LiteralInt and LiteratInt_test (#40)

Author: nedtwigg

python/selfie-lib/selfie_lib/Literals.py

@@ -2,6 +2,7 @@
 from typing import Protocol, TypeVar
 from abc import abstractmethod
 from .EscapeLeadingWhitespace import EscapeLeadingWhitespace
+import io
 
 T = TypeVar("T")
 
@@ -41,6 +42,35 @@ def parse(self, string: str, language: Language) -> T:
 PADDING_SIZE = len(str(MAX_RAW_NUMBER)) - 1
 
 
+class LiteralInt(LiteralFormat[int]):
+    def _encode_underscores(
+        self, buffer: io.StringIO, value: int, language: Language
+    ) -> io.StringIO:
+        if value >= MAX_RAW_NUMBER:
+            mod = value % MAX_RAW_NUMBER
+            left_padding = PADDING_SIZE - len(str(mod))
+            self._encode_underscores(buffer, value // MAX_RAW_NUMBER, language)
+            buffer.write("_")
+            buffer.write("0" * left_padding)
+            buffer.write(str(mod))
+            return buffer
+        elif value < 0:
+            buffer.write("-")
+            self._encode_underscores(buffer, abs(value), language)
+            return buffer
+        else:
+            buffer.write(str(value))
+            return buffer
+
+    def encode(
+        self, value: int, language: Language, encoding_policy: EscapeLeadingWhitespace
+    ) -> str:
+        return self._encode_underscores(io.StringIO(), value, language).getvalue()
+
+    def parse(self, string: str, language: Language) -> int:
+        return int(string.replace("_", ""))
+
+
 class LiteralBoolean(LiteralFormat[bool]):
     def encode(
         self, value: bool, language: Language, encoding_policy: EscapeLeadingWhitespace

python/selfie-lib/tests/LiteralInt_test.py

@@ -0,0 +1,52 @@
+from selfie_lib.Literals import LiteralInt, Language
+from selfie_lib.EscapeLeadingWhitespace import EscapeLeadingWhitespace
+
+
+def _encode(value: int, expected: str):
+    literal_int = LiteralInt()
+    actual = literal_int.encode(value, Language.PYTHON, EscapeLeadingWhitespace.NEVER)
+    assert actual == expected, f"Expected '{expected}', but got '{actual}'"
+
+
+def _decode(value: str, expected: int):
+    literal_int = LiteralInt()
+    actual = literal_int.parse(value, Language.PYTHON)
+    assert actual == expected, f"Expected '{expected}', but got '{actual}'"
+
+
+class TestLiteralInt:
+    def test_encode(self):
+        test_cases = [
+            (0, "0"),
+            (1, "1"),
+            (-1, "-1"),
+            (999, "999"),
+            (-999, "-999"),
+            (1_000, "1_000"),
+            (-1_000, "-1_000"),
+            (1_000_000, "1_000_000"),
+            (-1_000_000, "-1_000_000"),
+            (2400500, "2_400_500"),
+            (2400501, "2_400_501"),
+            (200, "200"),
+            (1001, "1_001"),
+            (1010, "1_010"),
+            (10010, "10_010"),
+        ]
+        for value, expected in test_cases:
+            _encode(value, expected)
+
+    def test_decode(self):
+        test_cases = [
+            ("0", 0),
+            ("1", 1),
+            ("-1", -1),
+            ("999", 999),
+            ("9_99", 999),
+            ("9_9_9", 999),
+            ("-999", -999),
+            ("-9_99", -999),
+            ("-9_9_9", -999),
+        ]
+        for value, expected in test_cases:
+            _decode(value, expected)