Add getLine to all Ropes

src/Data/Text/Lines/Internal.hs

@@ -244,9 +244,9 @@ lines (TextLines (Text arr off len) nls) = go off (U.toList nls)
 splitAtLine :: HasCallStack => Word -> TextLines -> (TextLines, TextLines)
 splitAtLine k = splitAtPosition (Position k 0)
 
--- | Get line with given index, O(1).
+-- | Get line with given 0-based index, O(1).
 -- The resulting Text does not contain newlines.
--- Returns "" if the line index is out of bounds
+-- Returns "" if the line index is out of bounds.
 --
 -- >>> :set -XOverloadedStrings
 -- >>> map (\l -> getLine l "fя𐀀\n☺bar\n\n") [0..3]

src/Data/Text/Mixed/Rope.hs

@@ -28,6 +28,7 @@ module Data.Text.Mixed.Rope
   , lines
   , lengthInLines
   , splitAtLine
+  , getLine
   -- * Code points
   , charLength
   , charSplitAt
@@ -562,3 +563,21 @@ utf16SplitAtPosition (Utf16.Position l c) rp = do
   let (beforeLine, afterLine) = splitAtLine l rp
   (beforeColumn, afterColumn) <- utf16SplitAt c afterLine
   Just (beforeLine <> beforeColumn, afterColumn)
+
+-- | Get a line by its 0-based index.
+-- Returns "" if the index is out of bounds.
+-- The result doesn't contain newline characters.
+--
+-- >>> :set -XOverloadedStrings
+-- >>> map (\l -> getLine l "foo\nbar\n😊😊\n\n") [0..3]
+-- ["foo","bar","😊😊",""]
+--
+getLine :: Word -> Rope -> Text
+getLine lineIdx rp =
+  case T.unsnoc firstLine of
+    Just (firstLineInit, '\n') -> firstLineInit
+    _ -> firstLine
+  where
+    (_, afterIndex) = splitAtLine lineIdx rp
+    (firstLineRope, _ ) = splitAtLine 1 afterIndex
+    firstLine = toText firstLineRope

src/Data/Text/Rope.hs

@@ -28,6 +28,7 @@ module Data.Text.Rope
   , lines
   , lengthInLines
   , splitAtLine
+  , getLine
   -- * Code points
   , length
   , splitAt
@@ -388,3 +389,21 @@ splitAtPosition (Position l c) rp = (beforeLine <> beforeColumn, afterColumn)
   where
     (beforeLine, afterLine) = splitAtLine l rp
     (beforeColumn, afterColumn) = splitAt c afterLine
+
+-- | Get a line by its 0-based index.
+-- Returns "" if the index is out of bounds.
+-- The result doesn't contain newline characters.
+--
+-- >>> :set -XOverloadedStrings
+-- >>> map (\l -> getLine l "foo\nbar\n😊😊\n\n") [0..3]
+-- ["foo","bar","😊😊",""]
+--
+getLine :: Word -> Rope -> Text
+getLine lineIdx rp =
+  case T.unsnoc firstLine of
+    Just (firstLineInit, '\n') -> firstLineInit
+    _ -> firstLine
+  where
+    (_, afterIndex) = splitAtLine lineIdx rp
+    (firstLineRope, _ ) = splitAtLine 1 afterIndex
+    firstLine = toText firstLineRope

src/Data/Text/Utf16/Rope.hs

@@ -28,6 +28,7 @@ module Data.Text.Utf16.Rope
   , lines
   , lengthInLines
   , splitAtLine
+  , getLine
   -- * UTF-16 code units
   , length
   , splitAt
@@ -391,3 +392,21 @@ splitAtPosition (Position l c) rp = do
   let (beforeLine, afterLine) = splitAtLine l rp
   (beforeColumn, afterColumn) <- splitAt c afterLine
   Just (beforeLine <> beforeColumn, afterColumn)
+
+-- | Get a line by its 0-based index.
+-- Returns "" if the index is out of bounds.
+-- The result doesn't contain newline characters.
+--
+-- >>> :set -XOverloadedStrings
+-- >>> map (\l -> getLine l "foo\nbar\n😊😊\n\n") [0..3]
+-- ["foo","bar","😊😊",""]
+--
+getLine :: Word -> Rope -> Text
+getLine lineIdx rp =
+  case T.unsnoc firstLine of
+    Just (firstLineInit, '\n') -> firstLineInit
+    _ -> firstLine
+  where
+    (_, afterIndex) = splitAtLine lineIdx rp
+    (firstLineRope, _ ) = splitAtLine 1 afterIndex
+    firstLine = toText firstLineRope

