Standardized __str__ format and id format

fin_defs/__init__.py

@@ -1,6 +1,19 @@
 """# Finance Definitions.
 
 Python library defining base types for financial processing.
+
+Defines a base `Asset` type, and various subtypes, for universal representation
+of these assets.
+
+Defined hierarchy:
+
+* `Asset`
+  - `Currency`
+    + `FiatCurrency`
+    + `CryptoCurrency`
+  - `Stock`
+  - `Index`
+  - `Commodity`
 """
 
 import dataclasses
@@ -22,7 +35,16 @@ RE_CRYPTO_TICKER_FORMAT = r'^\S+$'
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True)
 class StockExchange:
-    """Unified Stock Exchange identifiers."""
+    """Unified Stock Exchange identifiers.
+
+    Fields:
+    - `name`: Human-readable name.
+    - `mic`: Official MIC identifier.
+    - `bloomberg_id`: Identifier for lookup on Bloomberg.
+    - `crunchbase_id`: Identifier for lookup on Crunchbase.
+    - `yahoo_id`: Identifier for lookup on Yahoo! Finance.
+    - `eod_id`: Identifier for lookup on EOD.
+    """
 
     name: str
     mic: str
@@ -42,6 +64,7 @@ class Asset:
     """
 
     def names(self) -> list[str]:
+        """Returns a list of human readable names for this `Asset`."""
         return COMMON_NAMES.get(self, [])
 
     def to_polygon_id(self) -> str:
@@ -85,13 +108,15 @@ class Asset:
     def to_string_id(self) -> str:
         """Formats the asset id using the fin_defs asset format."""
         if isinstance(self, Stock):
-            return f'stock:{self}'
+            return f'stock:{self.ticker}.{self.exchange.mic}'
         if isinstance(self, FiatCurrency):
-            return f'fiat:{self}'
+            return f'fiat:{self.iso_code}'
         if isinstance(self, CryptoCurrency):
-            return f'crypto:{self}'
+            return f'crypto:{self.ccxt_symbol}'
         if isinstance(self, Index):
-            return f'index:{self}'
+            return f'index:{self.ticker}'
+        if isinstance(self, Commodity):
+            return f'commodity:{self.alpha_vantage_id}'
 
         raise NotImplementedError('Unsupported asset type: ' + str(self))
 
@@ -122,6 +147,9 @@ class Asset:
         msg = f'Unsupported asset format: {asset_id}'
         raise NotImplementedError(msg)
 
+    def __str__(self):
+        return self.to_string_id()
+
 
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True)
@@ -139,9 +167,6 @@ class FiatCurrency(Currency):
             msg = f'iso_code was not in correct format: {self.iso_code}'
             raise ValueError(msg)
 
-    def __str__(self):
-        return self.iso_code
-
 
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, eq=True)
@@ -156,10 +181,6 @@ class CryptoCurrency(Currency):
             raise ValueError(msg)
         """
 
-    def __str__(self):
-        return self.ccxt_symbol
-
-
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, eq=True)
 class Stock(Asset):
@@ -172,9 +193,6 @@ class Stock(Asset):
             msg = f'ticker was not in correct format: {self.ticker}'
             raise ValueError(msg)
 
-    def __str__(self):
-        return f'{self.ticker}.{self.exchange.mic}'
-
     @staticmethod
     def from_polygon_id(polygon_id: str, stock_exchange: StockExchange) -> 'Stock':
         return Stock(polygon_id, stock_exchange)
@@ -190,9 +208,6 @@ class Index(Asset):
             msg = f'ticker was not in correct format: {self.ticker}'
             raise ValueError(msg)
 
-    def __str__(self):
-        return self.ticker
-
 
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, eq=True)
@@ -204,9 +219,6 @@ class Commodity(Asset):
             msg = f'alpha_vantage_id was not in correct format: {self.alpha_vantage_id}'
             raise ValueError(msg)
 
