Cleanup dataclasses based metadata handling (closes #126)

climix/metadata.py

@@ -17,7 +17,6 @@ import xdg.BaseDirectory
 import yaml
 
 from .index import Index
-from .index_functions import SUPPORTED_OPERATORS, SUPPORTED_REDUCERS
 from .period import PeriodSpecification
 
 
@@ -86,6 +85,9 @@ class Parameter:
     kind: ParameterKind
 
 
+PARAMETER_KINDS = {}
+
+
 @dataclass
 class ParameterQuantity(Parameter):
     long_name: str
@@ -113,6 +115,9 @@ class ParameterQuantity(Parameter):
             self.units)
 
 
+PARAMETER_KINDS['quantity'] = ParameterQuantity
+
+
 @dataclass
 class ParameterOperator(Parameter):
     operator: str
@@ -127,6 +132,9 @@ class ParameterOperator(Parameter):
             self.operator)
 
 
+PARAMETER_KINDS['operator'] = ParameterOperator
+
+
 @dataclass
 class ParameterReducer(Parameter):
     reducer: str
@@ -141,6 +149,9 @@ class ParameterReducer(Parameter):
             self.reducer)
 
 
+PARAMETER_KINDS['reducer'] = ParameterReducer
+
+
 @dataclass
 class IndexFunction:
     name: str
@@ -172,21 +183,7 @@ class IndexDefinition:
 
 
 def build_parameter(metadata):
-    if metadata['kind'] == 'quantity':
-        param = ParameterQuantity(ParameterKind.QUANTITY,
-                                  metadata['long_name'],
-                                  metadata['standard_name'],
-                                  metadata['data'],
-                                  metadata['units'])
-    elif metadata['kind'] == 'operator':
-        param = ParameterOperator(ParameterKind.OPERATOR,
-                                  metadata['operator'])
-    elif metadata['kind'] == 'reducer':
-        param = ParameterReducer(ParameterKind.REDUCER,
-                                 metadata['reducer'])
-    else:
-        raise RuntimeError(f'Unknown parameter kind {metadata}')
-    return param
+    return PARAMETER_KINDS[metadata['kind']](**metadata)
 
 
 def build_index(metadata):