Document & test eval_expression (#1225)

Author: bonjourmauko

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+### 41.5.7 [#1225](https://github.com/openfisca/openfisca-core/pull/1225)
+
+#### Technical changes
+
+- Refactor & test `eval_expression`
+
 ###  41.5.6 [#1185](https://github.com/openfisca/openfisca-core/pull/1185)
 
 #### Technical changes

openfisca_core/commons/__init__.py

@@ -8,6 +8,7 @@
     * :func:`.average_rate`
     * :func:`.concat`
     * :func:`.empty_clone`
+    * :func:`.eval_expression`
     * :func:`.marginal_rate`
     * :func:`.stringify_array`
     * :func:`.switch`
@@ -50,18 +51,21 @@
 
 """
 
-# Official Public API
-
+from . import types
+from .dummy import Dummy
 from .formulas import apply_thresholds, concat, switch
-from .misc import empty_clone, stringify_array
+from .misc import empty_clone, eval_expression, stringify_array
 from .rates import average_rate, marginal_rate
 
-__all__ = ["apply_thresholds", "concat", "switch"]
-__all__ = ["empty_clone", "stringify_array", *__all__]
-__all__ = ["average_rate", "marginal_rate", *__all__]
-
-# Deprecated
-
-from .dummy import Dummy
-
-__all__ = ["Dummy", *__all__]
+__all__ = [
+    "Dummy",
+    "apply_thresholds",
+    "average_rate",
+    "concat",
+    "empty_clone",
+    "eval_expression",
+    "marginal_rate",
+    "stringify_array",
+    "switch",
+    "types",
+]

openfisca_core/commons/dummy.py

@@ -20,3 +20,6 @@ def __init__(self) -> None:
             "and will be removed in the future.",
         ]
         warnings.warn(" ".join(message), DeprecationWarning, stacklevel=2)
+
+
+__all__ = ["Dummy"]

openfisca_core/commons/formulas.py

@@ -1,16 +1,17 @@
+from __future__ import annotations
+
 from collections.abc import Mapping
-from typing import Union
 
 import numpy
 
-from openfisca_core import types as t
+from . import types as t
 
 
 def apply_thresholds(
-    input: t.Array[numpy.float64],
+    input: t.Array[numpy.float32],
     thresholds: t.ArrayLike[float],
     choices: t.ArrayLike[float],
-) -> t.Array[numpy.float64]:
+) -> t.Array[numpy.float32]:
     """Makes a choice based on an input and thresholds.
 
     From a list of ``choices``, this function selects one of these values
@@ -38,26 +39,29 @@ def apply_thresholds(
         array([10, 10, 15, 15, 20])
 
     """
-    condlist: list[Union[t.Array[numpy.bool_], bool]]
+
+    condlist: list[t.Array[numpy.bool_] | bool]
     condlist = [input <= threshold for threshold in thresholds]
 
     if len(condlist) == len(choices) - 1:
         # If a choice is provided for input > highest threshold, last condition
         # must be true to return it.
         condlist += [True]
 
-    assert len(condlist) == len(
-        choices
-    ), "'apply_thresholds' must be called with the same number of thresholds than choices, or one more choice."
+    msg = (
+        "'apply_thresholds' must be called with the same number of thresholds "
+        "than choices, or one more choice."
+    )
+    assert len(condlist) == len(choices), msg
 
     return numpy.select(condlist, choices)
 
 
 def concat(
-    this: Union[t.Array[numpy.str_], t.ArrayLike[str]],
-    that: Union[t.Array[numpy.str_], t.ArrayLike[str]],
+    this: t.Array[numpy.str_] | t.ArrayLike[str],
+    that: t.Array[numpy.str_] | t.ArrayLike[str],
 ) -> t.Array[numpy.str_]:
-    """Concatenates the values of two arrays.
+    """Concatenate the values of two arrays.
 
     Args:
         this: An array to concatenate.
@@ -84,10 +88,10 @@ def concat(
 
 
 def switch(
-    conditions: t.Array[numpy.float64],
+    conditions: t.Array[numpy.float32],
     value_by_condition: Mapping[float, float],
-) -> t.Array[numpy.float64]:
-    """Mimicks a switch statement.
+) -> t.Array[numpy.float32]:
+    """Mimick a switch statement.
 
