Add haskell exercises' dependency control.

README.md

@@ -10,40 +10,68 @@ Please see the [contributing guide](https://github.com/exercism/x-api/blob/maste
 
 ### Development Dependencies
 
-Currently, development of the Haskell track assumes that you are using
-GHC 7.8.3 with Haskell Platform installed. The following packages need
-to be installed if not using Haskell Platform:
+There are currently two distinct ways to set up an environment to colaborate
+with the development of the Haskell track:
+
+- Using a global GHC installation.
+- Using *Stack*.
+
+The first method is more convenient when you just want to write code without
+caring too much about which packages are being used. The second one is better
+to track exercise's dependencies and test them against multiple GHC versions.
+
+#### Using a global GHC installation
+
+If you have a recent Haskell Platform installed, probably most of the packages
+you need are already installed for you. Otherwise, you can manually install
+the missing ones.
+
+The following is the list of all packages used in this repository, just don't
+trust this list to be updated.
+
+These packages come installed with GHC:
+
+- array
+- base
+- containers
+- filepath
+- directory
+- process
+- time
+- unix
+
+These are already installed in recent version of the Haskell Platform:
+
+- attoparsec
+- HUnit
+- text
+- parallel
+- QuickCheck
+- random
+- split
+- stm
+- vector
+
+These you will have to add to your instalation:
+
+- lens
+- old-locale
+
+##### Installing missing packages
 
 ```bash
-$ comm -13 \
-  <(ghc-pkg --global list --simple-output --names-only \
-  | tr ' ' '\n') \
-  <(find . -name '*.hs' \
-  | xargs awk \
-    '/^import/ {if ($2 == "qualified") {print $3} else {print $2}}' \
-  | sort -u \
-  | xargs -n1 ghc-pkg find-module --simple-output --names-only \
-  | cut -d' ' -f1 \
-  | sort -u)
-HUnit
-QuickCheck
-attoparsec
-parallel
-random
-regex-base
-regex-compat
-split
-stm
-text
-vector
+$ cabal install lens
 ```
 
-### Running tests
+This will download and installed the package named *lens*.
+
+
+##### Running tests
 
 All the tests:
 
 ```bash
-$./_test/check-exercises.hs
+$ ./_test/check-exercises.hs
 -- accumulate
 Cases: 5  Tried: 5  Errors: 0  Failures: 0
 […]
@@ -68,6 +96,91 @@ Cases: 8  Tried: 8  Errors: 0  Failures: 0
 SUCCESS!
 ```
 
+#### Using Stack
+
+If you have stack installed, you can use it to handle all the dependencies
+for you. But first, you need to transform the exercises in *stack projects*.
+
+##### Creating a project for an exercise
+
+The `_test/stackalize` bash script will extract the exercise's dependencies
+from `_test/dependencies.txt` and create a *stack project* for you:
+
+```bash
+$ _test/stackalize --resolver lts-6.4 exercises/leap
+```
+
+This will transform the exercise *leap* in a *stack project* using the
+resolver *lts-6.4*. Change it for your favourite [Stackage snapshot](https://www.stackage.org/snapshots).
+
+*You can make you life easier adding _test to your path.*
+
+##### Testing with default settings
+
+To download, install the compiler and packages needed, compile and test an
+exercise, run the following commands:
+
+```bash
+$ cd exercises/leap
+$ stack test
+```
+
+##### Testing with advanced options
+
+Testing if it compiles without warnings and pass the tests:
+
+```bash
+$ stack clean
+$ stack test --pedantic
+```
+
+Testing with a specific resolver:
+
+```bash
+$ stack test --resolver lts-2.22           # GHC-7.8.4
+$ stack test --resolver lts-6.4            # GHC-7.10.3
+$ stack test --resolver nightly-2016-06-21 # GHC-8.0.1
+$ stack test --resolver nightly            # Newest compiler and packages.
+```
+
+If you are making major changes to an exercise, it's recommended that
+you test it against those three versions of GHC with `--pedantic`, to be sure
+it will not fail when your *pull request* is tested on *Travis-CI*.
+
+##### Undoing the stack project
+
+If you need to make a *commit*, you can remove the *stack project* and
+change the exercise back to it's previous form:
+
+```bash
+$ stackalize --undo exercises/leap
+```
+
+This command will intentionally leave the *.stack-work* folder intact,
+to preserve the cache in case you decide to test it with *stack* again.
+
+#### The Exercises
+
+Each exercise in the Haskell track is composed of at least two files:
+
+- *name_test.hs*    # Both filenames must be all lowecase and any deviations
+- *example.hs*      # will generate failures in the future.
+
+Optionally, a third file with a stub can also be provided:
+
+- *ModuleName.hs*   # This file must be named exactly as the module.
+
+#### Tracking dependencies
+
+We also keep track of all the packages used by the examples and test files in
+*_test/dependencies.txt*. If you are implementing a new exercise or changing
+the dependencies of a existing one, please don't forget to update it.
+
+At the moment, we may not detect incorrectly specified dependencies in your
+*pull requests* automatically. But soon we expect *Travis-CI* be able to
+catch it, so please declare in *dependencies.txt* all the packages used by
+the examples and tests.
+
 ## License
 
