diff --git a/.github/workflows/haskell.yml b/.github/workflows/haskell.yml
new file mode 100644
index 0000000..347afd2
--- /dev/null
+++ b/.github/workflows/haskell.yml
@@ -0,0 +1,43 @@
+name: Haskell CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-haskell@v1
+      with:
+        ghc-version: '8.10.3'
+        cabal-version: '3.2'
+
+    - name: Cache
+      uses: actions/cache@v3
+      env:
+        cache-name: cache-cabal
+      with:
+        path: ~/.cabal
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/*.cabal') }}-${{ hashFiles('**/cabal.project') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+
+    - name: Install dependencies
+      run: |
+        cabal update
+        cabal build --only-dependencies --enable-tests --enable-benchmarks
+    - name: Build
+      run: cabal build --enable-tests --enable-benchmarks all
+    - name: Run tests
+      run: cabal test all
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c44b63d..0b3be96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,3 +8,7 @@
 
 * First version revised A. Added two new functions.
 
+## 0.1.2.0 -- 2024-09-28
+
+* First version revised B. Some code changes that reduce a generated stg code.
+
diff --git a/Data/IntermediateStructures1.hs b/Data/IntermediateStructures1.hs
index 368a096..5d50cd8 100644
--- a/Data/IntermediateStructures1.hs
+++ b/Data/IntermediateStructures1.hs
@@ -10,7 +10,7 @@
 
 {-# LANGUAGE NoImplicitPrelude, BangPatterns #-}
 {-# OPTIONS_HADDOCK -show-extensions #-}
-
+{-# OPTIONS_GHC -O #-}
 
 module Data.IntermediateStructures1
  (
@@ -30,13 +30,21 @@ import GHC.List (concatMap)
 
 -- | Function that applies additional function @f :: a -> [a]@ to @a@ if @p :: a -> Bool@ and @p a = True@
 mapI :: (a -> Bool) -> (a -> [a]) -> [a] -> [a]
-mapI p f = concatMap (\x -> if p x then f x else [x])
-{-# INLINE mapI #-}
+mapI p f (x:xs)  = 
+     case p x of
+       True -> f x `mappend` mapI p f xs
+       _    -> x:mapI p f xs
+mapI _ _ _ = []
+{-# NOINLINE mapI #-}
 
 -- | Function that applies additional function @f :: a -> [[a]]@ to @a@ if @p :: a -> Bool@ and @p a = True@
 map2I :: (a -> Bool) -> (a -> [[a]]) -> [a] -> [a]
-map2I p f = mconcat . concatMap (\x -> if p x then f x else [[x]])
-{-# INLINE map2I #-}
+map2I p f (x:xs) = 
+   case p x of
+       True -> (mconcat . f $ x) `mappend` map2I p f xs
+       _    -> x : map2I p f xs
+map2I _ _ _ = []
+{-# NOINLINE map2I #-}
 
 -- | Some general transformation where the arguments that are not present are calculated from the one data argument @a@ being just present. Can be used to contstruct function @a -> d@ from some additional ideas.
 inter :: (a -> b) -> (a -> c) -> (a -> b -> c -> d) -> a -> d
diff --git a/README.md b/README.md
index ce0f386..fa8976b 100644
--- a/README.md
+++ b/README.md
@@ -1,24 +1,4 @@
- Devotion
- ========
-
-The author would like to devote this project to support the [Foundation Gastrostars](https://gastrostars.nl).
-
-The foundation founder is [Emma Kok](https://www.emmakok.nl).
-
-On the 05/01/2024 Emma starts a world tour with [André Rieu and Johann Strauss Orchestra](https://www.andrerieu.com).
-
-On the 06/01/2024 there are a feast of Epiphany, and Sophie's Kok, a sister of Emma, 19th Birthday (she is 18). Therefore, the version 0.1.1.0 is devoted also to her.
-
-Besides, you can support Ukraine and Ukrainian people. 
+You can support Ukraine and Ukrainian people. 
 
 All support is welcome, including donations for the needs of the Ukrainian army, IDPs and refugees.
 
-If you would like to share some financial support with Gastrostars, please, contact the mentioned foundation
-using the URL:
-
-[Contact Foundation GASTROSTARS](https://gastrostars.nl/hou-mij-op-de-hoogte)
-
-or 
-
-[Donation Page](https://gastrostars.nl/doneren)
-
diff --git a/intermediate-structures.cabal b/intermediate-structures.cabal
index 54f7ae8..efb0dcb 100644
--- a/intermediate-structures.cabal
+++ b/intermediate-structures.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               intermediate-structures
-version:            0.1.1.0
+version:            0.1.2.0
 synopsis:
     Some simple functions to deal with transformations from structures to other ones, basically lists.
 
@@ -19,7 +19,6 @@ build-type:         Simple
 extra-doc-files:    CHANGELOG.md, README.md
 
 common warnings
-    ghc-options: -Wall
 
 library
     import:           warnings