jq: add module

(cherry picked from commit dc72aa2305)

modules/misc/news.nix

@@ -888,6 +888,13 @@ in
           to your configuration.
         '';
       }
+
+      {
+        time = "2018-12-12T21:02:05+00:00";
+        message = ''
+          A new module is available: 'programs.jq'.
+        '';
+      }
     ];
   };
 }

modules/modules.nix

@@ -47,6 +47,7 @@ let
     ./programs/home-manager.nix
     ./programs/htop.nix
     ./programs/info.nix
+    ./programs/jq.nix
     ./programs/lesspipe.nix
     ./programs/man.nix
     ./programs/mbsync.nix

modules/programs/jq.nix

@@ -0,0 +1,76 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.programs.jq;
+
+  colorType = mkOption {
+    type = types.str;
+    description = "ANSI color definition";
+    example = "1;31";
+    visible = false;
+  };
+
+  colorsType = types.submodule {
+    options = {
+      null    = colorType;
+      false   = colorType;
+      true    = colorType;
+      numbers = colorType;
+      strings = colorType;
+      arrays  = colorType;
+      objects = colorType;
+    };
+  };
+
+in
+
+{
+  options = {
+    programs.jq = {
+      enable = mkEnableOption "the jq command-line JSON processor";
+
+      colors = mkOption {
+        description = ''
+          The colors used in colored JSON output.</para>
+
+          <para>See <link xlink:href="https://stedolan.github.io/jq/manual/#Colors"/>.
+        '';
+
+        example = literalExample ''
+          {
+            null    = "1;30";
+            false   = "0;31";
+            true    = "0;32";
+            numbers = "0;36";
+            strings = "0;33";
+            arrays  = "1;35";
+            objects = "1;37";
+          }
+        '';
+
+        default = {
+          null    = "1;30";
+          false   = "0;39";
+          true    = "0;39";
+          numbers = "0;39";
+          strings = "0;32";
+          arrays  = "1;39";
+          objects = "1;39";
+        };
+
+        type = colorsType;
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ pkgs.jq ];
+
+    home.sessionVariables = let c = cfg.colors; in {
+      JQ_COLORS = "${c.null}:${c.false}:${c.true}:${c.numbers}:${c.strings}:${c.arrays}:${c.objects}";
+    };
+  };
+}