src/Data/Text/Utf8/Rope.hs

@@ -23,6 +23,7 @@ module Data.Text.Utf8.Rope
   , lines
   , lengthInLines
   , splitAtLine
+  , getLine
   -- * UTF-8 code units
   , length
   , splitAt
@@ -386,3 +387,21 @@ splitAtPosition (Position l c) rp = do
   let (beforeLine, afterLine) = splitAtLine l rp
   (beforeColumn, afterColumn) <- splitAt c afterLine
   Just (beforeLine <> beforeColumn, afterColumn)
+
+-- | Get a line by its 0-based index.
+-- Returns "" if the index is out of bounds.
+-- The result doesn't contain newline characters.
+--
+-- >>> :set -XOverloadedStrings
+-- >>> map (\l -> getLine l "foo\nbar\n😊😊\n\n") [0..3]
+-- ["foo","bar","😊😊",""]
+--
+getLine :: Word -> Rope -> Text
+getLine lineIdx rp =
+  case T.unsnoc firstLine of
+    Just (firstLineInit, '\n') -> firstLineInit
+    _ -> firstLine
+  where
+    (_, afterIndex) = splitAtLine lineIdx rp
+    (firstLineRope, _ ) = splitAtLine 1 afterIndex
+    firstLine = toText firstLineRope

test/CharRope.hs

@@ -7,13 +7,15 @@ module CharRope
   ( testSuite
   ) where
 
-import Prelude ()
+import Prelude ((+), (-))
 import Data.Function (($))
 import Data.Semigroup ((<>))
+import Data.Monoid (mempty)
+import qualified Data.List as L
 import qualified Data.Text.Lines as Lines
 import qualified Data.Text.Rope as Rope
 import Test.Tasty (testGroup, TestTree)
-import Test.Tasty.QuickCheck (testProperty, (===), (.&&.))
+import Test.Tasty.QuickCheck (Positive(..), conjoin, testProperty, (===), (.&&.))
 
 import Utils ()
 
@@ -48,4 +50,13 @@ testSuite = testGroup "Char Rope"
   , testProperty "splitAtPosition 2" $
     \i x -> case (Rope.splitAtPosition i x, Lines.splitAtPosition i (Lines.fromText $ Rope.toText x)) of
       ((y, z), (y', z')) -> Lines.fromText (Rope.toText y) === y' .&&. Lines.fromText (Rope.toText z) === z'
+
+  , testProperty "forall i in bounds: getLine i x == lines x !! i" $
+    \x -> let lns = Rope.lines x in
+      conjoin $ L.zipWith (\idx ln -> Rope.getLine idx x === ln) [0..] lns
+  , testProperty "forall i out of bounds: getLine i x == mempty" $
+    \x (Positive offset) ->
+      let maxIdx = L.genericLength (Rope.lines x) - 1
+          outOfBoundsIdx = maxIdx + offset
+      in Rope.getLine outOfBoundsIdx x === mempty
   ]

test/MixedRope.hs

@@ -11,13 +11,15 @@ import Prelude ((+), (-))
 import Data.Bool (Bool(..), (&&))
 import Data.Function (($))
 import Data.Maybe (Maybe(..), isJust)
+import Data.Monoid (mempty)
 import Data.Semigroup ((<>))
+import qualified Data.List as L
 import qualified Data.Text.Lines as Char
 import qualified Data.Text.Utf8.Lines as Utf8
 import qualified Data.Text.Utf16.Lines as Utf16
 import qualified Data.Text.Mixed.Rope as Mixed
 import Test.Tasty (testGroup, TestTree)
-import Test.Tasty.QuickCheck (testProperty, (===), property, (.&&.), counterexample)
+import Test.Tasty.QuickCheck (Positive(..), conjoin, counterexample, property, testProperty, (===), (.&&.))
 
 import Utils ()
 
