54 lines
1.6 KiB
Haskell
54 lines
1.6 KiB
Haskell
{-# LANGUAGE CPP #-}
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{-# LANGUAGE DeriveAnyClass #-}
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{-# LANGUAGE DeriveDataTypeable #-}
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{-# LANGUAGE DeriveGeneric #-}
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{-# LANGUAGE OverloadedStrings #-}
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module Nix.Atoms where
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#ifdef MIN_VERSION_serialise
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import Codec.Serialise
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#endif
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import Control.DeepSeq
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import Data.Data
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import Data.Fixed (mod')
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import Data.Hashable
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import Data.Text ( Text
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, pack
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)
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import GHC.Generics
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-- | Atoms are values that evaluate to themselves. This means that
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-- they appear in both the parsed AST (in the form of literals) and
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-- the evaluated form.
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data NAtom
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-- | An URI like @https://example.com@.
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= NURI Text
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-- | An integer. The c nix implementation currently only supports
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-- integers that fit in the range of 'Int64'.
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| NInt Integer
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-- | A floating point number
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| NFloat Float
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-- | Booleans. @false@ or @true@.
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| NBool Bool
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-- | Null values. There's only one of this variant: @null@.
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| NNull
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deriving (Eq, Ord, Generic, Typeable, Data, Show, Read, NFData,
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Hashable)
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#ifdef MIN_VERSION_serialise
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instance Serialise NAtom
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#endif
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-- | Translate an atom into its nix representation.
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atomText :: NAtom -> Text
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atomText (NURI t) = t
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atomText (NInt i) = pack (show i)
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atomText (NFloat f) = pack (showNixFloat f)
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where
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showNixFloat x
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| x `mod'` 1 /= 0 = show x
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| otherwise = show (truncate x :: Int)
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atomText (NBool b) = if b then "true" else "false"
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atomText NNull = "null"
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