Add support for cargo doc

build.nix

@@ -3,7 +3,10 @@ src:
   cargoBuild
 , #| What command to run during the test phase
   cargoTest ? "cargo test --$CARGO_BUILD_PROFILE"
+, #| What command to run during the optional doc phase
+  cargoDoc ? "cargo doc --offline"
 , doCheck ? true
+, doDoc ? true
 , name
 , version
 , rustc
@@ -49,6 +52,9 @@ with rec
           name
           version;
 
+        outputs = [ "out" ] ++ lib.optional doDoc "doc";
+        preInstallPhases = lib.optional doDoc [ "docPhase" ];
+
         CARGO_BUILD_PROFILE = if release then "release" else "debug";
 
         # Otherwise specifying CMake as a dep breaks the build
@@ -149,6 +155,17 @@ with rec
             runHook postCheck
           '';
 
+
+        docPhase = lib.optionalString doDoc ''
+          runHook preDoc
+
+          echo "Running doc command:"
+          echo "  ${cargoDoc}"
+          ${cargoDoc}
+
+          runHook postDoc
+        '';
+
         installPhase =
           ''
             runHook preInstall
@@ -183,6 +200,10 @@ with rec
             mkdir -p $out
             cp -r target $out
 
+            ${lib.optionalString doDoc ''
+            mv $out/target/doc $doc
+            ''}
+
             runHook postInstall
           '';
       };

default.nix

@@ -162,6 +162,7 @@ with rec
                 (attrs //
                 { cargoBuild = "source ${buildDepsScript}";
                   doCheck = false;
+                  doDoc = false;
                   cargolockPath = builtinz.writeTOML cargolock;
                   cargotomlPath = builtinz.writeTOML
                     (