feat: add conversion for fixed ABI types

src/ape/managers/converters.py

@@ -1,3 +1,4 @@
+import re
 from datetime import datetime, timedelta, timezone
 from decimal import Decimal
 from typing import Any, Dict, List, Sequence, Tuple, Type, Union
@@ -185,6 +186,22 @@ def convert(self, value: Union[str, datetime, timedelta]) -> int:
             raise ConversionError()
 
 
+class StringDecimalConverter(ConverterAPI):
+    """
+    Convert string-formatted floating point values to `Decimal` type.
+    """
+
+    def is_convertible(self, value: Any) -> bool:
+        # Matches only string-formatted floats with an optional sign character (+/-).
+        # Leading and trailing zeros are required.
+        # NOTE: `re.fullmatch` will only match the full string, so "1.0 ether" and "10.0 USDC"
+        # will not be identified as convertible.
+        return isinstance(value, str) and re.fullmatch(r"[+-]?\d+\.\d+", value) is not None
+
+    def convert(self, value: str) -> Decimal:
+        return Decimal(value)
+
+
 class ConversionManager(BaseManager):
     """
     A singleton that manages all the converters.
@@ -219,7 +236,7 @@ def _converters(self) -> Dict[Type, List[ConverterAPI]]:
                 StringIntConverter(),
                 AccountIntConverter(),
             ],
-            Decimal: [],
+            Decimal: [StringDecimalConverter()],
             bool: [],
             str: [],
         }

src/ape_ethereum/ecosystem.py

@@ -1,5 +1,6 @@
 import re
 from copy import deepcopy
+from decimal import Decimal
 from functools import cached_property
 from typing import Any, ClassVar, Dict, Iterator, List, Optional, Sequence, Tuple, Type, Union, cast
 
@@ -582,6 +583,9 @@ def _python_type_for_abi_type(self, abi_type: ABIType) -> Union[Type, Sequence]:
         elif "int" in abi_type.type:
             return int
 
+        elif "fixed" in abi_type.type:
+            return Decimal
+
         raise ConversionError(f"Unable to convert '{abi_type}'.")
 
     def encode_calldata(self, abi: Union[ConstructorABI, MethodABI], *args) -> HexBytes:

tests/functional/conversion/test_decimal.py

@@ -0,0 +1,83 @@
+from decimal import Decimal
+
+import pytest
+
+from ape.exceptions import ConversionError
+
+
+def test_convert_formatted_float_strings_to_decimal(convert):
+    test_strings = [
+        "1.000",
+        "1.00",
+        "1.0",
+        "0.1",
+        "0.01",
+        "0.001",
+    ]
+    for test_string in test_strings:
+        actual = convert(test_string, Decimal)
+        assert actual == Decimal(test_string)
+
+
+def test_convert_badly_formatted_float_strings_to_decimal(convert):
+    test_strings = [
+        ".1",
+        "1.",
+        ".",
+    ]
+    for test_string in test_strings:
+        with pytest.raises(
+            ConversionError, match=f"No conversion registered to handle '{test_string}'"
+        ):
+            convert(test_string, Decimal)
+
+
+def test_convert_int_strings(convert):
+    test_strings = [
+        "1",
+        "10",
+        "100",
+    ]
+    for test_string in test_strings:
+        with pytest.raises(
+            ConversionError, match=f"No conversion registered to handle '{test_string}'"
+        ):
+            convert(test_string, Decimal)
+
+
+def test_convert_alphanumeric_strings(convert):
+    test_strings = [
+        "a",
+        "H",
+        "XYZ",
+    ]
+    for test_string in test_strings:
+        with pytest.raises(
+            ConversionError, match=f"No conversion registered to handle '{test_string}'"
+        ):
+            convert(test_string, Decimal)
+
+
+def test_convert_strings_with_token_names(convert):
+    test_strings = [
+        "0.999 DAI",
+        "10.0 USDC",
+    ]
+    for test_string in test_strings:
+        with pytest.raises(
+            ConversionError, match=f"No conversion registered to handle '{test_string}'"
+        ):
+            convert(test_string, Decimal)
+
+
+def test_convert_strings_with_ether_alias(convert):
+    test_strings = [
+        "0 wei",
+        "999 gwei",
+        "1.0 ether",
+    ]
+    for test_string in test_strings:
+        with pytest.raises(
+            ConversionError, match=f"No conversion registered to handle '{test_string}'"
+        ):
+            convert(test_string, Decimal)