Implement getScreenDimensions

hcat.cabal

@@ -27,9 +27,10 @@ library
       BlockArguments
       OverloadedStrings
       ImportQualifiedPost
-  ghc-options: -Wall -Wunused-packages -fdefer-typed-holes
+  ghc-options: -Wall -fdefer-typed-holes
   build-depends:
       base >=4.13 && <5
+    , process
     , text
   default-language: GHC2021
 
@@ -43,7 +44,7 @@ executable hcat
       BlockArguments
       OverloadedStrings
       ImportQualifiedPost
-  ghc-options: -Wall -Wunused-packages -fdefer-typed-holes
+  ghc-options: -Wall -fdefer-typed-holes
   build-depends:
       base >=4.13 && <5
     , hcat
@@ -61,7 +62,7 @@ test-suite spec
       BlockArguments
       OverloadedStrings
       ImportQualifiedPost
-  ghc-options: -Wall -Wunused-packages -fdefer-typed-holes
+  ghc-options: -Wall -fdefer-typed-holes
   cpp-options: -DTEST
   build-tool-depends:
       hspec-discover:hspec-discover

package.yaml

@@ -13,12 +13,10 @@ dependencies:
   - base >= 4.13 && < 5
 #  - bytestring
 #  - time
-#  - process
 #  - directory
 
 ghc-options:
   - -Wall
-  - -Wunused-packages
   - -fdefer-typed-holes
 
 default-extensions:
@@ -30,6 +28,7 @@ library:
   source-dirs: src
   dependencies:
     - text
+    - process
   verbatim:
     default-language: GHC2021
 

src/HCat/Internal.hs

@@ -4,6 +4,8 @@ module HCat.Internal where
 import Data.Text (Text)
 import Data.Text qualified as T
 
+import System.Process qualified as P
+
 -- | @parseArgs@ takes a list of strings and returns a single FilePath if there was exactly one element.
 --
 -- >>> parseArgs ["foo"]
@@ -67,3 +69,8 @@ paginate (ScreenDimensions rows cols) =
 
 type Pages = [Page]
 type Page = Text
+
+getScreenDimensions :: IO ScreenDimensions
+getScreenDimensions = ScreenDimensions <$> tput "lines" <*> tput "cols"
+ where
+  tput cmd = read <$> P.readProcess "tput" [cmd] ""