haskell: add translator hackage

src/indexers/libraries-io/default.nix

@@ -55,6 +55,9 @@ libraries.io also supports other interesting popularity metrics:
 
       # get platform
       platformQuery=$(jq ".\"$platform\"" -c -r ${l.toFile "platform-map.json" (l.toJSON platformMap)})
+      if [ "$platformQuery" == "null" ]; then
+        platformQuery=$platform
+      fi
 
       echo "Starting to query $numPages pages..."
 

src/indexers/libraries-io/process-result.py

@@ -10,14 +10,15 @@ input = json.load(sys.stdin)
 projects = []
 for package in input:
   versions = package['versions']
-  latest_version =\
-    (sorted(versions, key=lambda v: v['published_at'])[-1])['number']
-  projects.append(dict(
-    id=f"{package['name']}-{latest_version}",
-    name=package['name'],
-    version=latest_version,
-    translator=platform,
-  ))
+  versions = sorted(versions, key=lambda v: v['published_at'], reverse=True)
+  if versions:
+    latest_version = versions[0]['number']
+    projects.append(dict(
+        id=f"{package['name']}-{latest_version}",
+        name=package['name'],
+        version=latest_version,
+        translator=platform,
+    ))
 
 with open(out_file) as f:
   existing_projects = json.load(f)

src/specifications/subsystems/haskell/dream.lock.example.json

@@ -3,6 +3,14 @@
     "compiler": {
       "name": "ghc",
       "version": "8.10.7"
+    },
+    "cabal-files": {
+      "aeson": {
+        "1.2.2.0": {
+          "url": "https://hackage.haskell.org/package/aeson-1.2.2.0/revision/2.cabal",
+          "hash": "sha256:57a8f61df46d5ac6aeb33f01a26267aaf853c82ac9d99dda0f8f3c93a9f740de"
+        }
+      }
     }
   }
 }

src/subsystems/haskell/translators/hackage/default.nix

@@ -0,0 +1,126 @@
+{
+  dlib,
+  lib,
+  ...
+}: let
+  l = lib // builtins;
+in {
+  type = "impure";
+
+  # A derivation which outputs a single executable at `$out`.
+  # The executable will be called by dream2nix for translation
+  # The input format is specified in /specifications/translator-call-example.json.
+  # The first arg `$1` will be a json file containing the input parameters
+  # like defined in /src/specifications/translator-call-example.json and the
+  # additional arguments required according to extraArgs
+  #
+  # The program is expected to create a file at the location specified
+  # by the input parameter `outFile`.
+  # The output file must contain the dream lock data encoded as json.
+  # See /src/specifications/dream-lock-example.json
+  translateBin = {
+    # dream2nix utils
+    subsystems,
+    utils,
+    # nixpkgs dependenies
+    bash,
+    coreutils,
+    curl,
+    gnutar,
+    gzip,
+    haskellPackages,
+    jq,
+    moreutils,
+    nix,
+    python3,
+    writeScriptBin,
+    ...
+  }:
+    utils.writePureShellScript
+    [
+      bash
+      coreutils
+      curl
+      gnutar
+      gzip
+      haskellPackages.cabal-install
+      haskellPackages.ghc
+      jq
+      moreutils
+      nix
+      python3
+    ]
+    ''
+      # accroding to the spec, the translator reads the input from a json file
+      jsonInput=$1
+
+      # read the json input
+      outputFile=$(realpath -m $(jq '.outputFile' -c -r $jsonInput))
+      name=$(jq '.project.name' -c -r $jsonInput)
+      version=$(jq '.project.version' -c -r $jsonInput)
+      source=$(jq '.source' -c -r $jsonInput)
+      relPath=$(jq '.project.relPath' -c -r $jsonInput)
+
+      pushd $TMPDIR
+
+      # download and unpack package source
+      mkdir source
+      curl -L https://hackage.haskell.org/package/$name-$version/$name-$version.tar.gz > $TMPDIR/tarball
+      cd source
+      cat $TMPDIR/tarball | tar xz --strip-components 1
+      # trigger creation of `dist-newstyle` directory
+      cabal update
+      cabal freeze
+      cd -
+
+      # generate arguments for cabal-plan translator
+      echo "{
+        \"source\": \"$TMPDIR/source\",
+        \"outputFile\": \"$outputFile\",
+        \"project\": {
+          \"relPath\": \"\",
+          \"subsystemInfo\": {}
+        }
+      }" > $TMPDIR/newJsonInput
+
+      popd
+
+      # execute cabal-plan translator
+      ${subsystems.haskell.translators.cabal-plan.translateBin} $TMPDIR/newJsonInput
+
+      # finalize dream-lock. Add source and export default package
+      # set correct package version under `packages`
+      export version
+      export hash=$(sha256sum $TMPDIR/tarball | cut -d " " -f 1)
+      cat $outputFile \
+        | python3 ${./fixup-dream-lock.py} $TMPDIR/sourceInfo.json \
+        | sponge $outputFile
+
+    '';
+
+  # If the translator requires additional arguments, specify them here.
+  # When users run the CLI, they will be asked to specify these arguments.
+  # There are only two types of arguments:
+  #   - string argument (type = "argument")
+  #   - boolean flag (type = "flag")
+  # String arguments contain a default value and examples. Flags do not.
+  extraArgs = {
+    # Example: boolean option
+    # Flags always default to 'false' if not specified by the user
+    noDev = {
+      description = "Exclude dev dependencies";
+      type = "flag";
+    };
+
+    # Example: string option
+    theAnswer = {
+      default = "42";
+      description = "The Answer to the Ultimate Question of Life";
+      examples = [
+        "0"
+        "1234"
+      ];
+      type = "argument";
+    };
+  };
+}

src/subsystems/haskell/translators/hackage/fixup-dream-lock.py

@@ -0,0 +1,17 @@
+import json
+import os
+import sys
+
+lock = json.load(sys.stdin)
+version = os.environ.get('version')
+hash = os.environ.get('hash')
+
+# set default package version correctly
+name = lock['_generic']['defaultPackage']
+lock['sources'][name][version] = dict(
+  type="http",
+  url=f"https://hackage.haskell.org/package/{name}-{version}/{name}-{version}.tar.gz",
+  hash=f"sha256:{hash}",
+)
+
+print(json.dumps(lock, indent=2))

src/subsystems/nodejs/translators/npm/default.nix

@@ -71,7 +71,7 @@
 
       # set correct package version under `packages`
       cat $outputFile \
-        | python3 ${./fixup-dream-lock.py} $TMPDIR/sourceInfo.json \
+        | python3 ${./fixup-dream-lock.py} \
         | sponge $outputFile
 
     '';

src/subsystems/rust/translators/crates-io/default.nix

@@ -43,9 +43,9 @@
       version=$(jq '.project.version' -c -r $jsonInput)
 
       pushd $TMPDIR
-      mkdir source
 
       # download and unpack package source
+      mkdir source
       curl -L https://crates.io/api/v1/crates/$name/$version/download > $TMPDIR/tarball
       cd source
       cat $TMPDIR/tarball | tar xz --strip-components 1

src/templates/translators/impure.nix

@@ -67,7 +67,7 @@ in {
       source=$(jq '.source' -c -r $jsonInput)
       relPath=$(jq '.project.relPath' -c -r $jsonInput)
 
-      cd $TMPDIR
+      pushd $TMPDIR
       # TODO:
       # read input files/dirs and produce a json file at $outputFile
       # containing the dream lock similar to /src/specifications/dream-lock-example.json