Add get and find helpers (#103)

disagreement/__init__.py

@@ -51,7 +51,15 @@ from .errors import (
     NotFound,
 )
 from .color import Color
-from .utils import escape_markdown, escape_mentions, message_pager, utcnow, snowflake_time
+from .utils import (
+    utcnow,
+    message_pager,
+    get,
+    find,
+    escape_markdown,
+    escape_mentions,
+    snowflake_time,
+)
 from .enums import (
     GatewayIntent,
     GatewayOpcode,
@@ -153,6 +161,8 @@ __all__ = [
     "escape_markdown",
     "escape_mentions",
     "message_pager",
+    "get",
+    "find",
     "snowflake_time",
     "GatewayIntent",
     "GatewayOpcode",

disagreement/utils.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from datetime import datetime, timezone
-from typing import Any, AsyncIterator, Dict, Optional, TYPE_CHECKING
+from typing import Any, AsyncIterator, Dict, Iterable, Optional, TYPE_CHECKING, Callable
 import re
 
 # Discord epoch in milliseconds (2015-01-01T00:00:00Z)
@@ -18,20 +18,23 @@ def utcnow() -> datetime:
     return datetime.now(timezone.utc)
 
 
+def find(predicate: Callable[[Any], bool], iterable: Iterable[Any]) -> Optional[Any]:
+    """Return the first element in ``iterable`` matching the ``predicate``."""
+    for element in iterable:
+        if predicate(element):
+            return element
+    return None
+
+
+def get(iterable: Iterable[Any], **attrs: Any) -> Optional[Any]:
+    """Return the first element with matching attributes."""
+    def predicate(elem: Any) -> bool:
+        return all(getattr(elem, attr, None) == value for attr, value in attrs.items())
+    return find(predicate, iterable)
+
+
 def snowflake_time(snowflake: int) -> datetime:
-    """Return the creation time of a Discord snowflake.
-
-    Parameters
-    ----------
-    snowflake:
-        The snowflake ID to convert.
-
-    Returns
-    -------
-    datetime
-        The UTC timestamp embedded in the snowflake.
-    """
-
+    """Return the creation time of a Discord snowflake."""
     timestamp_ms = (snowflake >> 22) + DISCORD_EPOCH
     return datetime.fromtimestamp(timestamp_ms / 1000, tz=timezone.utc)
 
@@ -43,32 +46,11 @@ async def message_pager(
     before: Optional[str] = None,
     after: Optional[str] = None,
 ) -> AsyncIterator["Message"]:
-    """Asynchronously paginate a channel's messages.
-
-    Parameters
-    ----------
-    channel:
-        The :class:`TextChannel` to fetch messages from.
-    limit:
-        The maximum number of messages to yield. ``None`` fetches until no
-        more messages are returned.
-    before:
-        Fetch messages with IDs less than this snowflake.
-    after:
-        Fetch messages with IDs greater than this snowflake.
-
-    Yields
-    ------
-    Message
-        Messages in the channel, oldest first.
-    """
-
+    """Asynchronously paginate a channel's messages."""
     remaining = limit
     last_id = before
     while remaining is None or remaining > 0:
-        fetch_limit = 100
-        if remaining is not None:
-            fetch_limit = min(fetch_limit, remaining)
+        fetch_limit = min(100, remaining) if remaining is not None else 100
 
         params: Dict[str, Any] = {"limit": fetch_limit}
         if last_id is not None:
@@ -135,36 +117,10 @@ class Paginator:
 
 
 def escape_markdown(text: str) -> str:
-    """Escape Discord markdown formatting in ``text``.
-
-    Parameters
-    ----------
-    text:
-        The text to escape.
-
-    Returns
-    -------
-    str
-        The escaped text with Discord formatting characters preceded by a
-        backslash.
-    """
-
+    """Escape Discord markdown formatting in ``text``."""
     return re.sub(r"([\\*_~`>|])", r"\\\1", text)
 
 
 def escape_mentions(text: str) -> str:
-    """Escape Discord mentions in ``text``.
-
-    Parameters
-    ----------
-    text:
-        The text in which to escape mentions.
-
-    Returns
-    -------
-    str
-        The text with ``@`` characters replaced by ``@\u200b`` to prevent
-        unintended mentions.
-    """
-
+    """Escape Discord mentions in ``text``."""
     return text.replace("@", "@\u200b")

tests/test_utils.py

@@ -1,10 +1,13 @@
 from datetime import datetime, timezone
+from types import SimpleNamespace
 
 from disagreement.utils import (
     escape_markdown,
     escape_mentions,
     utcnow,
-    snowflake_time
+    snowflake_time,
+    find,
+    get
 )
 
 
@@ -13,6 +16,22 @@ def test_utcnow_timezone():
     assert now.tzinfo == timezone.utc
 
 
+def test_find_returns_matching_element():
+    seq = [1, 2, 3]
+    assert find(lambda x: x > 1, seq) == 2
+    assert find(lambda x: x > 3, seq) is None
+
+
+def test_get_matches_attributes():
+    items = [
+        SimpleNamespace(id=1, name="a"),
+        SimpleNamespace(id=2, name="b"),
+    ]
+    assert get(items, id=2) is items[1]
+    assert get(items, id=1, name="a") is items[0]
+    assert get(items, name="c") is None
+
+
 def test_snowflake_time():
     dt = datetime(2020, 1, 1, tzinfo=timezone.utc)
     ms = int(dt.timestamp() * 1000) - 1420070400000