:py:mod:`raesl.compile.ast.exprs`
=================================

.. py:module:: raesl.compile.ast.exprs

.. autoapi-nested-parse::

   Expressions to store and reason about values and boundaries.



Module Contents
---------------

Classes
~~~~~~~

.. autoapisummary::

   raesl.compile.ast.exprs.DataValue
   raesl.compile.ast.exprs.Value
   raesl.compile.ast.exprs.VariableValue
   raesl.compile.ast.exprs.Expression
   raesl.compile.ast.exprs.Comparison
   raesl.compile.ast.exprs.RelationComparison
   raesl.compile.ast.exprs.ObjectiveComparison
   raesl.compile.ast.exprs.Disjunction




Attributes
~~~~~~~~~~

.. autoapisummary::

   raesl.compile.ast.exprs._MATH_OP_TRANSLATE


.. py:class:: DataValue


   Some kind of data value. Do not use this, but use a derived class instead.

   .. py:method:: get_units() -> Optional[Set[str]]
      :abstractmethod:

      Obtain the units of the value. Gives a set of names without square brackets
      where lack of units results in the empty set, and not supporting units gives
      None.

      :returns: Names of the available units without square brackets or None.



.. py:class:: Value(value: raesl.compile.scanner.Token, unit: Optional[raesl.compile.scanner.Token] = None)


   Bases: :py:obj:`DataValue`

   A value with an optional unit. Don't modify these objects in-place, create a new
   object instead.

   :param value: Stored value as text.
   :param unit: Either None or text describing the unit. Treat as read-only, as changing
                it may break the cache.

   .. attribute:: _unit_cache

      Units of the literal after normalizing self.unit. Computed on
      demand.

   .. py:method:: get_units() -> Optional[Set[str]]

      Obtain the units of the value. Gives a set of names without square brackets
      where lack of units results in the empty set, and not supporting units gives
      None.

      :returns: Names of the available units without square brackets or None.


   .. py:method:: __eq__(other)

      Return self==value.


   .. py:method:: __repr__()

      Return repr(self).



.. py:class:: VariableValue(var_tok: raesl.compile.scanner.Token)


   Bases: :py:obj:`DataValue`

   Class representing a variable or parameter as value.

   :param var_tok: Token stating the possibly dotted name of the variable.
   :param var_node: If not None, the node represented by the object. Set during type
                    checking.

   .. py:method:: get_units() -> Optional[Set[str]]

      Obtain the units of the value. Gives a set of names without square brackets
      where lack of units results in the empty set, and not supporting units gives
      None.

      :returns: Names of the available units without square brackets or None.



.. py:class:: Expression


   Base class of an expression.


.. py:class:: Comparison(is_constraint: bool)


   Bases: :py:obj:`Expression`

   Class storing a comparison.

   :param is_constraint: Whether the comparison is considered to be a constraint rather
                         than a requirement.


.. py:data:: _MATH_OP_TRANSLATE

   

.. py:class:: RelationComparison(is_constraint: bool, lhs_var: VariableValue, isaux_tok: raesl.compile.scanner.Token, cmp_tok: raesl.compile.scanner.Token, rhs_varval: DataValue)


   Bases: :py:obj:`Comparison`

   A relation between a variable and either a value or a variable.

   :param is_constraint: Whether the comparison is considered to be a constraint rather
                         than a requirement.
   :param lhs_var: Left hand side variable being compared.
   :param isaux_tok: 'is' for a constraint, else the aux word for expressing strength
                     of the comparison.
   :param cmp_tok: One of the key words that expression the comparison to perform.
   :param math_compare: Translated 'cmp_tok', with the ascii math text.
   :param rhs_varval: Right hand side variable or value.

   .. py:method:: get_location() -> raesl.types.Location

      Return a location to point at the comparison for error reporting purposes.



.. py:class:: ObjectiveComparison(lhs_var: VariableValue, aux_tok: raesl.compile.scanner.Token, maximize: bool)


   Bases: :py:obj:`Comparison`

   An intended direction for a variable. Note that the 'maximize' parameter
   controls both the 'maximize' and 'minimize' desires.

   :param lhs_var: Variable with the objective.
   :param aux_tok: One of the auxiliary verbs expressing strength of the objective.
   :param maximize: If set the comparison expresses the desire to maximize the variable.

   .. attribute:: minimize

      Opposite of maximize.

   .. py:property:: minimize
      :type: bool


   .. py:method:: get_location() -> raesl.types.Location

      Return a location to point at the comparison for error reporting purposes.



.. py:class:: Disjunction(childs: Sequence[Expression])


   Bases: :py:obj:`Expression`

   Disjunctive expression (also known as 'or' expression).
   It is true iff at least one of it child expressions is true.

   :param childs: Child expressions of the disjunction. It is recommended to have at
                  least two children in an object.