flakes for hffix library and fixprint app

fixprint default to color output.

.gitignore

@@ -21,3 +21,4 @@ util/bin
 tags
 README.html
 test/data/*.fix
+result

README.md

@@ -549,13 +549,33 @@ for various parts of the library.
 
 ### Nix
 
-The file `flake.nix` declares a *Nix* shell development environment which provides all
+We have a `flake.nix`.
+
+```
+nix flake show github:jamesdbrock/hffix
+```
+
+#### Development
+
+The `flake.nix` declares a *Nix* shell development environment which provides all
 dependencies for every target in the `Makefile`, including *Doxygen*.
 Enter the *Nix* shell by
 [installing *Nix*](https://nixos.org/download.html)
 and then running `nix develop` in this directory. From the `nix develop` prompt,
 you will be able to build all `Makefile` targets.
 
+#### Package
+
+The *Nix* `hffix` package will provide the `hffix` C++ library.
+
+#### Apps
+
+Run the `fixprint` utility:
+
+```
+nix run github:jamesdbrock/hffix#fixprint
+```
+
 ### Pull Requests
 
 Pull requests welcome!

flake.nix

@@ -10,18 +10,64 @@
     inputs.flake-utils.lib.eachDefaultSystem (system:
     let
       pkgs = import nixpkgs { inherit system; };
+      version = "1.4.0";
     in
-    {
-        devShells.default = pkgs.mkShell {
-          nativeBuildInputs = with pkgs; [ doxygen stack gmp zlib ];
-          buildInputs = with pkgs; [ boost ];
-          LC_ALL = "C.UTF-8";
-          shellHook = ''
-            echo ""
-            echo '  hffix Development Environment'
-            echo '  To run the test suite: make test'
-            echo ""
+    rec {
+      devShells.default = pkgs.mkShell {
+        nativeBuildInputs = with pkgs; [ doxygen stack gmp zlib ];
+        buildInputs = with pkgs; [ boost ];
+        LC_ALL = "C.UTF-8";
+        shellHook = ''
+          echo ""
+          echo '  hffix Development Environment'
+          echo '  To run the test suite: make test'
+          echo ""
+        '';
+      };
+      packages = rec {
+        hffix = pkgs.stdenv.mkDerivation {
+          pname = "hffix";
+          inherit version;
+          src = ./include;
+          meta = with pkgs.lib; {
+            description = "Header-only C++ library for FIX (Financial Information eXchange) protocol";
+            license = licenses.mit;
+            platforms = platforms.all;
+          };
+          unpackPhase = ''
           '';
+          buildPhase = ''
+          '';
+          installPhase = ''
+            mkdir -p $out/include
+            cp -r $src/* $out/include
+          '';
+        };
+        fixprint = pkgs.stdenv.mkDerivation {
+          pname = "fixprint";
+          inherit version;
+          srcs = [./util/src];
+          nativeBuildInputs = [ hffix ];
+          sourceRoot = ".";
+          meta = with pkgs.lib; {
+            description = "Print FIX messages from stdin to stdout in human-readable format";
+            license = licenses.mit;
+            platforms = platforms.all;
+          };
+          buildPhase = ''
+            $CXX -o fixprint src/fixprint.cpp
+          '';
+          installPhase = ''
+            mkdir -p $out/bin
+            mv fixprint $out/bin/fixprint
+          '';
+        };
+      };
+      apps = {
+        fixprint = {
+          type = "app";
+          program = "${packages.fixprint}/bin/fixprint";
         };
+      };
     });
 }

util/src/fixprint.cpp

@@ -18,15 +18,24 @@ char buffer[1 << 20]; // Must be larger than the largest FIX message size.
 int main(int argc, char** argv)
 {
     if (argc > 1 && ((0 == std::strcmp("-h", argv[1])) || (0 == std::strcmp("--help", argv[1])))) {
-        std::cout << 
+        std::cout <<
             "fixprint [Options]\n\n"
             "Reads raw FIX encoded data from stdin and writes annotated human-readable FIX to stdout.\n\n"
             "Options:\n"
-            "  -c --color     Color output.\n";
+            "  -c --color     Color output.\n"
+            "     --no-color  No color output.\n\n";
         exit(0);
     }
 
-    bool color = argc > 1 && (0 == std::strcmp("-c", argv[1]) || 0 == std::strcmp("--color", argv[1]));
+    bool color = true;
+    if (argc > 1) {
+        if (0 == std::strcmp("-c", argv[1]))
+            color = true;
+        if (0 == std::strcmp("--color", argv[1]))
+            color = true;
+        if (0 == std::strcmp("--no-color", argv[1]))
+            color = false;
+    }
 
     std::map<int, std::string> field_dictionary;
     hffix::dictionary_init_field(field_dictionary);