Translation cleanups

A number of cleanups and disentanglements to the current translator implementations:

• Extract a real abstract Translator interface
• Remove the mapping based approach from the FloatTranslator to make it actually accept floating point values unequal exact integers

saqc/core/translation/basescheme.py

@@ -34,11 +34,11 @@ class TranslationScheme:  # pragma: no cover
         pass
 
     @abstractmethod
-    def forward(self, flags: pd.DataFrame | DictOfSeries) -> Flags:
+    def toInternal(self, flags: pd.DataFrame | DictOfSeries) -> Flags:
         pass
 
     @abstractmethod
-    def backward(self, flags: Flags, attrs: dict | None = None) -> DictOfSeries:
+    def toExternal(self, flags: Flags, attrs: dict | None = None) -> DictOfSeries:
         pass
 
 
@@ -150,7 +150,7 @@ class MappingScheme(TranslationScheme):
             return float(flag)
         return float(self._forward[flag])
 
-    def forward(self, flags: pd.DataFrame | DictOfSeries | pd.Series) -> Flags:
+    def toInternal(self, flags: pd.DataFrame | DictOfSeries | pd.Series) -> Flags:
         """
         Translate from 'external flags' to 'internal flags'
 
@@ -165,7 +165,7 @@ class MappingScheme(TranslationScheme):
         """
         return Flags(self._translate(flags, self._forward))
 
-    def backward(
+    def toExternal(
         self,
         flags: Flags,
         attrs: dict | None = None,
@@ -206,7 +206,7 @@ class FloatScheme(TranslationScheme):
         except (TypeError, ValueError, OverflowError):
             raise ValueError(f"invalid flag, expected a numerical value, got: {flag}")
 
-    def forward(self, flags: pd.DataFrame | DictOfSeries) -> Flags:
+    def toInternal(self, flags: pd.DataFrame | DictOfSeries) -> Flags:
         try:
             return Flags(flags.astype(float))
         except (TypeError, ValueError, OverflowError):
@@ -214,7 +214,7 @@ class FloatScheme(TranslationScheme):
                 f"invalid flag(s), expected a collection of numerical values, got: {flags}"
             )
 
-    def backward(self, flags: Flags, attrs: dict | None = None) -> DictOfSeries:
+    def toExternal(self, flags: Flags, attrs: dict | None = None) -> DictOfSeries:
         out = flags.toDios()
         out.attrs = attrs or {}
         return out