57 lines
1.6 KiB
Nim
57 lines
1.6 KiB
Nim
# stew
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# Copyright 2023 Status Research & Development GmbH
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# Licensed under either of
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#
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
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#
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import std/[macros, options]
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type EnumStyle* {.pure.} = enum
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Numeric,
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AssociatedStrings
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func setMode(style: var Option[EnumStyle], s: EnumStyle, typ: auto) =
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if style.isNone:
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style = some s
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elif style.get != s:
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error("Mixed enum styles not supported for deserialization: " & $typ)
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else:
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discard
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macro enumStyle*(t: typedesc[enum]): untyped =
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let
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typ = t.getTypeInst[1]
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impl = typ.getImpl[2]
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expectKind impl, nnkEnumTy
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var style: Option[EnumStyle]
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for f in impl:
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case f.kind
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of nnkEmpty:
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continue
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of nnkIdent:
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error("Unexpected enum node for deserialization: " & $f.kind)
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of nnkSym:
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style.setMode(EnumStyle.Numeric, typ)
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of nnkEnumFieldDef:
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case f[1].kind
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of nnkIntLit:
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style.setMode(EnumStyle.Numeric, typ)
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of nnkStrLit:
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style.setMode(EnumStyle.AssociatedStrings, typ)
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else: error("Unexpected enum tuple for deserialization: " & $f[1].kind)
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else: error("Unexpected enum node for deserialization: " & $f.kind)
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if style.isNone:
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error("Cannot determine enum style for deserialization: " & $typ)
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case style.get
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of EnumStyle.Numeric:
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quote do:
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EnumStyle.Numeric
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of EnumStyle.AssociatedStrings:
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quote do:
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EnumStyle.AssociatedStrings
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