Add simple Racket builder

src/lib/builders.nix

@@ -10,6 +10,7 @@
     nodejs = "granular";
     python = "simple-builder";
     php = "granular";
+    racket = "simple";
   };
 
   # TODO

src/modules/builders/implementation.nix

@@ -11,6 +11,7 @@
     php = "granular-php";
     haskell = "simple-haskell";
     debian = "simple-debian";
+    racket = "simple-racket";
   };
   loader = b: b // {build = callPackageDream b.build {};};
   funcs = config.functions.subsystem-loading;

src/subsystems/racket/builders/simple-racket/default.nix

@@ -0,0 +1,110 @@
+{...}: {
+  type = "pure";
+
+  build = {
+    lib,
+    pkgs,
+    stdenv,
+    # dream2nix inputs
+    externals,
+    ...
+  }: {
+    ### FUNCTIONS
+    # AttrSet -> Bool) -> AttrSet -> [x]
+    getCyclicDependencies, # name: version: -> [ {name=; version=; } ]
+    getDependencies, # name: version: -> [ {name=; version=; } ]
+    getSource, # name: version: -> store-path
+    # to get information about the original source spec
+    getSourceSpec, # name: version: -> {type="git"; url=""; hash="";}
+    ### ATTRIBUTES
+    subsystemAttrs, # attrset
+    defaultPackageName, # string
+    defaultPackageVersion, # string
+    # all exported (top-level) package names and versions
+    # attrset of pname -> version,
+    packages,
+    # all existing package names and versions
+    # attrset of pname -> versions,
+    # where versions is a list of version strings
+    packageVersions,
+    # function which applies overrides to a package
+    # It must be applied by the builder to each individual derivation
+    # Example:
+    #   produceDerivation name (mkDerivation {...})
+    produceDerivation,
+    ...
+  } @ args: let
+    l = lib // builtins;
+
+    # packages to export
+    exportedPackages =
+      {default = exportedPackages.${defaultPackageName};}
+      // (lib.mapAttrs
+        (name: version: {
+          "${version}" = buildRacketWithPackages name;
+        })
+        args.packages);
+
+    allPackageSourceAttrs = l.pipe packageVersions [
+      (l.mapAttrsToList (name: versions: (l.map
+        (ver: let
+          src = getSource name ver;
+          srcDir = src.original or src;
+        in
+          l.nameValuePair name srcDir)
+        versions)))
+      l.flatten
+      l.listToAttrs
+    ];
+
+    # Many of the details mimic https://github.com/Warbo/nix-helpers,
+    # the license of which permits copying as long as we don't try to
+    # patent anything.
+    buildRacketWithPackages = name:
+      produceDerivation "racket-with-${name}-env"
+      (pkgs.runCommandCC "racket-with-${name}-env"
+        {
+          inherit (pkgs) racket;
+          buildInputs = with pkgs; [makeWrapper racket];
+        } ''
+          ${l.toShellVars {"allDepSrcs" = allPackageSourceAttrs;}}
+
+          mkdir -p $TMP/unpack
+
+          for p in ''${!allDepSrcs[@]}
+          do
+            mkdir $TMP/unpack/$p
+            cp -R ''${allDepSrcs[$p]}/. $TMP/unpack/$p
+          done
+
+          export PLTCONFIGDIR=$out/etc
+          mkdir -p $PLTCONFIGDIR
+
+          cp $racket/etc/racket/config.rktd $PLTCONFIGDIR
+
+          $racket/bin/racket -t ${./make-new-config.rkt}
+
+          export TMP_RACO_HOME=$out/tmp-raco-home
+          mkdir -p $TMP_RACO_HOME
+
+          chmod +w -R $TMP/unpack
+          HOME=$TMP_RACO_HOME $racket/bin/raco pkg install --copy $(ls -d $TMP/unpack/*/)
+
+          for SUBPATH in $(ls -d $TMP_RACO_HOME/.local/share/racket/*/); # there is only one SUBPATH (whose name is the version number of Racket)
+          do
+              cp -r -t $PLTCONFIGDIR $SUBPATH/*
+          done
+
+          rm -rf $TMP_RACO_HOME
+
+          mkdir -p $out/bin
+          for EXE in $racket/bin/* $out/etc/bin/*;
+          do
+            NAME=$(basename "$EXE")
+            makeWrapper "$EXE" "$out/bin/$NAME" --set PLTCONFIGDIR "$PLTCONFIGDIR"
+          done
+        '');
+  in {
+    packages = exportedPackages;
+  };
+}

src/subsystems/racket/builders/simple-racket/make-new-config.rkt

@@ -0,0 +1,28 @@
+#lang racket
+
+(require setup/dirs)
+
+(let* ([config-rktd-path (cleanse-path (build-path (find-config-dir) "config.rktd"))]
+       [old-config-ht (with-input-from-file config-rktd-path read)]
+       [property-alist '((bin-search-dirs . "bin/")
+                         (collects-search-dirs . "collects/")
+                         (doc-search-dirs . "doc/")
+                         (include-search-dirs . "include/")
+                         (lib-search-dirs . "lib/")
+                         (links-search-files . "links.rktd")
+                         (man-search-dirs . "man/")
+                         (pkgs-search-dirs . "pkgs/")
+                         (share-search-dirs . "share/"))]
+       [make-path-string (lambda (subpath)
+                           (path->string (cleanse-path (build-path (find-config-dir) subpath))))]
+       [final-config-ht (foldl (match-lambda**
+                                [((cons key subpath) accum)
+                                 (hash-update accum
+                                              key
+                                              (curry cons (make-path-string subpath))
+                                              '(#f))])
+                               old-config-ht
+                               property-alist)])
+  (with-output-to-file config-rktd-path
+    (lambda () (write final-config-ht))
+    #:exists 'replace))