 The MIT License (MIT)

_test/dependencies

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+
+programName=`basename "$0"`
+dependencies="`dirname ${BASH_SOURCE}`/dependencies.txt"
+example="example.hs"
+testSuffix="_test.hs"
+
+getDependencies () {
+  (
+    for pattern in "$@"; do
+      grep "${pattern}" "${dependencies}" | cut -d: -f2 | xargs -n1
+    done
+  ) | sort -u
+}
+
+exampleDependencies () {
+  (
+    for exercise in "$@"; do
+      getDependencies "${exercise}/${example}"
+    done
+  ) | sort -u
+}
+
+testDependencies () {
+  (
+    for exercise in "$@"; do
+      getDependencies "${exercise}/${exercise}${testSuffix}"
+    done
+  ) | sort -u
+}
+
+selectedDependencies () {
+  comm ${commArgs} --output-delimiter " " \
+       <(exampleDependencies "$@")        \
+       <(testDependencies "$@") | xargs -n1
+}
+
+eval set -- `getopt -o "" --long file:,examples,tests,only-in-examples,only-in-tests,examples-and-tests,examples-xor-tests -n ${programName} -- "$@"`
+
+commArgs=""
+
+while true ; do
+    case "$1" in
+        --examples          ) commArgs="-2"           ; shift            ;;
+        --tests             ) commArgs="-1"           ; shift            ;;
+        --only-in-examples  ) commArgs="-23"          ; shift            ;;
+        --only-in-tests     ) commArgs="-13"          ; shift            ;;
+        --examples-and-tests) commArgs="-12"          ; shift            ;;
+        --examples-xor-tests) commArgs="-3"           ; shift            ;;
+        --file              ) case "$2" in
+                                  "")                   shift 2          ;;
+                                  * ) dependencies=$2 ; shift 2          ;;
+                              esac ;;
+        --                  )                           shift   ; break  ;;
+        *) echo "$0: Unexpected error using getopt."            ; exit 1 ;;
+    esac
+done
+
+selectedDependencies "$@"

