[feat]: support conversion from YDS back to French

Signed-off-by: GitHub <noreply@github.com>

README.md

@@ -21,17 +21,19 @@ pip install pyclimb
 import pyclimb
 
 
-pyclimb.convert(grade='6a+', to='YDS')
+pyclimb.convert(grade='6a+', grade_system='French', to='YDS')
 // '5.10b'
-pyclimb.convert(grade='9c', to='YDS')
+pyclimb.convert(grade='9c', grade_system='French', to='YDS')
 // '5.15d'
+pyclimb.convert(grade='5.12a', grade_system='YDS', to='French')
+// '7a+'
 ```
 
 ## Note
 
 This is a package under active development. Currently, only the following conversions are being supported:
 
-- [sport climbing] conversion from the French grading system to the YDS ([Yosemite Decimal System](https://en.wikipedia.org/wiki/Yosemite_Decimal_System)).
+- [sport climbing] conversion between French grading system and the YDS ([Yosemite Decimal System](https://en.wikipedia.org/wiki/Yosemite_Decimal_System)).
 
 Other conversions and different types of climbing will be included soon. These changes may drastically change the user-facing API, so do consult the semantic versioning of this package before upgrading to a newer version.
 

pyclimb/__init__.py

@@ -1,3 +1,3 @@
 from .converter import convert
 
-__version__ = "0.1.0"
+__version__ = "0.2.0"

pyclimb/converter.py

@@ -1,17 +1,19 @@
-from pyclimb import exceptions, mappers
-from pyclimb.grading_systems import GradingSystem
+from pyclimb import exceptions
+from pyclimb.grading_system import GradingSystem
+from pyclimb.mapper import get_conversion, mapper
 
 
-def convert(grade: str, to: str) -> str:
+def convert(grade: str, grade_system: str, to: str) -> str:
     """Converts a climbing grade to a specified grading system.
 
     Example:
-        >>> pyclimb.convert(grade='6a+', to='YDS')
-        >>> pyclimb.convert(grade='5.12a', to='French')
+        >>> pyclimb.convert(grade='6a+', grade_system='French', to='YDS')
+        >>> pyclimb.convert(grade='5.12a', grade_system='YDS', to='French')
 
     Args:
         grade: The grade to be converted.
-        to: The grading system onto which the grade will be converted.
+        grade_system: The grade system to which `grade` belongs.
+        to: The grading system onto which the `grade` will be converted.
 
     Returns:
         The converted grade.
@@ -20,17 +22,29 @@ def convert(grade: str, to: str) -> str:
         GradeConversionError: Error raised when the grade conversion fails.
     """
     try:
-        grad_system = GradingSystem(to)
+        input_grading = GradingSystem(grade_system)
 
     except ValueError:
         raise exceptions.GradeConversionError(
-            "Grade could not be converted: `to` is not a recognized grading system."
-        )
+            f"Grade could not be converted: {grade_system} is not a recognized grading system."
+        ) from None
 
     try:
-        return mappers.french2yds[grade]
+        output_grading = GradingSystem(to)
+
+    except ValueError:
+        raise exceptions.GradeConversionError(
+            f"Grade could not be converted: {to} is not a recognized grading system."
+        ) from None
+
+    conversion = get_conversion(
+        from_system=input_grading.value, to_system=output_grading.value
+    )
+
+    try:
+        return mapper[conversion][grade]
 
     except KeyError:
         raise exceptions.GradeConversionError(
-            "Grade could not be converted: `grade` not recognized."
-        )
+            f"Grade could not be converted: {grade} not recognized."
+        ) from None

pyclimb/grading_systems.py → pyclimb/grading_system.py

@@ -3,4 +3,5 @@
 
 class GradingSystem(enum.Enum):
 
+    french = "French"
     yds = "YDS"

pyclimb/mapper.py

@@ -0,0 +1,109 @@
+"""
+The grade conversion implementation.
+
+Each item of the mapper (dictionary) is a conversion path with:
+
+  - key following the naming convention "A2B" (`A` is the input grading, `B` is the output grading)
+  - value being the mapping from an `A` grade to a `B` grade.
+  
+Note that an "A2B" mapping is not bijective.
+"""
+
+mapper = {
+    "French2YDS": {
+        "1a": "N/A",
+        "1a+": "N/A",
+        "1b": "N/A",
+        "1b+": "N/A",
+        "1c": "5.0",
+        "1c+": "5.0",
+        "2a": "5.1",
+        "2a+": "5.1",
+        "2b": "5.1",
+        "2b+": "5.2",
+        "2c": "5.2",
+        "2c+": "5.3",
+        "3a": "5.3",
+        "3a+": "5.4",
+        "3b": "5.4",
+        "3b+": "5.4",
+        "3c": "5.5",
+        "3c+": "5.5",
+        "4a": "5.6",
+        "4a+": "5.6",
+        "4b": "5.6",
+        "4b+": "5.7",
+        "4c": "5.7",
+        "4c+": "5.8",
+        "5a": "5.8",
+        "5a+": "5.8",
+        "5b": "5.9",
+        "5b+": "5.9",
+        "5c": "5.10a",
+        "5c+": "5.10a",
+        "6a": "5.10a",
+        "6a+": "5.10b",
+        "6b": "5.10c",
+        "6b+": "5.10d",
+        "6c": "5.11b",
+        "6c+": "5.11c",
+        "7a": "5.11d",
+        "7a+": "5.12a",
+        "7b": "5.12b",
