roman-numerals 0.4.0.1 → 0.5.0

raw patch · 2 files changed

+80/−66 lines, 2 filesdep +textdep −mtlPVP ok

version bump matches the API change (PVP)

Dependencies added: text

Dependencies removed: mtl

API changes (from Hackage documentation)

Files

• Text/Numeral/Roman.hs +78/−64
• roman-numerals.cabal +2/−2

@@ -1,4 +1,5 @@-{-# LANGUAGE FlexibleContexts+{-# LANGUAGE CPP+           , FlexibleContexts            , NoImplicitPrelude            , OverloadedStrings            , UnicodeSyntax@@ -7,11 +8,10 @@ {-| Parsing and pretty printing of Roman numerals.  This module provides functions for parsing and pretty printing Roman-numerals. Because the notation of Roman numerals has varied through-the centuries this package allows for some customisation using a-configuration that is passed to the conversion functions. Exceptions-are dealt with by wrapping the results of conversions in the error-monad.+numerals. Because the notation of Roman numerals has varied through the+centuries this package allows for some customisation using a configuration that+is passed to the conversion functions. Exceptions are dealt with by wrapping the+results of conversions in the error monad.  Example: @@ -21,8 +21,8 @@ @  @-  \> 'fromRoman' \"MDCCXXIX\" &#x2237; Either String Integer-  Right 1729+  \> 'fromRoman' \"MDCCXXIX\" &#x2237; Maybe Integer+  Just 1729 @  @@@ -31,8 +31,8 @@ @  @-  \> 'fromRoman' \"Bla\" &#x2237; Either String Integer-  Left \"Roman.convertFrom: can't parse\"+  \> 'fromRoman' \"Bla\" &#x2237; Maybe Integer+  Nothing @  -}@@ -62,47 +62,56 @@ -------------------------------------------------------------------------------  -- from base:+import Control.Monad ( return, mzero ) import Data.Bool     ( Bool, otherwise )-import Data.Char     ( String ) import Data.Eq       ( Eq ) import Data.Function ( ($), flip, on ) import Data.List     ( sortBy, null, stripPrefix ) import Data.Maybe    ( Maybe(Nothing, Just), maybe ) import Data.Monoid   ( Monoid ) import Data.Ord      ( Ord, compare )-import Data.String   ( IsString, fromString )+import Data.String   ( IsString ) import Data.Tuple    ( snd )-import Control.Monad ( (>>=), (>>), return, fail )-import Prelude       ( Num, (+), (-), fromInteger, error )+import Prelude       ( Num, (+), (-), error ) +#if __GLASGOW_HASKELL__ < 700+import Control.Monad ( (>>=), (>>), fail )+import Data.String   ( fromString )+import Prelude       ( fromInteger )+#endif+ -- from base-unicode-symbols: import Data.Eq.Unicode       ( (≡) )-import Data.Function.Unicode ( (∘) )-import Data.Ord.Unicode      ( (≥), (≤) ) import Data.Monoid.Unicode   ( (∅), (⊕) )+import Data.Ord.Unicode      ( (≥), (≤) )  -- from bytestring:-import qualified Data.ByteString as BS+import qualified Data.ByteString      as BS  ( ByteString+                                             , isPrefixOf+                                             , drop, length, null +                                             )+import qualified Data.ByteString.Lazy as BSL ( ByteString+                                             , isPrefixOf+                                             , drop, length, null +                                             ) --- from monads-fd:-import Control.Monad.Error ( MonadError, throwError )+-- from text:+import qualified Data.Text      as T  ( Text, null, stripPrefix )+import qualified Data.Text.Lazy as TL ( Text, null, stripPrefix )   ------------------------------------------------------------------------------- -- Types ------------------------------------------------------------------------------- --- |A configuration with which the 'convertTo' and 'convertFrom'---  functions can be parameterized.+-- |A configuration with which the 'convertTo' and 'convertFrom' functions can+-- be parameterized. data NumeralConfig s n = NC     { -- |Symbol to represent the value 0.       ncZero ∷ s-      -- |A table of symbols and their numerical values. The table-      -- must be ordered in descending order of the value of the-      -- symbols. If any symbol is the empty string then 'convertFrom'-      -- will be &#x22a5;. If any symbol in this table is associated-      -- with the value 0 both the 'convertTo' and 'convertFrom'-      -- function will be &#x22a5;.+      -- |A table of symbols and their numerical values. The table must be+      -- ordered in descending order of the value of the symbols. If any symbol+      -- is the empty string then 'convertFrom' will be &#x22a5;.     , ncTable ∷ [(s, n)]     } @@ -117,16 +126,12 @@        , ncTable = sortBy (flip compare `on` snd) ((o, 1) : tab)        } + ------------------------------------------------------------------------------- -- Pretty printing ------------------------------------------------------------------------------- --- |Converts a number to a Roman numeral according to the given--- configuration. Numbers which are out of bounds will cause--- exceptions to be thrown. An exception will also be raised if no--- representation is possible with the given configuration. If the--- value of any symbol in the configuration is equal to 0 or a symbol--- is the empty string this function is undefined.