mistral: add initial formula

Formula/mistral.rb

@@ -0,0 +1,55 @@
+class Mistral < Formula
+  desc "Open source constraint programming library and FlatZinc solver written in C++"
+  homepage "https://github.com/ehebrard/Mistral-2.0"
+  url "https://github.com/ehebrard/Mistral-2.0/archive/83de8f7b8cc7f1fc41baa9befc89c91674775ea4.tar.gz"
+  version "2020-08-25"
+  sha256 "e52a4e5694a8cb17233b575c175c8d428b6589f77b8d191adacc8ecab947f782"
+  license "AGPL-3.0-only"
+  head "https://github.com/ehebrard/Mistral-2.0.git", branch: "master"
+
+  depends_on "boost" => :build
+  depends_on "python"
+
+  def install
+    system "make", "-C", "fz"
+
+    bin.install "fz/mistral-fzn"
+    inreplace "fz/mistral-fz" do |s|
+      s.gsub!("env python", "env python3")
+      s.gsub!("mcmd = ['mistral-fzn']", "mcmd = ['#{bin}/mistral-fzn']")
+    end
+    bin.install "fz/mistral-fz"
+
+    (share / "minizinc").mkpath
+    (share / "minizinc").install "fz/mznlib" => "mistral"
+
+    (share / "minizinc/solvers").mkpath
+    (share / "minizinc/solvers/mistral.msc").write <<~EOS
+      {
+        "id": "org.mistral.mistral",
+        "name": "Mistral",
+        "description": "Mistral FlatZinc interface",
+        "version": "#{version}",
+        "mznlib": "#{share}/minizinc/mistral",
+        "executable": "#{bin}/mistral-fz",
+        "tags": ["cp", "int"],
+        "stdFlags": ["-a"],
+        "extraFlags": [],
+        "supportsMzn": false,
+        "supportsFzn": true,
+        "needsSolns2Out": true,
+        "needsMznExecutable": false,
+        "needsStdlibDir": false,
+        "isGUIApplication": false
+      }
+    EOS
+  end
+
+  test do
+    (testpath/"test.fzn").write <<~EOS
+      var bool: x1;
+      solve satisfy;
+    EOS
+    assert_match "----------", shell_output("#{bin}/mistral-fz test.fzn").strip
+  end
+end