+        "7b+": "5.12c",
+        "7c": "5.12d",
+        "7c+": "5.13a",
+        "8a": "5.13b",
+        "8a+": "5.13c",
+        "8b": "5.13d",
+        "8b+": "5.14a",
+        "8c": "5.14b",
+        "8c+": "5.14c",
+        "9a": "5.14d",
+        "9a+": "5.15a",
+        "9b": "5.15b",
+        "9b+": "5.15c",
+        "9c": "5.15d",
+    },
+    "YDS2French": {
+        "5.0": "1c+",
+        "5.1": "2a+",
+        "5.2": "2b+",
+        "5.3": "3a",
+        "5.4": "3b",
+        "5.5": "3c+",
+        "5.6": "4a+",
+        "5.7": "4c",
+        "5.8": "5a",
+        "5.9": "5b+",
+        "5.10a": "5c+",
+        "5.10b": "6a+",
+        "5.10c": "6b",
+        "5.10d": "6b+",
+        "5.11a": "6c",
+        "5.11b": "6c+",
+        "5.11c": "6c+",
+        "5.11d": "7a",
+        "5.12a": "7a+",
+        "5.12b": "7b",
+        "5.12c": "7b+",
+        "5.12d": "7c",
+        "5.13a": "7c+",
+        "5.13b": "8a",
+        "5.13c": "8a+",
+        "5.13d": "8b",
+        "5.14a": "8b+",
+        "5.14b": "8c",
+        "5.14c": "8c+",
+        "5.14d": "9a",
+        "5.15a": "9a+",
+        "5.15b": "9b",
+        "5.15c": "9b+",
+        "5.15d": "9c",
+    },
+}
+
+
+def get_conversion(from_system: str, to_system: str) -> str:
+    """Heuristic method to obtain conversion path."""
+    return f"{from_system}2{to_system}"

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pyclimb"
-version = "0.1.0"
+version = "0.2.0"
 description = "A library to easily convert climbing route grades between different grading systems."
 authors = ["ilias-ant <ilias.antonopoulos@yahoo.gr>"]
 readme = "README.md"

tests/test_converter.py

@@ -4,6 +4,29 @@
 
 
 class TestConverter:
+    def test_convert_with_unrecognized_output_grading_system(self):
+
+        with pytest.raises(pyclimb.exceptions.GradeConversionError) as exc:
+            pyclimb.convert("6a+", grade_system="French", to="bar")
+
+        assert "bar is not a recognized grading system" in str(exc.value)
+
+    def test_convert_with_unrecognized_input_grading_system(self):
+
+        with pytest.raises(pyclimb.exceptions.GradeConversionError) as exc:
+            pyclimb.convert("6a+", grade_system="foo", to="YDS")
+
+        assert "foo is not a recognized grading system" in str(exc.value)
+
+    def test_convert_with_unrecognized_grade(self):
+
+        with pytest.raises(pyclimb.exceptions.GradeConversionError) as exc:
+            pyclimb.convert(grade="foo", grade_system="French", to="YDS")
+
+        assert "foo not recognized" in str(exc.value)
+
+
+class TestConverterFrenchToYDS:
 
     french2yds_map = [
         ("1a", "N/A"),
@@ -61,21 +84,58 @@ class TestConverter:
         ("9c", "5.15d"),
     ]
 
-    def test_convert_with_unrecognized_grading_system(self):
+    @pytest.mark.parametrize("grade, converted_grade", french2yds_map)
+    def test_convert_french_to_yds(self, grade, converted_grade):
 
-        with pytest.raises(pyclimb.exceptions.GradeConversionError) as exc:
-            pyclimb.convert("6a+", to="foo")
+        assert (
+            pyclimb.convert(grade=grade, grade_system="French", to="YDS")
+            == converted_grade
+        )
 
-        assert "`to` is not a recognized grading system" in str(exc.value)
 
-    def test_convert_with_unrecognized_grade(self):
+class TestConverterYDSToFrench:
 
-        with pytest.raises(pyclimb.exceptions.GradeConversionError) as exc:
-            pyclimb.convert(grade="foo bar", to="YDS")
-
-        assert "`grade` not recognized" in str(exc.value)
+    yds2french_map = [
+        ("5.0", "1c+"),
+        ("5.1", "2a+"),
+        ("5.2", "2b+"),
+        ("5.3", "3a"),
+        ("5.4", "3b"),
+        ("5.5", "3c+"),
+        ("5.6", "4a+"),
+        ("5.7", "4c"),
+        ("5.8", "5a"),
+        ("5.9", "5b+"),
+        ("5.10a", "5c+"),
+        ("5.10b", "6a+"),
+        ("5.10c", "6b"),
+        ("5.10d", "6b+"),
+        ("5.11a", "6c"),
+        ("5.11b", "6c+"),
+        ("5.11c", "6c+"),
+        ("5.11d", "7a"),
+        ("5.12a", "7a+"),
+        ("5.12b", "7b"),
+        ("5.12c", "7b+"),
+        ("5.12d", "7c"),
+        ("5.13a", "7c+"),
+        ("5.13b", "8a"),
+        ("5.13c", "8a+"),
+        ("5.13d", "8b"),
+        ("5.14a", "8b+"),
+        ("5.14b", "8c"),
+        ("5.14c", "8c+"),
+        ("5.14d", "9a"),
+        ("5.15a", "9a+"),
+        ("5.15b", "9b"),
+        ("5.15c", "9b+"),
+        ("5.15d", "9c"),
+    ]
 
-    @pytest.mark.parametrize("grade, converted_grade", french2yds_map)
-    def test_convert_french_to_yds(self, grade, converted_grade):
+    @pytest.mark.parametrize("grade, converted_grade", yds2french_map)
+    def test_convert_yds_to_french(self, grade, converted_grade):
 
-        assert pyclimb.convert(grade=grade, to="YDS") == converted_grade
+        assert (
+            pyclimb.convert(grade=grade, grade_system="YDS", to="French")
+            == converted_grade
+        )