     Given an array of conditions, returns an array of the same size,
     replacing each condition item with the matching given value.
@@ -117,3 +121,6 @@ def switch(
     condlist = [conditions == condition for condition in value_by_condition]
 
     return numpy.select(condlist, tuple(value_by_condition.values()))
+
+
+__all__ = ["apply_thresholds", "concat", "switch"]

openfisca_core/commons/misc.py

@@ -1,14 +1,13 @@
-from typing import Optional, TypeVar
+from __future__ import annotations
 
+import numexpr
 import numpy
 
 from openfisca_core import types as t
 
-T = TypeVar("T")
 
-
-def empty_clone(original: T) -> T:
-    """Creates an empty instance of the same class of the original object.
+def empty_clone(original: object) -> object:
+    """Create an empty instance of the same class of the original object.
 
     Args:
         original: An object to clone.
@@ -30,22 +29,20 @@ def empty_clone(original: T) -> T:
         True
 
     """
-    Dummy: object
-    new: T
 
     Dummy = type(
         "Dummy",
         (original.__class__,),
-        {"__init__": lambda self: None},
+        {"__init__": lambda _: None},
     )
 
     new = Dummy()
     new.__class__ = original.__class__
     return new
 
 
-def stringify_array(array: Optional[t.Array[numpy.generic]]) -> str:
-    """Generates a clean string representation of a numpy array.
+def stringify_array(array: None | t.Array[numpy.generic]) -> str:
+    """Generate a clean string representation of a numpy array.
 
     Args:
         array: An array.
@@ -76,3 +73,33 @@ def stringify_array(array: Optional[t.Array[numpy.generic]]) -> str:
         return "None"
 
     return f"[{', '.join(str(cell) for cell in array)}]"
+
+
+def eval_expression(
+    expression: str,
+) -> str | t.Array[numpy.bool_] | t.Array[numpy.int32] | t.Array[numpy.float32]:
+    """Evaluate a string expression to a numpy array.
+
+    Args:
+        expression(str): An expression to evaluate.
+
+    Returns:
+        :obj:`object`: The result of the evaluation.
+
+    Examples:
+        >>> eval_expression("1 + 2")
+        array(3, dtype=int32)
+
+        >>> eval_expression("salary")
+        'salary'
+
+    """
+
+    try:
+        return numexpr.evaluate(expression)
+
+    except (KeyError, TypeError):
+        return expression
+
+
+__all__ = ["empty_clone", "eval_expression", "stringify_array"]

openfisca_core/commons/rates.py

@@ -1,16 +1,16 @@
-from typing import Optional
-
-from openfisca_core.types import Array, ArrayLike
+from __future__ import annotations
 
 import numpy
 
+from . import types as t
+
 
 def average_rate(
-    target: Array[numpy.float64],
-    varying: ArrayLike[float],
-    trim: Optional[ArrayLike[float]] = None,
-) -> Array[numpy.float64]:
-    """Computes the average rate of a target net income.
+    target: t.Array[numpy.float32],
+    varying: t.ArrayLike[float],
+    trim: None | t.ArrayLike[float] = None,
+) -> t.Array[numpy.float32]:
+    """Compute the average rate of a target net income.
 
     Given a ``target`` net income, and according to the ``varying`` gross
     income. Optionally, a ``trim`` can be applied consisting of the lower and
@@ -40,8 +40,8 @@ def average_rate(
         array([ nan,  0. , -0.5])
 
     """
-    average_rate: Array[numpy.float64]
 
+    average_rate: t.Array[numpy.float32]
     average_rate = 1 - target / varying
 
     if trim is not None:
@@ -61,11 +61,11 @@ def average_rate(
 
 
 def marginal_rate(
-    target: Array[numpy.float64],
-    varying: Array[numpy.float64],
-    trim: Optional[ArrayLike[float]] = None,
-) -> Array[numpy.float64]:
-    """Computes the marginal rate of a target net income.
+    target: t.Array[numpy.float32],
+    varying: t.Array[numpy.float32],
+    trim: None | t.ArrayLike[float] = None,
+) -> t.Array[numpy.float32]:
+    """Compute the marginal rate of a target net income.
 
