From f46dafc461e4ee3fa1637051284f89b443f00a51 Mon Sep 17 00:00:00 2001
From: Edoardo La Greca
Date: Tue, 9 Sep 2025 20:38:00 +0200
Subject: add files for lecture 7's homework

---
 lec07/Buffer.hs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 lec07/Buffer.hs

(limited to 'lec07/Buffer.hs')

diff --git a/lec07/Buffer.hs b/lec07/Buffer.hs
new file mode 100644
index 0000000..6eb55af
--- /dev/null
+++ b/lec07/Buffer.hs
@@ -0,0 +1,28 @@
+module Buffer where
+
+-- Type class for data structures that can represent the text buffer
+-- of an editor.
+
+class Buffer b where
+
+  -- | Convert a buffer to a String.
+  toString :: b -> String
+
+  -- | Create a buffer from a String.
+  fromString :: String -> b
+
+  -- | Extract the nth line (0-indexed) from a buffer.  Return Nothing
+  -- for out-of-bounds indices.
+  line :: Int -> b -> Maybe String
+
+  -- | @replaceLine n ln buf@ returns a modified version of @buf@,
+  --   with the @n@th line replaced by @ln@.  If the index is
+  --   out-of-bounds, the buffer should be returned unmodified.
+  replaceLine :: Int -> String -> b -> b
+
+  -- | Compute the number of lines in the buffer.
+  numLines :: b -> Int
+
+  -- | Compute the value of the buffer, i.e. the amount someone would
+  --   be paid for publishing the contents of the buffer.
+  value :: b -> Int
-- 
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