42 lines
1.3 KiB
Haskell
42 lines
1.3 KiB
Haskell
{-|
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A 'Commodity' is a symbol and a conversion rate relative to the
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dollar. Commodity symbols are parsed from the ledger file, rates are
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currently hard-coded.
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-}
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module Ledger.Commodity
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where
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import qualified Data.Map as Map
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import Ledger.Utils
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import Ledger.Types
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commoditytests = TestList [
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]
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unknown = Commodity {symbol="",rate=1,side=L,spaced=False,precision=0}
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dollar = Commodity {symbol="$",rate=1,side=L,spaced=False,precision=2}
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euro = Commodity {symbol="EUR",rate=0.760383,side=L,spaced=False,precision=2}
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pound = Commodity {symbol="£",rate=0.512527,side=L,spaced=False,precision=2}
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hour = Commodity {symbol="h",rate=100,side=R,spaced=False,precision=1}
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-- | convenient amount constructors
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unknowns = Amount unknown
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dollars = Amount dollar
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euros = Amount euro
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pounds = Amount pound
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hours = Amount hour
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defaultcommodities = [unknown, dollar, euro, pound, hour]
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defaultcommoditiesmap :: Map.Map String Commodity
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defaultcommoditiesmap = Map.fromList [(symbol c :: String, c :: Commodity) | c <- defaultcommodities]
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comm :: String -> Commodity
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comm symbol = Map.findWithDefault (error "commodity lookup failed") symbol defaultcommoditiesmap
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conversionRate :: Commodity -> Commodity -> Double
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conversionRate oldc newc = (rate newc) / (rate oldc)
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