move FunCall class from _ast to _functions module

This enables us to import _ast from _functions, without it being a
circular dependency.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/sdk/timeseries/formulas/_ast.py

@@ -17,7 +17,6 @@
 from ..._internal._math import is_close_to_zero
 from .._base_types import QuantityT, Sample
 from ._base_ast_node import AstNode, NodeSynchronizer
-from ._functions import Function
 
 _logger = logging.getLogger(__name__)
 
@@ -104,33 +103,6 @@ def _is_quantity_sample(
         return isinstance(sample.value, Quantity)
 
 
-@dataclass(kw_only=True)
-class FunCall(AstNode[QuantityT]):
-    """A function call in the formula."""
-
-    function: Function[QuantityT]
-
-    @override
-    async def evaluate(self) -> Sample[QuantityT] | QuantityT | None:
-        """Evaluate the function call with its arguments."""
-        return await self.function()
-
-    @override
-    def format(self, wrap: bool = False) -> str:
-        """Return a string representation of the function call node."""
-        return self.function.format()
-
-    @override
-    async def subscribe(self) -> None:
-        """Subscribe to any data streams needed by the function."""
-        await self.function.subscribe()
-
-    @override
-    async def unsubscribe(self) -> None:
-        """Unsubscribe from any data streams needed by the function."""
-        await self.function.unsubscribe()
-
-
 @dataclass(kw_only=True)
 class Constant(AstNode[QuantityT]):
     """A constant numerical value in the formula."""

src/frequenz/sdk/timeseries/formulas/_formula.py

@@ -22,7 +22,7 @@
 from . import _ast
 from ._base_ast_node import AstNode
 from ._formula_evaluator import FormulaEvaluatingActor
-from ._functions import Coalesce, Max, Min
+from ._functions import Coalesce, FunCall, Max, Min
 
 _logger = logging.getLogger(__name__)
 
@@ -299,7 +299,7 @@ def coalesce(
             else:
                 right_nodes.append(_ast.Constant(value=item))
 
-        new_root = _ast.FunCall(
+        new_root = FunCall(
             function=Coalesce([self.root] + right_nodes),
         )
 
@@ -332,7 +332,7 @@ def min(
             else:
                 right_nodes.append(_ast.Constant(value=item))
 
-        new_root = _ast.FunCall(
+        new_root = FunCall(
             function=Min([self.root] + right_nodes),
         )
 
@@ -365,7 +365,7 @@ def max(
             else:
                 right_nodes.append(_ast.Constant(value=item))
 
-        new_root = _ast.FunCall(
+        new_root = FunCall(
             function=Max([self.root] + right_nodes),
         )
 

src/frequenz/sdk/timeseries/formulas/_functions.py

@@ -18,6 +18,33 @@
 from ._base_ast_node import AstNode, NodeSynchronizer
 
 
+@dataclass(kw_only=True)
+class FunCall(AstNode[QuantityT]):
+    """A function call in the formula."""
+
+    function: Function[QuantityT]
+
+    @override
+    async def evaluate(self) -> Sample[QuantityT] | QuantityT | None:
+        """Evaluate the function call with its arguments."""
+        return await self.function()
+
+    @override
+    def format(self, wrap: bool = False) -> str:
+        """Return a string representation of the function call node."""
+        return self.function.format()
+
+    @override
+    async def subscribe(self) -> None:
+        """Subscribe to any data streams needed by the function."""
+        await self.function.subscribe()
+
+    @override
+    async def unsubscribe(self) -> None:
+        """Unsubscribe from any data streams needed by the function."""
+        await self.function.unsubscribe()
+
+
 @dataclass
 class Function(abc.ABC, Generic[QuantityT]):
     """A function that can be called in a formula expression."""

src/frequenz/sdk/timeseries/formulas/_parser.py

@@ -19,7 +19,7 @@
 from . import _ast, _token
 from ._base_ast_node import AstNode
 from ._formula import Formula
-from ._functions import Function
+from ._functions import FunCall, Function
 from ._lexer import Lexer
 from ._peekable import Peekable
 from ._resampled_stream_fetcher import ResampledStreamFetcher
@@ -177,7 +177,7 @@ def _parse_function_call(self) -> AstNode[QuantityT] | None:
                 f"Expected ',' or ')' in function call at position {fn_name.span}"
             )
 
-        return _ast.FunCall(
+        return FunCall(
             span=fn_name.span,
             function=Function.from_string(fn_name.value, params),
         )