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# ==================================================================================================================== #
# __ ___ _ ____ _ __ __ _ _ #
# _ __ _ \ \ / / | | | _ \| | | \/ | ___ __| | ___| | #
# | '_ \| | | \ \ / /| |_| | | | | | | |\/| |/ _ \ / _` |/ _ \ | #
# | |_) | |_| |\ V / | _ | |_| | |___| | | | (_) | (_| | __/ | #
# | .__/ \__, | \_/ |_| |_|____/|_____|_| |_|\___/ \__,_|\___|_| #
# |_| |___/ #
# ==================================================================================================================== #
# Authors: #
# Patrick Lehmann #
# #
# License: #
# ==================================================================================================================== #
# Copyright 2017-2023 Patrick Lehmann - Boetzingen, Germany #
# Copyright 2016-2017 Patrick Lehmann - Dresden, Germany #
# #
# Licensed under the Apache License, Version 2.0 (the "License"); #
# you may not use this file except in compliance with the License. #
# You may obtain a copy of the License at #
# #
# http://www.apache.org/licenses/LICENSE-2.0 #
# #
# Unless required by applicable law or agreed to in writing, software #
# distributed under the License is distributed on an "AS IS" BASIS, #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
# See the License for the specific language governing permissions and #
# limitations under the License. #
# #
# SPDX-License-Identifier: Apache-2.0 #
# ==================================================================================================================== #
#
"""
This module contains parts of an abstract document language model for VHDL.
Objects are constants, variables, signals and files.
"""
from typing import Iterable, Optional as Nullable
from pyTooling.Decorators import export
from pyTooling.MetaClasses import ExtendedType
from pyTooling.Graph import Vertex
from pyVHDLModel.Base import ModelEntity, MultipleNamedEntityMixin, DocumentedEntityMixin, ExpressionUnion
from pyVHDLModel.Symbol import Symbol
@export
class Obj(ModelEntity, MultipleNamedEntityMixin, DocumentedEntityMixin):
"""
Base-class for all objects (constants, signals, variables and files) in VHDL.
An object (syntax element) can define multiple objects (semantic elements) in a single declaration, thus
:class:`~pyVHDLModel.Base.MultipleNamedEntityMixin` is inherited. All objects can be documented, thus
:class:`~pyVHDLModel.Base.DocumentedEntityMixin` is inherited too.
Each object references a subtype via :data:`_subtype`.
Objects are elements in the type and object graph, thus a reference to a vertex in that graph is stored in
:data:`__objectVertex`.
"""
_subtype: Symbol
_objectVertex: Nullable[Vertex]
def __init__(self, identifiers: Iterable[str], subtype: Symbol, documentation: str = None):
super().__init__()
MultipleNamedEntityMixin.__init__(self, identifiers)
DocumentedEntityMixin.__init__(self, documentation)
self._subtype = subtype
subtype._parent = self
self._objectVertex = None
@property
def Subtype(self) -> Symbol:
return self._subtype
@property
def ObjectVertex(self) -> Nullable[Vertex]:
return self._objectVertex
@export
class WithDefaultExpressionMixin(metaclass=ExtendedType, mixin=True):
"""
A ``WithDefaultExpression`` is a mixin-class for all objects declarations accepting default expressions.
The default expression is referenced by :data:`__defaultExpression`. If no default expression is present, this field
is ``None``.
"""
_defaultExpression: Nullable[ExpressionUnion]
def __init__(self, defaultExpression: ExpressionUnion = None):
self._defaultExpression = defaultExpression
if defaultExpression is not None:
defaultExpression._parent = self
@property
def DefaultExpression(self) -> Nullable[ExpressionUnion]:
return self._defaultExpression
@export
class BaseConstant(Obj):
"""
Base-class for all constants (normal and deferred constants) in VHDL.
"""
@export
class Constant(BaseConstant, WithDefaultExpressionMixin):
"""
Represents a constant.
As constants (always) have a default expression, the class :class:`~pyVHDLModel.Object.WithDefaultExpressionMixin` is inherited.
.. admonition:: Example
.. code-block:: VHDL
constant BITS : positive := 8;
"""
def __init__(self, identifiers: Iterable[str], subtype: Symbol, defaultExpression: ExpressionUnion = None, documentation: str = None):
super().__init__(identifiers, subtype, documentation)
WithDefaultExpressionMixin.__init__(self, defaultExpression)
@export
class DeferredConstant(BaseConstant):
"""
Represents a deferred constant.
Deferred constants are forward declarations for a (complete) constant declaration, thus it contains a
field :data:`__constantReference` to the complete constant declaration.
.. admonition:: Example
.. code-block:: VHDL
constant BITS : positive;
"""
_constantReference: Nullable[Constant]
def __init__(self, identifiers: Iterable[str], subtype: Symbol, documentation: str = None):
super().__init__(identifiers, subtype, documentation)
@property
def ConstantReference(self) -> Nullable[Constant]:
return self._constantReference
def __str__(self) -> str:
return f"constant {', '.join(self._identifiers)} : {self._subtype}"
@export
class Variable(Obj, WithDefaultExpressionMixin):
"""
Represents a variable.
As variables might have a default expression, the class :class:`~pyVHDLModel.Object.WithDefaultExpressionMixin` is inherited.
.. admonition:: Example
.. code-block:: VHDL
variable result : natural := 0;
"""
def __init__(self, identifiers: Iterable[str], subtype: Symbol, defaultExpression: ExpressionUnion = None, documentation: str = None):
super().__init__(identifiers, subtype, documentation)
WithDefaultExpressionMixin.__init__(self, defaultExpression)
@export
class SharedVariable(Obj):
"""
Represents a shared variable.
.. todo:: Shared variable object not implemented.
"""
@export
class Signal(Obj, WithDefaultExpressionMixin):
"""
Represents a signal.
As signals might have a default expression, the class :class:`~pyVHDLModel.Object.WithDefaultExpressionMixin` is inherited.
.. admonition:: Example
.. code-block:: VHDL
signal counter : unsigned(7 downto 0) := '0';
"""
def __init__(self, identifiers: Iterable[str], subtype: Symbol, defaultExpression: ExpressionUnion = None, documentation: str = None):
super().__init__(identifiers, subtype, documentation)
WithDefaultExpressionMixin.__init__(self, defaultExpression)
@export
class File(Obj):
"""
Represents a file.
.. todo:: File object not implemented.
"""
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