@@ -106,4 +108,13 @@ testSuite = testGroup "Utf16 Mixed"
     \i x -> case Mixed.utf16SplitAtPosition i x of
       Just{} -> True
       Nothing -> isJust (Mixed.utf16SplitAtPosition (i <> Utf16.Position 0 1) x)
+
+  , testProperty "forall i in bounds: getLine i x == lines x !! i" $
+    \x -> let lns = Mixed.lines x in
+      conjoin $ L.zipWith (\idx ln -> Mixed.getLine idx x === ln) [0..] lns
+  , testProperty "forall i out of bounds: getLine i x == mempty" $
+    \x (Positive offset) ->
+      let maxIdx = L.genericLength (Mixed.lines x) - 1
+          outOfBoundsIdx = maxIdx + offset
+      in Mixed.getLine outOfBoundsIdx x === mempty
   ]

test/Utf16Rope.hs

@@ -11,11 +11,13 @@ import Prelude ((+), (-))
 import Data.Bool (Bool(..), (&&))
 import Data.Function (($))
 import Data.Maybe (Maybe(..), isJust)
+import Data.Monoid (mempty)
 import Data.Semigroup ((<>))
-import qualified Data.Text.Utf16.Lines as Lines 
+import qualified Data.List as L
+import qualified Data.Text.Utf16.Lines as Lines
 import qualified Data.Text.Utf16.Rope as Rope
 import Test.Tasty (testGroup, TestTree)
-import Test.Tasty.QuickCheck (testProperty, (===), property, (.&&.), counterexample)
+import Test.Tasty.QuickCheck (Positive(..), conjoin, counterexample, property, testProperty, (===), (.&&.))
 
 import Utils ()
 
@@ -66,4 +68,13 @@ testSuite = testGroup "Utf16 Rope"
     \i x -> case Rope.splitAtPosition i x of
       Just{} -> True
       Nothing -> isJust (Rope.splitAtPosition (i <> Lines.Position 0 1) x)
+
+  , testProperty "forall i in bounds: getLine i x == lines x !! i" $
+    \x -> let lns = Rope.lines x in
+      conjoin $ L.zipWith (\idx ln -> Rope.getLine idx x === ln) [0..] lns
+  , testProperty "forall i out of bounds: getLine i x == mempty" $
+    \x (Positive offset) ->
+      let maxIdx = L.genericLength (Rope.lines x) - 1
+          outOfBoundsIdx = maxIdx + offset
+      in Rope.getLine outOfBoundsIdx x === mempty
   ]

test/Utf8Rope.hs

@@ -2,15 +2,17 @@ module Utf8Rope
   ( testSuite
   ) where
 
-import Prelude ()
+import Prelude ((+), (-))
 import Data.Bool (Bool(..))
 import Data.Function (($))
 import Data.Maybe (Maybe(..))
+import Data.Monoid (mempty)
 import Data.Semigroup ((<>))
+import qualified Data.List as L
 import qualified Data.Text.Utf8.Lines as Lines
 import qualified Data.Text.Utf8.Rope as Rope
 import Test.Tasty (testGroup, TestTree)
-import Test.Tasty.QuickCheck (testProperty, (===), property, (.&&.), counterexample)
+import Test.Tasty.QuickCheck (Positive(..), conjoin, counterexample, property, testProperty, (===), (.&&.))
 
 import Utils ()
 
@@ -53,4 +55,13 @@ testSuite = testGroup "Utf8 Rope"
       (Nothing, Just{}) -> counterexample "can split TextLines, but not Rope" False
       (Just{}, Nothing) -> counterexample "can split Rope, but not TextLines" False
       (Just (y, z), Just (y', z')) -> Lines.fromText (Rope.toText y) === y' .&&. Lines.fromText (Rope.toText z) === z'
+
+  , testProperty "forall i in bounds: getLine i x == lines x !! i" $
+    \x -> let lns = Rope.lines x in
+      conjoin $ L.zipWith (\idx ln -> Rope.getLine idx x === ln) [0..] lns
+  , testProperty "forall i out of bounds: getLine i x == mempty" $
+    \x (Positive offset) ->
+      let maxIdx = L.genericLength (Rope.lines x) - 1
+          outOfBoundsIdx = maxIdx + offset
+      in Rope.getLine outOfBoundsIdx x === mempty
   ]