-    def __str__(self):
-        return self.alpha_vantage_id
-
 
 Commodity.CRUDE_OIL_WTI = Commodity('WTI')
 Commodity.CRUDE_OIL_BRENT = Commodity('BRENT')
@@ -227,7 +239,7 @@ BTC = CryptoCurrency('BTC', coingecko_id='bitcoin')
 MPC = CryptoCurrency('MPC', coingecko_id='partisia-blockchain')
 SPX = Index('SPX')
 NDX = Index('NDX')
-USDT = CryptoCurrency('USDT', 'tether')
+USDT = CryptoCurrency('USDT', coingecko_id='tether')
 
 COMMON_NAMES: dict[Asset, list[str]] = {
     FiatCurrency('USD'): ['U.S. Dollar'],
@@ -246,15 +258,15 @@ COMMON_NAMES: dict[Asset, list[str]] = {
     NDX: ['Nasdaq 100'],
     BTC: ['Bitcoin BTC'],
     MPC: ['Partisia Blockchain MPC Token'],
-    CryptoCurrency('ETH', 'ethereum'): ['Ethereum Ether'],
+    CryptoCurrency('ETH', coingecko_id='ethereum'): ['Ethereum Ether'],
-    CryptoCurrency('DOGE', 'dogecoin'): ['Dogecoin'],
+    CryptoCurrency('DOGE', coingecko_id='dogecoin'): ['Dogecoin'],
-    CryptoCurrency('SOL', 'solana'): ['Solana SOL'],
+    CryptoCurrency('SOL', coingecko_id='solana'): ['Solana SOL'],
-    CryptoCurrency('ADA', 'cardano'): ['Cardano ADA'],
+    CryptoCurrency('ADA', coingecko_id='cardano'): ['Cardano ADA'],
-    CryptoCurrency('BNB', 'bnb'): ['Binance BNB'],
+    CryptoCurrency('BNB', coingecko_id='bnb'): ['Binance BNB'],
-    CryptoCurrency('MATIC', 'polygon'): ['Polygon MATIC'],
+    CryptoCurrency('MATIC', coingecko_id='polygon'): ['Polygon MATIC'],
     # Stable-coins
-    CryptoCurrency('DAI', 'dai'): ['DAI'],
+    CryptoCurrency('DAI', coingecko_id='dai'): ['DAI'],
-    CryptoCurrency('USDC', 'usdc'): ['USD Coin'],
+    CryptoCurrency('USDC', coingecko_id='usdc'): ['USD Coin'],
     USDT: ['Tether USDT'],
 }
 
@@ -384,7 +396,12 @@ class AssetInformation:
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, eq=True, slots=True)
 class AssetAmount:
-    """Decimal with associated asset unit."""
+    """Decimal with associated asset unit.
+
+    Fields:
+    - `asset`: Asset unit of amount.
+    - `amount`: Amount of given asset.
+    """
 
     asset: Asset
     amount: Decimal
@@ -447,6 +464,7 @@ class ExchangeRateSample(Asset):
     """Single exchange rate sample with a timestamp and various stats."""
 
     timestamp: datetime.date | datetime.datetime
+    base_asset: Asset
     _average: Decimal | None = None
     last: Decimal | None = None
     open: Decimal | None = None

test/test_ids.py

@@ -0,0 +1,12 @@
+import pytest
+
+import fin_defs
+
+@pytest.mark.parametrize('asset', fin_defs.WELL_KNOWN_SYMBOLS.values())
+def test_to_from_string_id(asset: fin_defs.Asset):
+    assert fin_defs.Asset.from_string_id(asset.to_string_id()) == asset
+import fin_defs
+
+@pytest.mark.parametrize('asset', fin_defs.WELL_KNOWN_SYMBOLS.values())
+def test_to_from_polygon_id(asset: fin_defs.Asset):
+    assert fin_defs.Asset.from_polygon_id(asset.to_polygon_id()) == asset