map version 4 to 4.0

.github/actions/build-foo/action.yml

@@ -1,9 +1,10 @@
 name: Build foo.exe
 description: Build foo.exe
 inputs:
-  version:
-    description: Version to use
+  binary:
+    description: Compiler binary file name
     required: false
+    default: clang++
   platform:
     description: Target platform
     required: true
@@ -23,5 +24,5 @@ runs:
             $flags += '-lpthread'
         }
 
-        & "clang++$version" $flags
+        & '${{ inputs.binary }}' $flags
       shell: pwsh

.github/workflows/test.yml

@@ -50,7 +50,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - name: Set up Clang
+      - id: setup
+        name: Set up Clang
         uses: ./
         with:
           version: '${{ matrix.version }}'
@@ -59,7 +60,7 @@ jobs:
       - name: Build foo.exe
         uses: ./.github/actions/build-foo
         with:
-          version: '${{ matrix.version }}'
+          binary: '${{ steps.setup.outputs.clangxx }}'
       - name: Run foo.exe
         uses: ./.github/actions/run-foo
       - name: Check cc/c++

README.md

@@ -44,6 +44,11 @@ API
 | hardlinks | *any*   | ✓       | Cygwin: don't convert any symlinks.
 |           | 1       |         | Cygwin: convert symlinks in /usr/bin to hardlinks.
 
+| Output  | Example   | Description
+| ------- | --------- | -----------
+| clang   | clang-4.0 | clang compiler binary file name
+| clangxx | clang++-7 | clang++ compiler binary file name
+
 Supported versions
 ------------------
 

action.yml

@@ -92,8 +92,9 @@ runs:
 
             switch -Exact ($Version) {
                 # Since version 7, they dropped the .0 suffix. The earliest
-                # version supported is 5.0 on Bionic; versions 5 and 6 are
-                # mapped to LLVM-friendly 5.0 and 6.0.
+                # version supported is 3.9 on Bionic; versions 4, 5 and 6 are
+                # mapped to LLVM-friendly 4.0, 5.0 and 6.0.
+                '4' { '4.0' }
                 '5' { '5.0' }
                 '6' { '6.0' }
                 default { $Version }