From 1a45ec233037096ae93d431395777ae6fde0a457 Mon Sep 17 00:00:00 2001
From: Arity-T <tish.mainmail@gmail.com>
Date: Sun, 8 Dec 2024 19:45:21 +0300
Subject: [PATCH] =?UTF-8?q?=D0=A4=D0=B8=D0=BD=D0=B0=D0=BB=D1=8C=D0=BD?=
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---
 coursework/part1/src/Lib.hs | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/coursework/part1/src/Lib.hs b/coursework/part1/src/Lib.hs
index 943d290..6b8389f 100644
--- a/coursework/part1/src/Lib.hs
+++ b/coursework/part1/src/Lib.hs
@@ -61,10 +61,10 @@ data Operation = Add | Sub | Mul | Div deriving Show
 
 operationToString :: Operation -> String
 operationToString op = case op of
-    Add -> " + "
-    Sub -> " - "
-    Mul -> " * "
-    Div -> " / " 
+    Add -> "+"
+    Sub -> "-"
+    Mul -> "*"
+    Div -> "/" 
 
 operationToOperator :: Operation -> (Int -> Int -> Int)
 operationToOperator op = case op of
@@ -84,3 +84,19 @@ operation = skipSpaces *> (
 
 expression :: Parser Char (Int, Operation, Int)
 expression = (,,) <$> number <*> operation <*> number <* skipSpaces
+
+calculateExpression :: (Int, Operation, Int) -> Int
+calculateExpression (a, op, b) = (operationToOperator op) a b
+
+processExpression :: String -> String
+processExpression s = case runParser expression s of
+    Nothing -> err
+    Just (cs, (a, op, b)) -> case cs of
+        [] -> 
+            show a ++ " " ++ 
+            operationToString op ++ " " ++ 
+            show b ++ " = " ++ 
+            show (calculateExpression (a, op, b))
+        _ -> err
+    where
+        err = error $ "Unable to parse the following expression: \"" ++ s ++ "\""  
\ No newline at end of file