From 93ced249b369b352f2f1df476e911125e7f1406f Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Sat, 18 Oct 2008 19:30:07 +0000
Subject: [PATCH] commodity cleanup

---
 Ledger/Commodity.hs | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/Ledger/Commodity.hs b/Ledger/Commodity.hs
index 8de407e5f..056f1224e 100644
--- a/Ledger/Commodity.hs
+++ b/Ledger/Commodity.hs
@@ -1,9 +1,9 @@
 {-|
 
 A 'Commodity' is a symbol representing a currency or some other kind of
-thing we are tracking, and some settings that tell how to display amounts
-of the commodity.  For the moment, commodities also include a hard-coded
-conversion rate relative to the dollar.
+thing we are tracking, and some display preferences that tell how to
+display 'Amount's of the commodity - is the symbol on the left or right,
+are thousands separated by comma, significant decimal places and so on.
 
 -}
 module Ledger.Commodity
@@ -13,15 +13,13 @@ import Ledger.Utils
 import Ledger.Types
 
 
--- for nullamt, autoamt, etc.
-unknown = Commodity {symbol="",side=L,spaced=False,comma=False,precision=0}
-
 -- convenient amount and commodity constructors, for tests etc.
 
-dollar  = Commodity {symbol="$",side=L,spaced=False,comma=False,precision=2}
+unknown = Commodity {symbol="",   side=L,spaced=False,comma=False,precision=0}
+dollar  = Commodity {symbol="$",  side=L,spaced=False,comma=False,precision=2}
 euro    = Commodity {symbol="EUR",side=L,spaced=False,comma=False,precision=2}
-pound   = Commodity {symbol="£",side=L,spaced=False,comma=False,precision=2}
-hour    = Commodity {symbol="h",side=R,spaced=False,comma=False,precision=1}
+pound   = Commodity {symbol="£",  side=L,spaced=False,comma=False,precision=2}
+hour    = Commodity {symbol="h",  side=R,spaced=False,comma=False,precision=1}
 
 dollars n = Amount dollar n Nothing
 euros n   = Amount euro n Nothing
@@ -30,13 +28,13 @@ hours n   = Amount hour n Nothing
 
 defaultcommodities = [dollar,  euro,  pound, hour, unknown]
 
-defaultcommoditiesmap :: Map.Map String Commodity
-defaultcommoditiesmap = Map.fromList [(symbol c :: String, c :: Commodity) | c <- defaultcommodities]
-
+-- | Look up one of the hard-coded default commodities. For use in tests.
 comm :: String -> Commodity
-comm symbol = Map.findWithDefault (error "commodity lookup failed") symbol defaultcommoditiesmap
+comm sym = fromMaybe 
+              (error "commodity lookup failed") 
+              $ find (\(Commodity{symbol=s}) -> s==sym) defaultcommodities
 
--- | Find the conversion rate between two commodities.
+-- | Find the conversion rate between two commodities. Currently returns 1.
 conversionRate :: Commodity -> Commodity -> Double
 conversionRate oldc newc = 1