_test/dependencies.txt

@@ -0,0 +1,140 @@
+accumulate/example.hs: base
+accumulate/accumulate_test.hs: base HUnit
+allergies/example.hs: base
+allergies/allergies_test.hs: base HUnit
+anagram/example.hs: base
+anagram/anagram_test.hs: base HUnit
+atbash-cipher/example.hs: base split
+atbash-cipher/atbash-cipher_test.hs: base HUnit
+bank-account/example.hs: base stm
+bank-account/bank-account_test.hs: base HUnit
+beer-song/example.hs: base
+beer-song/beer-song_test.hs: base HUnit
+binary/example.hs: base
+binary/binary_test.hs: base HUnit
+binary-search-tree/example.hs: base
+binary-search-tree/binary-search-tree_test.hs: base HUnit
+bob/example.hs: base
+bob/bob_test.hs: base HUnit
+clock/example.hs: base
+clock/clock_test.hs: base HUnit
+connect/example.hs: base array
+connect/connect_test.hs: base HUnit
+crypto-square/example.hs: base split
+crypto-square/crypto-square_test.hs: base HUnit
+custom-set/example.hs: base
+custom-set/custom-set_test.hs: base HUnit
+difference-of-squares/example.hs: base
+difference-of-squares/difference-of-squares_test.hs: base HUnit
+etl/example.hs: base containers
+etl/etl_test.hs: base HUnit containers
+food-chain/example.hs: base array
+food-chain/food-chain_test.hs: base HUnit
+forth/example.hs: base containers text
+forth/forth_test.hs: base HUnit text
+gigasecond/example.hs: base time
+gigasecond/gigasecond_test.hs: base HUnit old-locale time
+go-counting/example.hs: base array containers
+go-counting/go-counting_test.hs: base HUnit containers
+grade-school/example.hs: base containers
+grade-school/grade-school_test.hs: base HUnit
+grains/example.hs: base
+grains/grains_test.hs: base HUnit
+hamming/example.hs: base
+hamming/hamming_test.hs: base HUnit
+hexadecimal/example.hs: base
+hexadecimal/hexadecimal_test.hs: base HUnit
+house/example.hs: base
+house/house_test.hs: base HUnit
+kindergarten-garden/example.hs: base containers split
+kindergarten-garden/kindergarten-garden_test.hs: base HUnit
+largest-series-product/example.hs: base
+largest-series-product/largest-series-product_test.hs: base HUnit
+leap/example.hs: base
+leap/leap_test.hs: base HUnit
+lens-person/example.hs: base lens time
+lens-person/lens-person_test.hs: base HUnit time
+linked-list/example.hs: base stm
+linked-list/linked-list_test.hs: base HUnit
+list-ops/example.hs: base
+list-ops/list-ops_test.hs: base HUnit
+luhn/example.hs: base
+luhn/luhn_test.hs: base HUnit
+matrix/example.hs: base vector
+matrix/matrix_test.hs: base HUnit vector
+meetup/example.hs: base time
+meetup/meetup_test.hs: base HUnit time
+minesweeper/example.hs: base array
+minesweeper/minesweeper_test.hs: base HUnit
+nth-prime/example.hs: base
+nth-prime/nth-prime_test.hs: base HUnit
+nucleotide-count/example.hs: base containers
+nucleotide-count/nucleotide-count_test.hs: base HUnit containers
+ocr-numbers/example.hs: base containers split
+ocr-numbers/ocr-numbers_test.hs: base HUnit
+octal/example.hs: base
+octal/octal_test.hs: base QuickCheck
+palindrome-products/example.hs: base
+palindrome-products/palindrome-products_test.hs: base HUnit containers
+parallel-letter-frequency/example.hs: base containers parallel text
+parallel-letter-frequency/parallel-letter-frequency_test.hs: base HUnit containers text
+pascals-triangle/example.hs: base
+pascals-triangle/pascals-triangle_test.hs: base HUnit
+phone-number/example.hs: base
+phone-number/phone-number_test.hs: base HUnit
+pig-latin/example.hs: base
+pig-latin/pig-latin_test.hs: base HUnit
+pov/example.hs: base
+pov/pov_test.hs: base HUnit
+prime-factors/example.hs: base
+prime-factors/prime-factors_test.hs: base HUnit
+pythagorean-triplet/example.hs: base
+pythagorean-triplet/pythagorean-triplet_test.hs: base HUnit
+queen-attack/example.hs: base
+queen-attack/queen-attack_test.hs: base HUnit
+raindrops/example.hs: base
+raindrops/raindrops_test.hs: base HUnit
+rna-transcription/example.hs: base
+rna-transcription/rna-transcription_test.hs: base HUnit
+robot-name/example.hs: base random
+robot-name/robot-name_test.hs: base HUnit
+robot-simulator/example.hs: base
+robot-simulator/robot-simulator_test.hs: base HUnit
+roman-numerals/example.hs: base
+roman-numerals/roman-numerals_test.hs: base HUnit
+saddle-points/example.hs: base array containers
+saddle-points/saddle-points_test.hs: base HUnit array
+say/example.hs: base array
+say/say_test.hs: base HUnit
+scrabble-score/example.hs: base containers
+scrabble-score/scrabble-score_test.hs: base HUnit
+secret-handshake/example.hs: base
+secret-handshake/secret-handshake_test.hs: base HUnit
+series/example.hs: base
+series/series_test.hs: base HUnit
+sgf-parsing/example.hs: base attoparsec containers text
+sgf-parsing/sgf-parsing_test.hs: base HUnit containers text
+sieve/example.hs: base vector
+sieve/sieve_test.hs: base HUnit
+simple-cipher/example.hs: base random
+simple-cipher/simple-cipher_test.hs: base HUnit
+simple-linked-list/example.hs: base
+simple-linked-list/simple-linked-list_test.hs: base HUnit
+space-age/example.hs: base
+space-age/space-age_test.hs: base HUnit
+strain/example.hs: base
+strain/strain_test.hs: base HUnit
+sublist/example.hs: base
+sublist/sublist_test.hs: base HUnit
+sum-of-multiples/example.hs: base
+sum-of-multiples/sum-of-multiples_test.hs: base HUnit
+triangle/example.hs: base containers
+triangle/triangle_test.hs: base HUnit
+trinary/example.hs: base
+trinary/trinary_test.hs: base QuickCheck
+word-count/example.hs: base containers split
+word-count/word-count_test.hs: base HUnit containers
+wordy/example.hs: base attoparsec text
+wordy/wordy_test.hs: base HUnit
+zipper/example.hs: base
+zipper/zipper_test.hs: base HUnit