Merge pull request #374 from rbasso/travis-add-hlint

travis: Add hlint to Travis-CI checks

Author: petertseng

.travis.yml

@@ -28,13 +28,16 @@ install:
  - travis_retry fetch-configlet
  - travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 -o pack.tgz
  - tar xzf pack.tgz --wildcards --strip-components=1 -C ${HOME}/bin '*/stack'
+ - stack --resolver ${RESOLVER} --install-ghc install hlint
 
 script:
  - |
     set -e
-    configlet .
 
-    # Explicit set the resolver only if it's not the current one.
+    configlet .               # Check basic track configuration.
+    hlint ${TRAVIS_BUILD_DIR} # Run `hlint` on the entire repository.
+
+    # Explicit set exercises' resolver only if it's not the current one.
     if [ "${CURRENT}" != "YES" ]; then
         SET_RESOLVER="--resolver ${RESOLVER}"
     fi

README.md

@@ -50,12 +50,16 @@ stack test --pedantic
 
 ### Running HLint
 
-All code in this repository should be as idiomatic as possible, so it is
-highly recommended to run `hlint` on your sources before opening a
-*pull request*.
+All code in this repository should be as idiomatic as possible, so we
+enforce in [Travis-CI] that it returns `No hints` when processed by
+HLint.
 
-Unless there is a good reason to ignore a suggestion, all submitted
-code is expected to return **No hints** when processed by it.
+It is highly recommended to run `hlint` on your sources before opening
+a *pull request*, so you can fix your code before submitting it for review.
+
+If you are certain that a suggestion given by `hlint` would make the
+code worse, you can [suppress it](https://github.com/ndmitchell/hlint#customizing-the-hints)
+with annotations in the source file.
 
 ## License