Make it compile with MicroHs

.github/workflows/mhs-ci.yml

@@ -0,0 +1,49 @@
+name: mhs-ci
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build-mhs-optparse-applicative:
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: checkout mhs repo
+      uses: actions/checkout@v4
+      with:
+        repository: augustss/MicroHs
+        path: mhs
+    - name: make and install mhs
+      run: |
+        cd mhs
+        make install
+
+    # install dependencies
+    - name: compile and install packages
+      run: |
+        PATH="$HOME/.mcabal/bin:$PATH"
+        mcabal -q install ghc-compat
+        mcabal -q install transformers
+        mcabal -q install colour
+        mcabal -q install ansi-terminal-types
+        mcabal -q install ansi-terminal
+        mcabal -q install --git=https://github.com/augustss/prettyprinter.git --dir=prettyprinter prettyprinter
+        mcabal -q install --git=https://github.com/augustss/prettyprinter.git --dir=prettyprinter-ansi-terminal prettyprinter-ansi-terminal
+
+    # optparse-applicative
+    - name: checkout optparse-applicative repo
+      uses: actions/checkout@v4
+      with:
+        path: optparse-applicative
+    - name: compile and install optparse-applicative package
+      run: |
+        PATH="$HOME/.mcabal/bin:$PATH"
+        cd optparse-applicative
+        mcabal install
+
+    - name: cleanup
+      run: |
+        rm -rf $HOME/.mcabal

optparse-applicative.cabal

@@ -118,7 +118,7 @@ library
   if flag(process)
     build-depends:     process                         >= 1.0   && < 1.7
 
-  if !impl(ghc >= 8)
+  if !impl(ghc >= 8) && !impl(mhs)
     build-depends:     semigroups                      >= 0.10  && < 0.21
                      , fail                            == 4.9.*
 

src/Options/Applicative/BashCompletion.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 -- | You don't need to import this module to enable bash completion.
 --
 -- See
@@ -13,7 +14,9 @@ module Options.Applicative.BashCompletion
 
 import Control.Applicative
 import Prelude
+#if !defined(__MHS__)
 import Data.Foldable ( asum )
+#endif
 import Data.List ( isPrefixOf )
 import Data.Maybe ( fromMaybe, listToMaybe )