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-rw-r--r--src/Trammel.hs31
1 files changed, 31 insertions, 0 deletions
diff --git a/src/Trammel.hs b/src/Trammel.hs
index 36c1140..bd3cd32 100644
--- a/src/Trammel.hs
+++ b/src/Trammel.hs
@@ -4,6 +4,7 @@
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE LambdaCase #-}
module Trammel where
import Control.Applicative
@@ -214,3 +215,33 @@ pp t = renderString emptyRenderState t ""
renderSGR :: Pm -> String
renderSGR [] = []
renderSGR xs = ("\ESC["++) . (++"m") . intercalate ";" $ map show xs
+
+
+trammelDrop :: Int -> Trammel String -> Trammel String
+trammelDrop n = \case
+ Append t1 t2 ->
+ case compare n (len t1) of
+ LT -> Append (trammelDrop n t1) t2
+ EQ -> t2
+ GT -> trammelDrop (n - len t1) t2
+ Plain s ->
+ Plain (drop n s)
+ SGR pm t ->
+ SGR pm (trammelDrop n t)
+ Empty ->
+ Empty
+
+
+trammelTake :: Int -> Trammel String -> Trammel String
+trammelTake n = \case
+ Append t1 t2 ->
+ case compare n (len t1) of
+ LT -> trammelTake n t1
+ EQ -> t1
+ GT -> Append t1 (trammelTake (n - len t1) t2)
+ Plain s ->
+ Plain (take n s)
+ SGR pm t ->
+ SGR pm (trammelTake n t)
+ Empty ->
+ Empty