+-- |Converts a number to a Roman numeral according to the given configuration. convertTo ∷ Monoid s ⇒ Ord n ⇒ Num n ⇒ NumeralConfig s n → n → s convertTo nc n     | n ≡ 0     = ncZero nc@@ -153,39 +158,51 @@  instance StripPrefix BS.ByteString where     spNull = BS.null-    spStripPrefix p s = let (h, t) = BS.breakSubstring p s-                        in if spNull h-                           then Just $ BS.drop (BS.length p) t-                           else Nothing+    spStripPrefix p s = if p `BS.isPrefixOf` s+                        then Just $ BS.drop (BS.length p) s+                        else Nothing +instance StripPrefix BSL.ByteString where+    spNull = BSL.null+    spStripPrefix p s = if p `BSL.isPrefixOf` s+                        then Just $ BSL.drop (BSL.length p) s+                        else Nothing++instance StripPrefix T.Text where+    spNull        = T.null+    spStripPrefix = T.stripPrefix++instance StripPrefix TL.Text where+    spNull        = TL.null+    spStripPrefix = TL.stripPrefix++ -- |Parses a string as a Roman numeral according to the given--- configuration. An exception will be thrown if the input is not a--- valid numeral.-convertFrom ∷ (Monoid s, StripPrefix s, Eq s, Ord n, Num n, MonadError String m)-            ⇒ NumeralConfig s n → s → m n+-- configuration. Result is 'Nothing' if the input is not a valid numeral.+convertFrom ∷ ( Monoid s, StripPrefix s, Eq s+              , Ord n, Num n+              )+            ⇒ NumeralConfig s n → s → Maybe n convertFrom nc s | ncZero nc ≡ s = return 0                  | otherwise = do n  ← (go 0 (ncTable nc) s)                                   if s ≡ convertTo nc n                                     then return n-                                    else errMsg "invalid Roman numeral"+                                    else mzero     where go n _  x | spNull x = return n-          go _ [] _            = errMsg "can't parse"+          go _ [] _            = mzero           go n tab@((sym, val) : ts) x = maybe (go n ts x)                                                (go (n + val) tab)                                                $ spStripPrefix sym x-          errMsg = throwError ∘ ("Roman.convertFrom: " ⊕) - ------------------------------------------------------------------------------- -- Default Configurations ------------------------------------------------------------------------------- --- |Configuration for Roman numerals as they are commonly used--- today. The value 0 is represented by the empty string. It can be--- interpreted as not writing down a number. This configuration is--- practically limited to the range [1..3999]. Smaller numbers will--- result in empty string. Larger numbers will result in repeated use--- of the \'M\' symbol.+-- |Configuration for Roman numerals as they are commonly used today. The value+-- 0 is represented by the empty string. It can be interpreted as not writing+-- down a number. This configuration is practically limited to the range+-- [1..3999]. Smaller numbers will result in an empty string. Larger numbers+-- will result in repeated use of the \'M\' symbol. modernRoman ∷ (IsString s, Ord n, Num n) ⇒ NumeralConfig s n modernRoman =     mkNumConfig ""@@ -204,12 +221,12 @@                 , ("M",  1000)                 ] --- |Configuration for Roman numerals that do not use the rule that a--- lower rank symbol can be placed before a higher rank symbol to--- denote the difference between them. Thus a numeral like \"IV\" will--- not be accepted or generated by this configuration. This--- configuration is practically limited to the range [1..3999]. Larger--- numbers will result in repeated use of the \'M\' symbol.+-- |Configuration for Roman numerals that do not use the rule that a lower rank+-- symbol can be placed before a higher rank symbol to denote the difference+-- between them. Thus a numeral like \"IV\" will not be accepted or generated by+-- this configuration. This configuration is practically limited to the range+-- [1..3999]. Smaller numbers will result in an empty string. Larger numbers+-- will result in repeated use of the \'M\' symbol. simpleRoman ∷ (IsString s, Ord n, Num n) ⇒ NumeralConfig s n simpleRoman =     mkNumConfig ""@@ -227,15 +244,12 @@ -- Utility ------------------------------------------------------------------------------- --- |Converts a number to a modern Roman numeral. See 'convertTo' for--- possible exceptions.+-- |Converts a number to a modern Roman numeral. toRoman ∷ (IsString s, Monoid s, Ord n, Num n) ⇒ n → s toRoman = convertTo modernRoman ---- |Parses a string as a modern Roman numeral. See 'convertFrom' for--- possible exceptions.+-- |Parses a string as a modern Roman numeral. fromRoman ∷ ( IsString s, Monoid s, StripPrefix s, Eq s-            , Ord n, Num n, MonadError String m-            ) ⇒ s → m n+            , Ord n, Num n+            ) ⇒ s → Maybe n fromRoman = convertFrom modernRoman

@@ -1,5 +1,5 @@ name:          roman-numerals-version:       0.4.0.1+version:       0.5.0 cabal-version: >= 1.6 build-type:    Simple stability:     stable@@ -26,7 +26,7 @@   build-depends: base                 >= 3.0.3.1 && < 4.4                , base-unicode-symbols >= 0.1.1   && < 0.3                , bytestring           >= 0.9.1   && < 0.10-               , mtl                  >= 2.0.0.0 && < 2.1+               , text                 >= 0.11    && < 0.12   exposed-modules: Text.Numeral.Roman   ghc-options: -Wall