More OPA conformant semantics (#62)

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

README.md

@@ -15,32 +15,33 @@ Regorus is available as a library that can be easily integrated into your Rust p
 
 ## Getting Started
 
-[regorus](examples/regorus.rs) is an example program that shows how to integrate Regorus into your project and evaluate Rego policies.
+[examples/regorus](examples/regorus.rs) is an example program that shows how to integrate Regorus into your project and evaluate Rego policies.
 
-To build it, do
+To build and install it, do
 
-    cargo build -r --example regorus
+    cargo install --example regorus --path .
 
 
 Check that the regorus example program is working
 
-    $ target/release/examples/regorus
+    $ regorus
     Usage: regorus <COMMAND>
     
     Commands:
       eval   Evaluate a Rego Query
       lex    Tokenize a Rego policy
-      parse  Parse q Rego policy
+      parse  Parse a Rego policy
       help   Print this message or the help of the given subcommand(s)
-
+    
     Options:
       -h, --help     Print help
-      -V, --version  Print version
+      -V, --version  Print versionUsage: regorus <COMMAND>
+
 
 
 First, let's evaluate a simple Rego expression `1*2+3`
 
-    target/release/examples/regorus eval "1*2+3"
+    regorus eval "1*2+3"
 
 This produces the following output
 
@@ -63,16 +64,11 @@ This produces the following output
 
 Next, evaluate a sample [policy](examples/example.rego) and [input](examples/input.json) (borrowed from [Rego tutorial](https://www.openpolicyagent.org/docs/latest/#2-try-opa-eval)):
 
-    target/release/examples/regorus eval -d examples/example.rego -i examples/input.json data.example
+    regorus eval -d examples/example.rego -i examples/input.json data.example
 
 Finally, evaluate real-world [policies](tests/aci/) used in Azure Container Instances (ACI)
 
-    target/release/examples/regorus eval -d tests/aci/framework.rego \
-        -d tests/aci/policy.rego \
-        -d tests/aci/api.rego  \
-        -d tests/aci/data.json  \
-        -i tests/aci/input.json \
-         data.policy.mount_overlay=x
+    regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.policy.mount_overlay=x
 
 
 ## ACI Policies
@@ -94,26 +90,24 @@ Regorus successfully passes the ACI policy test-suite. It is fast and can run ea
 
 Run the ACI policies in the `tests/aci` directory, using data `tests/aci/data.json` and input `tests/aci/input.json`:
 
-    target/release/examples/regorus eval \
-         -b tests/aci \
-         -d tests/aci/data.json \
-         -i tests/aci/input.json \
-         data.framework.mount_overlay=x
+    regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.policy.mount_overlay=x
+
 
 Verify that [OPA](https://github.com/open-policy-agent/opa/releases) produces the same output
 
-    diff <(target/release/examples/regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x) <(opa eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x)
+    diff <(regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x) \
+         <(opa eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x)
 
 ## Performance
 
 To check how fast Regorus runs on your system, first install a tool like [hyperfine](https://github.com/sharkdp/hyperfine).
 
-   cargo install hyperfine
+    cargo install hyperfine
 
 Then benchmark evaluation of the ACI policies,
 
-    $ hyperfine "target/release/examples/regorus eval -b tests/aci -d tests/aci/data.json -i   tests/aci/input.json data.framework.mount_overlay=x"
-    Benchmark 1: target/release/examples/regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x
+    $ hyperfine "regorus eval -b tests/aci -d tests/aci/data.json -i   tests/aci/input.json data.framework.mount_overlay=x"
+    Benchmark 1: regorus eval -b tests/aci -d tests/aci/data.json -i tests/aci/input.json data.framework.mount_overlay=x
       Time (mean ± σ):       4.6 ms ±   0.2 ms    [User: 4.1 ms, System: 0.4 ms]
       Range (min … max):     4.4 ms …   6.0 ms    422 runs