C++ binding (#129)

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/cpp/main.cpp

@@ -0,0 +1,118 @@
+#include <iostream>
+#include "regorus.hpp"
+
+void example()
+{
+    // Create engine
+    regorus::Engine engine;
+
+    // Add policies.
+    engine.add_policy("objects.rego",R"(package objects
+
+rect := {`width`: 2, "height": 4}
+cube := {"width": 3, `height`: 4, "depth": 5}
+a := 42
+b := false
+c := null
+d := {"a": a, "x": [b, c]}
+index := 1
+shapes := [rect, cube]
+names := ["prod", `smoke1`, "dev"]
+sites := [{"name": "prod"}, {"name": names[index]}, {"name": "dev"}]
+e := {
+    a: "foo",
+    "three": c,
+    names[2]: b,
+    "four": d,
+}
+f := e["dev"])");
+
+    // Add data.
+    engine.add_data_json(R"({
+    "one": {
+        "bar": "Foo",
+        "baz": 5,
+        "be": true,
+        "bop": 23.4
+    },
+    "two": {
+        "bar": "Bar",
+        "baz": 12.3,
+        "be": false,
+        "bop": 42
+    }
+})");
+
+    engine.add_data_json(R"({
+    "three": {
+        "bar": "Baz",
+        "baz": 15,
+        "be": true,
+        "bop": 4.23
+    }
+})");
+
+    // Set input.
+    engine.set_input_json(R"({
+    "a": 10,
+    "b": "20",
+    "c": 30.0,
+    "d": true
+})");
+
+    // Eval query.
+    auto result = engine.eval_query("[data.one, input.b, data.objects.sites[1]] = x");
+    if (result) {
+	std::cout<<result.output()<<std::endl;
+    } else {
+	std::cerr<<result.error()<<std::endl;
+    }
+}
+
+int main() {
+
+    // Create engine.
+    regorus::Engine engine;
+
+
+    // Load policies.
+    const char* policies[] = {
+	"../../../tests/aci/framework.rego",
+	"../../../tests/aci/policy.rego",
+	"../../../tests/aci/api.rego",
+    };
+
+    // Add policies and data.
+    for (auto policy : policies) {
+	auto result = engine.add_policy_from_file(policy);
+	if (!result) {
+	    std::cerr<<result.error()<<std::endl;
+	    return -1;
+	}
+    }
+    {
+	auto result = engine.add_data_from_json_file("../../../tests/aci/data.json");
+	if (!result) {
+	    std::cerr<<result.error()<<std::endl;
+	    return -1;
+	}
+    }
+
+    // Set input and eval query.
+    {
+	auto result = engine.set_input_from_json_file("../../../tests/aci/input.json");
+	if (!result) {
+	    std::cerr<<result.error()<<std::endl;
+	    return -1;
+	}
+    }
+    auto result = engine.eval_query("data.framework.mount_overlay = x");
+    if (!result) {
+	std::cerr<<result.error()<<std::endl;
+	return -1;
+    }
+
+    std::cout<<result.output()<<std::endl;
+    
+    example();
+}