From 08bbb832d08f06a103dacba60d96a5f6e6fe5942 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Wed, 16 May 2012 07:50:22 +0000
Subject: [PATCH] more query cleanup

---
 hledger-lib/Hledger/Data/Query.hs | 120 ++++++++++++++++--------------
 1 file changed, 63 insertions(+), 57 deletions(-)

diff --git a/hledger-lib/Hledger/Data/Query.hs b/hledger-lib/Hledger/Data/Query.hs
index 881b68d94..383814072 100644
--- a/hledger-lib/Hledger/Data/Query.hs
+++ b/hledger-lib/Hledger/Data/Query.hs
@@ -1,36 +1,35 @@
 {-|
 
-More generic matching, done in one step, unlike FilterSpec and filterJournal*. 
-Currently used only by hledger-web.
+A general query system for matching items by standard criteria, in one
+step unlike FilterSpec and filterJournal*.  Currently used by hledger-web.
 
 -}
 
 module Hledger.Data.Query (
+  -- * Query and QueryOpt
   Query(..),
+  QueryOpt(..),
   queryIsNull,
-  queryIsStartDateOnly,
   queryStartDate,
-  matchesTransaction,
-  matchesPosting,
+  queryIsStartDateOnly,
   inAccount,
   inAccountQuery,
+  -- * parsing
+  parseQuery,
+  -- * matching
+  matchesTransaction,
+  matchesPosting,
+  -- * tests
   tests_Hledger_Data_Query
 )
 where
 import Data.Either
 import Data.List
--- import Data.Map (findWithDefault, (!))
 import Data.Maybe
--- import Data.Ord
 import Data.Time.Calendar
--- import Data.Time.LocalTime
--- import Data.Tree
 import Safe (readDef, headDef)
--- import System.Time (ClockTime(TOD))
 import Test.HUnit
 import Text.ParserCombinators.Parsec
--- import Text.Printf
--- import qualified Data.Map as Map
 
 import Hledger.Utils
 import Hledger.Data.Types
@@ -42,6 +41,7 @@ import Hledger.Data.Posting
 import Hledger.Data.Transaction
 -- import Hledger.Data.TimeLog
 
+
 -- | A query is a composition of search criteria, which can be used to
 -- match postings, transactions, accounts and more.
 data Query = Any              -- ^ always match
@@ -69,6 +69,49 @@ data QueryOpt = QueryOptInAcctOnly AccountName  -- ^ show an account register fo
            -- | QueryOptEffectiveDate  -- ^ show effective dates instead of actual dates
     deriving (Show, Eq)
 
+-- | Does this query match everything ?
+queryIsNull Any = True
+queryIsNull (And []) = True
+queryIsNull (Not (Or [])) = True
+queryIsNull _ = False
+
+-- | What start date does this query specify, if any ?
+-- If the query is an OR expression, returns the earliest of the alternatives.
+-- When the flag is true, look for a starting effective date instead.
+queryStartDate :: Bool -> Query -> Maybe Day
+queryStartDate effective (Or ms) = earliestMaybeDate $ map (queryStartDate effective) ms
+queryStartDate effective (And ms) = latestMaybeDate $ map (queryStartDate effective) ms
+queryStartDate False (Date (DateSpan (Just d) _)) = Just d
+queryStartDate True (EDate (DateSpan (Just d) _)) = Just d
+queryStartDate _ _ = Nothing
+
+-- | Does this query specify a start date and nothing else (that would
+-- filter postings prior to the date) ?
+-- When the flag is true, look for a starting effective date instead.
+queryIsStartDateOnly :: Bool -> Query -> Bool
+queryIsStartDateOnly _ Any = False
+queryIsStartDateOnly _ None = False
+queryIsStartDateOnly effective (Or ms) = and $ map (queryIsStartDateOnly effective) ms
+queryIsStartDateOnly effective (And ms) = and $ map (queryIsStartDateOnly effective) ms
+queryIsStartDateOnly False (Date (DateSpan (Just _) _)) = True
+queryIsStartDateOnly True (EDate (DateSpan (Just _) _)) = True
+queryIsStartDateOnly _ _ = False
+
+-- | What is the earliest of these dates, where Nothing is earliest ?
+earliestMaybeDate :: [Maybe Day] -> Maybe Day
+earliestMaybeDate = headDef Nothing . sortBy compareMaybeDates
+
+-- | What is the latest of these dates, where Nothing is earliest ?
+latestMaybeDate :: [Maybe Day] -> Maybe Day
+latestMaybeDate = headDef Nothing . sortBy (flip compareMaybeDates)
+
+-- | Compare two maybe dates, Nothing is earliest.
+compareMaybeDates :: Maybe Day -> Maybe Day -> Ordering
+compareMaybeDates Nothing Nothing = EQ
+compareMaybeDates Nothing (Just _) = LT
+compareMaybeDates (Just _) Nothing = GT
+compareMaybeDates (Just a) (Just b) = compare a b
+
 -- | The account we are currently focussed on, if any, and whether subaccounts are included.
 -- Just looks at the first query option.
 inAccount :: [QueryOpt] -> Maybe (AccountName,Bool)
@@ -83,6 +126,12 @@ inAccountQuery [] = Nothing
 inAccountQuery (QueryOptInAcctOnly a:_) = Just $ Acct $ accountNameToAccountOnlyRegex a
 inAccountQuery (QueryOptInAcct a:_) = Just $ Acct $ accountNameToAccountRegex a
 
