Add a bad time parser

Author: rec

nmr/types/time/constants.py

@@ -1,3 +1,4 @@
+from collections import Counter
 from enum import IntEnum, auto
 
 MICROSECOND_TO_YOCTOSECOND: int = 10 ** (24 - 6)
@@ -81,5 +82,3 @@ class Interval(IntEnum):
         Interval.YOCTOSECOND: 10 ** (24 - 24),
     },
 }
-
-assert set(i for s in SCALES.values() for i in s.values()) == set(Interval)

nmr/types/time/formats.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import itertools
+from datetime import datetime
+from functools import partial
+from typing import Callable, Iterable, Sequence
+
+from .constants import Interval
+from .time import Time
+
+
+def from_string(s: str) -> Time:
+    def parse(p: str) -> datetime | None:
+        try:
+            return datetime.strptime(s, p)
+        except ValueError:
+            return None
+
+    all_parsers = ((i, p) for i, parsers in PARSERS.items() for p in parsers)
+    times = [Time(i, dt) for i, p in all_parsers if (dt := parse(p))]
+    if not times:
+        raise ValueError("No format matched")
+    if len(times) > 1:
+        raise ValueError(f"Multiple formats matched {times=}")
+    return times[0]
+
+
+def to_string(t: Time) -> str:
+    return t.time.strftime(PARSERS[t.interval][0])
+
+
+def _product(*patterns: str, sep: str = " /") -> Iterable[str]:
+    yield from ("%" + f"{sep}%".join(c) for s, c in itertools.product(sep, *patterns))
+
+
+PARSERS: dict[Interval, Sequence[str]] = {
+    Interval.SECOND: ["%H:%M:%S", "%I:%M:%S%p"],
+    Interval.MINUTE: ["%H:%M", "%Hh%M", "%I:%M%p"],
+    Interval.HOUR: ["%Hh", "%I%p"],
+    Interval.DAY: [
+        *_product("d", "bBm", "Yy"),
+        *_product("Yy", "bBm", "d"),
+        *_product("d", "bBm"),
+        *_product("bBm", "d"),
+    ],
+    # Interval.WEEK: ["%m/%y"],
+    Interval.MONTH: [
+        *_product("bBm", "Yy"),
+        *_product("Yy", "bBm"),
+        *_product("bBm"),
+        *_product("d"),
+    ],
+    Interval.YEAR: [*_product("Yy")],
+    # Interval.DECADE: [_decade],
+    # Interval.CENTURY: [_century],
+}