ".set"
-            args = f'"{key}" "{value}"'
+            right_hand = self.buffer.split("=", maxsplit=1)[1].strip()
+
+            # If the value is None or '', mimick `bot.tags.delete(key)`
+            if right_hand in ("None", "''", '""'):
+                log.trace(f"Command mimicks delitem. Key: {key!r}.")
+                result = self.buffer[self.previous:self.index] + ".delete"
+                args = f'"{key}"'
+
+            # Otherwise, assume assignment, for example `bot.tags['this'] = 'that'`
+            else:
+                # Escape any unescaped quotes
+                value = clean_argument(right_hand).replace("'", "\\'")
+                log.trace(f"Command mimicks setitem. Key: {key!r}, value: {value!r}.")
+
+                # Use the cog's `set` command.
+                result = self.buffer[self.previous:self.index] + ".set"
+                args = f'"{key}" "{value}"'
 
         # Syntax is god knows what, pass it along
         # in the future, this should probably return / throw SyntaxError
diff --git a/bot/cogs/tags.py b/bot/cogs/tags.py
index 645835f53..b3569b782 100644
--- a/bot/cogs/tags.py
+++ b/bot/cogs/tags.py
@@ -349,6 +349,16 @@ class Tags:
 
         return await ctx.send(embed=embed)
 
+    @command(name="tags.keys()")
+    async def keys_command(self, ctx: Context):
+        """
+        Alias for `tags.get()` with no arguments.
+
+        :param ctx: discord message context
+        """
+
+        return await ctx.invoke(self.get_command)
+
 
 def setup(bot):
     bot.add_cog(Tags(bot))