     Given a ``target`` net income, and according to the ``varying`` gross
     income. Optionally, a ``trim`` can be applied consisting of the lower and
@@ -95,8 +95,8 @@ def marginal_rate(
         array([nan, 0.5])
 
     """
-    marginal_rate: Array[numpy.float64]
 
+    marginal_rate: t.Array[numpy.float32]
     marginal_rate = +1 - (target[:-1] - target[1:]) / (varying[:-1] - varying[1:])
 
     if trim is not None:
@@ -113,3 +113,6 @@ def marginal_rate(
         )
 
     return marginal_rate
+
+
+__all__ = ["average_rate", "marginal_rate"]

openfisca_core/commons/types.py

@@ -0,0 +1,3 @@
+from openfisca_core.types import Array, ArrayLike
+
+__all__ = ["Array", "ArrayLike"]

openfisca_core/entities/_core_entity.py

@@ -1,7 +1,9 @@
 from __future__ import annotations
 
+from typing import ClassVar
+
+import abc
 import os
-from abc import abstractmethod
 
 from . import types as t
 from .role import Role
@@ -12,29 +14,30 @@ class _CoreEntity:
 
     #: A key to identify the entity.
     key: t.EntityKey
+
     #: The ``key``, pluralised.
-    plural: t.EntityPlural | None
+    plural: t.EntityPlural
 
     #: A summary description.
-    label: str | None
+    label: str
 
     #: A full description.
-    doc: str | None
+    doc: str
 
     #: Whether the entity is a person or not.
-    is_person: bool
+    is_person: ClassVar[bool]
 
     #: A TaxBenefitSystem instance.
-    _tax_benefit_system: t.TaxBenefitSystem | None = None
+    _tax_benefit_system: None | t.TaxBenefitSystem = None
 
-    @abstractmethod
+    @abc.abstractmethod
     def __init__(
         self,
-        key: str,
-        plural: str,
-        label: str,
-        doc: str,
-        *args: object,
+        __key: str,
+        __plural: str,
+        __label: str,
+        __doc: str,
+        *__args: object,
     ) -> None: ...
 
     def __repr__(self) -> str:
@@ -46,7 +49,7 @@ def set_tax_benefit_system(self, tax_benefit_system: t.TaxBenefitSystem) -> None
 
     def get_variable(
         self,
-        variable_name: str,
+        variable_name: t.VariableName,
         check_existence: bool = False,
     ) -> t.Variable | None:
         """Get a ``variable_name`` from ``variables``."""
@@ -57,16 +60,20 @@ def get_variable(
             )
         return self._tax_benefit_system.get_variable(variable_name, check_existence)
 
-    def check_variable_defined_for_entity(self, variable_name: str) -> None:
+    def check_variable_defined_for_entity(self, variable_name: t.VariableName) -> None:
         """Check if ``variable_name`` is defined for ``self``."""
-        variable: t.Variable | None
-        entity: t.CoreEntity
-
-        variable = self.get_variable(variable_name, check_existence=True)
+        entity: None | t.CoreEntity = None
+        variable: None | t.Variable = self.get_variable(
+            variable_name,
+            check_existence=True,
+        )
 
         if variable is not None:
             entity = variable.entity
 
+        if entity is None:
+            return
+
         if entity.key != self.key:
             message = (
                 f"You tried to compute the variable '{variable_name}' for",
@@ -77,8 +84,12 @@ def check_variable_defined_for_entity(self, variable_name: str) -> None:
             )
             raise ValueError(os.linesep.join(message))
 
-    def check_role_validity(self, role: object) -> None:
+    @staticmethod
+    def check_role_validity(role: object) -> None:
         """Check if a ``role`` is an instance of Role."""
         if role is not None and not isinstance(role, Role):
             msg = f"{role} is not a valid role"
             raise ValueError(msg)
+
+
+__all__ = ["_CoreEntity"]