lens-csv 0.1.0.0 → 0.1.1.0

raw patch · 3 files changed

+50/−4 lines, 3 filesPVP: major bump suggested

API removals or changes: PVP suggests a major version bump

API changes (from Hackage documentation)

Files

• README.md +7/−1
• lens-csv.cabal +2/−2
• src/Data/Csv/Lens.hs +41/−1

@@ -1,8 +1,14 @@ # lens-csv +* Docs are on [Hackage](http://hackage.haskell.org/package/lens-csv)++If you enjoy working with lenses (or need a hand learning how they work) my book [Optics By Example](https://leanpub.com/optics-by-example/) is a great place to learn more!++[![Optics By Example](./optics-by-example.png)](https://leanpub.com/optics-by-example/)+ A lensy layer on top of Cassava which affords streaming, traversable, CSV parsing. -Currently experimental (but working). Looking to improve error handling soon, currently parse failures are simply passed over by the traversals.+Still experimental (but working). Please file an issue if there are features the library doesn't support.  Example: 

@@ -4,10 +4,10 @@ -- -- see: https://github.com/sol/hpack ----- hash: a31186402cef7d6aaab23783b5d7c64b66ec7010836bec305199e7dc247053bf+-- hash: b42e502cf6962b3f20d061dba2fdfd5a45758c6358adab547e18494569d0324e  name:           lens-csv-version:        0.1.0.0+version:        0.1.1.0 description:    Please see the README on GitHub at <https://github.com/ChrisPenner/lens-csv#readme> homepage:       https://github.com/ChrisPenner/lens-csv#readme bug-reports:    https://github.com/ChrisPenner/lens-csv/issues

@@ -42,6 +42,7 @@     , CsvRecord     , cassavaNamed     , cassavaUnnamed+    , adjustingOutputHeaders     ) where  import Control.Lens@@ -177,10 +178,49 @@ -- -- >>> myCsv ^@.. namedCsv . headers -- [(0,"state_code"),(1,"population")]-headers :: IndexedFold Int (Csv' Name) Name+headers :: IndexedTraversal' Int (Csv' Name) Name -- Note to self, this could technically be a traversal, but since we don't want to reparse all -- records with the new headers we don't yet allow editing headers. headers  f (NamedCsv h xs) = flip NamedCsv xs <$> (h & traversed %%@~ indexed f)++-- | Allows rewriting/adding/removing headers on the CSV both before serializing+-- Note that rewriting a header name DOES NOT affect any of the records, it only affects the+-- choice and order of the columns in the output CSV. If you want to rename a column header+-- you must also rename the name of that field on all rows in the csv.+--+-- This is a limitation of cassava itself.+--+-- Examples:+--+-- Drop the first column:+--+-- >>> BL.lines (myCsv & namedCsv . adjustingOutputHeaders (view _tail) %~ id)+-- ["population\r","19540000\r","39560000\r"]+--+-- Add a new column with the population in millions+--+-- >>> import Data.Char (toLower)+-- >>> addStateLower m = M.insert "state_lower" (m ^. ix "state_code" . to (map toLower)) m+-- >>> :{+--  BL.lines (myCsv+--    & namedCsv+--    -- Add "state_lower" to output headers so it will be serialized+--    . adjustingOutputHeaders (<> pure "state_lower")+--    . rows+--    . _NamedRecord @(M.Map String String)+--    -- Add "state_lower" to each record+--    %~ addStateLower+--           )+-- :}+-- ["state_code,population,state_lower\r","NY,19540000,ny\r","CA,39560000,ca\r"]+--+-- Reverse column order+-- >>> BL.lines (myCsv & namedCsv . adjustingOutputHeaders (view reversed) %~ id)+-- ["population,state_code\r","19540000,NY\r","39560000,CA\r"]+--+adjustingOutputHeaders :: (Header -> Header) -- ^ Adjust headers for the serialization step+                    -> Iso' (Csv' Name) (Csv' Name)+adjustingOutputHeaders f = iso id (\(NamedCsv h xs) -> NamedCsv (f h) xs)  -- | An indexed traversal over each row of the csv as a 'CsvRecord'. Passes through -- a type witness signifying whether the records are 'Name' or 'Int' indexed.