+-- -- | Convert a query to its inverse.
+-- negateQuery :: Query -> Query
+-- negateQuery =  Not
+
+-- query parsing
+
 -- -- | A query restricting the account(s) to be shown in the sidebar, if any.
 -- -- Just looks at the first query option.
 -- showAccountMatcher :: [QueryOpt] -> Maybe Query
@@ -185,9 +234,7 @@ parseBool s = s `elem` truestrings
 truestrings :: [String]
 truestrings = ["1","t","true"]
 
--- -- | Convert a query to its inverse.
--- negateQuery :: Query -> Query
--- negateQuery =  Not
+-- query matching
 
 -- | Does the match expression match this posting ?
 matchesPosting :: Query -> Posting -> Bool
@@ -239,48 +286,7 @@ matchesAccount (And ms) a = all (`matchesAccount` a) ms
 matchesAccount (Acct r) a = regexMatchesCI r a
 matchesAccount _ _ = False
 
--- | What start date does this query specify, if any ?
--- If the query is an OR expression, returns the earliest of the alternatives.
--- When the flag is true, look for a starting effective date instead.
-queryStartDate :: Bool -> Query -> Maybe Day
-queryStartDate effective (Or ms) = earliestMaybeDate $ map (queryStartDate effective) ms
-queryStartDate effective (And ms) = latestMaybeDate $ map (queryStartDate effective) ms
-queryStartDate False (Date (DateSpan (Just d) _)) = Just d
-queryStartDate True (EDate (DateSpan (Just d) _)) = Just d
-queryStartDate _ _ = Nothing
-
--- | Does this query specify a start date and nothing else (that would
--- filter postings prior to the date) ?
--- When the flag is true, look for a starting effective date instead.
-queryIsStartDateOnly :: Bool -> Query -> Bool
-queryIsStartDateOnly _ Any = False
-queryIsStartDateOnly _ None = False
-queryIsStartDateOnly effective (Or ms) = and $ map (queryIsStartDateOnly effective) ms
-queryIsStartDateOnly effective (And ms) = and $ map (queryIsStartDateOnly effective) ms
-queryIsStartDateOnly False (Date (DateSpan (Just _) _)) = True
-queryIsStartDateOnly True (EDate (DateSpan (Just _) _)) = True
-queryIsStartDateOnly _ _ = False
-
--- | Does this query match everything ?
-queryIsNull Any = True
-queryIsNull (And []) = True
-queryIsNull (Not (Or [])) = True
-queryIsNull _ = False
-
--- | What is the earliest of these dates, where Nothing is earliest ?
-earliestMaybeDate :: [Maybe Day] -> Maybe Day
-earliestMaybeDate = headDef Nothing . sortBy compareMaybeDates
-
--- | What is the latest of these dates, where Nothing is earliest ?
-latestMaybeDate :: [Maybe Day] -> Maybe Day
-latestMaybeDate = headDef Nothing . sortBy (flip compareMaybeDates)
-
--- | Compare two maybe dates, Nothing is earliest.
-compareMaybeDates :: Maybe Day -> Maybe Day -> Ordering
-compareMaybeDates Nothing Nothing = EQ
-compareMaybeDates Nothing (Just _) = LT
-compareMaybeDates (Just _) Nothing = GT
-compareMaybeDates (Just a) (Just b) = compare a b
+-- tests
 
 tests_Hledger_Data_Query :: Test
 tests_Hledger_Data_Query = TestList