64 lines
1.4 KiB
ReStructuredText
64 lines
1.4 KiB
ReStructuredText
Enumerations
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############
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.. py:module:: amaranth.lib.enum
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The :mod:`amaranth.lib.enum` module is a drop-in replacement for the standard :mod:`enum` module that provides extended :class:`Enum`, :class:`IntEnum`, :class:`Flag`, and :class:`IntFlag` classes with the ability to specify a shape explicitly.
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A shape can be specified for an enumeration with the ``shape=`` keyword argument:
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.. testsetup::
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from amaranth import *
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.. testcode::
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from amaranth.lib import enum
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class Funct(enum.Enum, shape=4):
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ADD = 0
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SUB = 1
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MUL = 2
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.. doctest::
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>>> Shape.cast(Funct)
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unsigned(4)
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Any :ref:`constant-castable <lang-constcasting>` expression can be used as the value of a member:
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.. testcode::
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class Op(enum.Enum, shape=1):
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REG = 0
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IMM = 1
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class Instr(enum.Enum, shape=5):
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ADD = Cat(Funct.ADD, Op.REG)
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ADDI = Cat(Funct.ADD, Op.IMM)
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SUB = Cat(Funct.SUB, Op.REG)
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SUBI = Cat(Funct.SUB, Op.IMM)
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...
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.. doctest::
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>>> Instr.SUBI
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<Instr.SUBI: 17>
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This module is a drop-in replacement for the standard :mod:`enum` module, and re-exports all of its members (not just the ones described below). In an Amaranth project, all ``import enum`` statements may be replaced with ``from amaranth.lib import enum``.
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Metaclass
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=========
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.. autoclass:: EnumMeta()
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Base classes
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============
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.. autoclass:: Enum()
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.. autoclass:: IntEnum()
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.. autoclass:: Flag()
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.. autoclass:: IntFlag()
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