Add 'group' combinator

ChangeLog.md

@@ -1,5 +1,8 @@
 # Changelog for lens-regex-pcre
 
+# UNRELEASED 0.3.2.0
+Add 'group = groups . ix n' for accessing a single group.
+
 # 0.3.1.0 
 Match -> Match text
 Added regexBS to run regex on ByteStrings directly

README.md

@@ -18,7 +18,7 @@ txt :: Text
 txt = "raindrops on roses and whiskers on kittens"
 
 -- Search
-λ> has (regex [rx|whisk|]) txt
+λ> has (regex [rx|whisk|] . match) txt
 True
 
 -- Get matches

lens-regex-pcre.cabal

@@ -1,10 +1,10 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.1.
+-- This file has been generated from package.yaml by hpack version 0.31.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: c1baf100f3d2d1c413b88695a96d578b0a8d18aace0929759a5428dcfa30b1f1
+-- hash: 3bb90fc0aad7064897c98047f082798825404f2187c6a0ac1901de2412b29f3e
 
 name:           lens-regex-pcre
 version:        0.3.1.0
@@ -37,12 +37,12 @@ library
   ghc-options: -Wall
   build-depends:
       base >=4.7 && <5
+    , bytestring
     , lens
     , pcre-heavy
     , pcre-light
     , template-haskell
     , text
-    , bytestring
   default-language: Haskell2010
 
 test-suite lens-regex-pcre-test
@@ -55,6 +55,7 @@ test-suite lens-regex-pcre-test
   ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base >=4.7 && <5
+    , bytestring
     , hspec
     , lens
     , lens-regex-pcre

src/Control/Lens/Regex.hs

@@ -19,9 +19,10 @@ module Control.Lens.Regex
     , regexBS
     , match
     , groups
+    , group
     , matchAndGroups
 
-    -- * Compiling regex
+    -- * Compiling regexes
     , rx
     , mkRegexQQ
     , compile
@@ -32,7 +33,7 @@ module Control.Lens.Regex
     , Regex
     ) where
 
-import qualified Data.Text as T hiding (index)
+import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
 import qualified Data.Text.Encoding.Error as T
 import qualified Data.ByteString as BS
@@ -70,7 +71,7 @@ type GroupRanges = [(Int, Int)]
 -- >>> "raindrops on roses and whiskers on kittens" ^.. regex [rx|(\w+) on (\w+)|] . groups
 -- [["raindrops","roses"],["whiskers","kittens"]]
 --
--- You can access a specific group by combining with `ix`
+-- You can access a specific group combining with 'ix', or just use 'group' instead
 --
 -- >>> "raindrops on roses and whiskers on kittens" ^.. regex [rx|(\w+) on (\w+)|] . groups .  ix 1
 -- ["roses","kittens"]
@@ -92,6 +93,21 @@ type GroupRanges = [(Int, Int)]
 groups :: Traversal' (Match text) [text]
 groups = partsOf (traversed . _Right)
 
+-- | Access a specific group of a match. Numbering starts at 0.
+--
+-- See 'groups' for more info on grouping
+--
+-- >>> "key:value, a:b" ^.. regex [rx|(\w+):(\w+)|] . group 0
+-- ["key","a"]
+--
+-- >>> "key:value, a:b" ^.. regex [rx|(\w+):(\w+)|] . group 1
+-- ["value","b"]
+--
+-- >>> "key:value, a:b" & regex [rx|(\w+):(\w+)|] . group 1 %~ T.toUpper
+-- "key:VALUE, a:B" 
+group :: Int -> Traversal' (Match text) text
+group n = groups . ix n
+
 -- | Traverse each match
 --
 --  Get a match if one exists:

stack.yaml

@@ -17,7 +17,7 @@
 #
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
-resolver: lts-13.24
+resolver: lts-14.1
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.

stack.yaml.lock

@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    size: 523448
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/14/1.yaml
+    sha256: 0045b9bae36c3bb2dd374c29b586389845af1557eea0423958d152fc500d4fbf
+  original: lts-14.1

test/Spec.hs

@@ -109,6 +109,15 @@ main = hspec $ do
                 ("raindrops on roses and whiskers on kittens" & regex [rx|(\w+) on (\w+)|] . groups %~ reverse)
                 `shouldBe` "roses on raindrops and kittens on whiskers"
 
+    describe "group" $ do
+        it "should get a single group" $ do
+                "a:b c:d" ^.. regex [rx|(\w):(\w)|] . group 1
+                `shouldBe` ["b", "d"]
+
+        it "should set a single group" $ do
+                "a:b c:d" & regex [rx|(\w):(\w)|] . group 1 %~ T.toUpper
+                `shouldBe` "a:B c:D"
+
         describe "traversed" $ do
             it "should allow setting all group matches" $ do
                 ("one two three" & regex [rx|(\w+) (\w+)|] . groups . traversed .~ "new")