Add support for package extensions

script/test

@@ -80,6 +80,11 @@ pushd tests/library-2
 ./test
 popd
 
+banner "Test extensions"
+pushd tests/extensions
+./test
+popd
+
 banner "Test stack-exe formatting"
 list=$(shfmt -i 2 -l bin/snack)
 if [[ -n "$list" ]]; then

snack-lib/default.nix

@@ -25,7 +25,8 @@ let
   buildModule = ghcWith: modSpec:
     let
       ghc = ghcWith modSpec.moduleDependencies;
-      ghcOpts = modSpec.moduleGhcOpts;
+      exts = modSpec.moduleExtensions;
+      ghcOpts = modSpec.moduleGhcOpts ++ (map (x: "-X${x}") exts);
       ghcOptsArgs = lib.strings.escapeShellArgs ghcOpts;
       objectName = modSpec.moduleName;
       builtDeps = map (buildModule ghcWith) modSpec.moduleImports;
@@ -154,7 +155,8 @@ let
 
   ghciWithModules = ghcWith: modSpecs:
     let
-      ghcOpts = allTransitiveGhcOpts modSpecs;
+      ghcOpts = allTransitiveGhcOpts modSpecs
+        ++ (map (x: "-X${x}") (allTransitiveExtensions modSpecs));
       ghc = ghcWith (allTransitiveDeps modSpecs);
       ghciArgs = lib.strings.escapeShellArgs
         (ghcOpts ++ absoluteModuleFiles);
@@ -213,6 +215,11 @@ let
             modName).packageDependencies
             modName
           ;
+        extsByModuleName = modName:
+          (pkgSpecByModuleName
+            pkgSpec
+            (abort "asking extensions for external module: ${modName}")
+            modName).packageExtensions;
         ghcOptsByModuleName = modName:
           (pkgSpecByModuleName
             pkgSpec
@@ -224,6 +231,7 @@ let
             filesByModuleName = pkgSpec.packageExtraFiles;
             dirsByModuleName = pkgSpec.packageExtraDirectories;
             depsByModuleName = depsByModuleName;
+            extsByModuleName = extsByModuleName;
             ghcOptsByModuleName = ghcOptsByModuleName;
           };
 

snack-lib/module-spec.nix

@@ -15,6 +15,7 @@ rec {
     modDirs:
     modBase:
     modDeps:
+    modExts:
     modGhcOpts:
     { moduleName = modName;
 
@@ -29,6 +30,7 @@ rec {
         then modDeps
         else abort "module dependencies should be a list";
       moduleGhcOpts = modGhcOpts;
+      moduleExtensions = modExts;
     };
 
 
@@ -37,6 +39,7 @@ rec {
       , filesByModuleName
       , dirsByModuleName
       , depsByModuleName
+      , extsByModuleName
       , ghcOptsByModuleName
       }:
       result:
@@ -56,6 +59,7 @@ rec {
             (dirsByModuleName modName)
             (baseByModuleName modName)
             (depsByModuleName modName)
+            (extsByModuleName modName)
             (ghcOptsByModuleName modName);
           };
         empty = {} ;
@@ -71,6 +75,7 @@ rec {
 
   allTransitiveDeps = allTransitiveLists "moduleDependencies" lib.id;
   allTransitiveGhcOpts = allTransitiveLists "moduleGhcOpts" lib.id;
+  allTransitiveExtensions = allTransitiveLists "moduleExtensions" lib.id;
   allTransitiveDirectories =
     allTransitiveLists
       "moduleDirectories"

snack-lib/package-spec.nix

@@ -13,6 +13,7 @@ rec {
     , main ? null
     , ghcOpts ? []
     , dependencies ? []
+    , extensions ? []
     , extra-files ? []
     , extra-directories ? []
     , packages ? []
@@ -20,6 +21,7 @@ rec {
     { packageMain = main;
       packageBase = src;
       packageGhcOpts = ghcOpts;
+      packageExtensions = extensions;
       packageDependencies = mkPerModuleAttr dependencies;
 
       # TODO: merge extra files and extra dirs together

tests/extensions/Main.hs

@@ -0,0 +1,5 @@
+module Main where
+
+import Data.Text
+
+main = putStrLn $ unpack "hello"

tests/extensions/golden

@@ -0,0 +1 @@
+hello

tests/extensions/snack.nix

@@ -0,0 +1,5 @@
+{ main = "Main";
+  src = ./.;
+  dependencies = [ "text" ];
+  extensions = [ "OverloadedStrings" ];
+}

tests/extensions/test

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# vim: ft=sh sw=2 et
+
+set -euo pipefail
+
+$SNACK build
+$SNACK run | diff golden -
+
+TMP_FILE=$(mktemp)
+
+capture_io "$TMP_FILE" main | $SNACK ghci
+
+diff golden $TMP_FILE
+rm $TMP_FILE